Stereo MPX is the multiplexer. It breaks the two channels apart from the broadcast to be amplified independently. And poly filament fishing line works excellently as dial string. Restoration suppliers charge a bleeding fortune for basically the same thing. That is an absolute BEAST of a unit too.
I would likely avoid fishing line, as that would tend to stretch and slip a lot. FM Stereo is a little complex, once you get into it, with L+R and L-R and all tht fun stuff that was done to try and keep it compaitble with mono receivers at the same time as offering stereo, so the multiplexer (MPX) was quite complex too. Some units had the MPX unit built in, some had an input on the back labelled MPX for an optional MPX unit you could buy as an add on.
Standard monofilament can stretch, but I've never had any issues with the braided poly filament stuff. And it's extremely tough stuff too. Funny enough, I've never actually fished with it. When I make a mistake and have to re-string a set a few times with 'genuine' dial string though, the cost can start to sting. Don't always have a diagram to go by. @@EsotericArctos
It is actually a neat solution as the woofers are way less efficient than the horns, rougly 95dB/m against 105dB/m, therefore a triple push pull set for the woofer nicely will help solving the level. Bi-amping was a good idea in this regard, yet any bi-amping or bi-wiring these days is just introducing extra noisy devices and paralleling over output stages. The setup of this Magnavox set with a nice horn and large woofers is very well sounding by design and modern box speakers are no comparison.
I own a 1961 Concert Grand that I bought from the original owner. He gave me all the documentation and the sales receipt. $1500.00 1961 Dollars, Oh, and he also gave me the demonstration record. Spectacular set
I was born deaf in one ear, I’m a musician, music teacher, and I was enrolled for my masters at American University for their audio technology masters program, you are inspiring! Don’t give up. I also work in IT and have been for 15 years, so your videos are all of the sudden more entertaining and inspiring
This is the holy grail of vintage 60’s hi-fi. Your grand-father knew what he bought, for sure! Very powerful and well designed, he must have been the envy of many! Wow!
I just bought new Kef Q350 bookshelf speakers and new subwoofer. If the music at the end was recorded right off this thing, I’d like to hope my new speakers recreated the analog-to-digital-to-analog sound reasonable accurately. Such a beautiful warm tone!
What's really cool is a lot of the early remote controls were AUDIO. And the remote itself didn't need batteries. There were a series of metal rods, and when you pushed the button, a little hammer would hit the selected rod and make a ringing sound (very high pitched). This was picked up my a microphone on the system being controlled, and the individual tones would activate relays, that would, in turn, operate the system. Quite often for things like volume up and down, actually controlled a motor that turned the volume knob. So if you clicked the remote, the knob on the TV would turn. I've seen one of these still in use by it's owner. And yes, this was a tube TV. And the remote worked just fine, although the range was pretty limited. Which wasn't an issue as the picture tubes were small back then, so you usually sat fairly close anyway.
No expense was spared in the design I Of this. They managed to get three transistors in there, but didn't cheap out with the tubes. Transistors we're probably more expensive at that time though.
I believe the chassis with the sealed bottom is for the FM stereo MPX (multiplex) decoder. That was brand new in 1962 and not all areas had FM stereo broadcasts yet, so it was usually sold as an option. Plus the early tube-based MPX decoders tended to drift, so locating it in a separate chassis away from the heat of the main circuitry helped to improve its performance. For better AM reception, try connecting a long piece of wire to the external antenna terminal. You should be able to pick up skywave signals from hundreds of miles away at night, even if you don't have not much to listen to locally during the daytime.
Anyone who has never heard one of these quality console stereos simply has no clue how incredible they are. The sound is like nothing you can create from even the best equipment today. A few years ago, I was present at a storage warehouse where an abandoned storage bay was being emptied out. They cranked up one of these on the loading dock and it filled the entire warehouse with the richest, most beautiful sound you could ever imagine.
Amazing, active crossovers and dual mono power amps - I've never seen a console type stereo executed this seriously. Also the tweeter horns are unusual and rather impressive.
That is quite a beast! I have had tube type stereo gear (separate components) for more than forty years. The rig I have now has two monoblock amps that use pairs of 6L6 output tubes that can muster around 30 watts or so before they overload; they feed acoustic labyrinth speakers that work quite well, as long as I am not trying to blow the roof off the house. I wonder how much undistorted power those amps are actually capable of under worst-case conditions-- the arrangement with the separate bass channel is a very practical way to allow "fudging" the output transformers in the midrange-treble amplifiers since filtering out the bass frequencies BEFORE the power amps would sidestep the intermodulation distortion that would result with an inadequate output transformer being badly overloaded at low frequencies. At the time, Motorola was noted for their consoles that were skimped and got away with it by doing pre-power-amplifier crossovers.
@donleamon8653 we had an Astro-Sonic when I was a youngster-- it paled in comparison to the Yamaha receiver and Advent speakers that replaced it in the late seventies. . . Those horns are not for me
I like the magnavox coat of arms. Gives it an classy vibe. I can imagine it looking good in an elegant drawing room in a manor. "Jeeves, please be good enough to turn the wireless on to the BBC. Mr Churchill is about to speak."
Good Lord, what a beast! Dual bi-amped monoblock power amplifiers in a home console system in 1962? I never knew there was such a thing! And those horns and 15" woofers look like they would be more at home in a small concert venue! That's a machine to cherish, indeed.
I'm not saying it doesn't sound good but 15" woofers back then didn't have a lot of movement. They were usually quite stiff due to the paper surrounds.
@@bertroost1675 That's certainly true, but then I don't think small concert venues had the SPLs or low-end coverage they have today. I stand by my claim that I haven't seen many, if any, other 15" woofers in loudspeakers intended for home use in the early 1960s.
@@bertroost1675 They were that way because of the usual low amplifier power. They were tuned for efficiency, not low bass extension/spl. Although 'long throw' woofers in sealed cabinets were around already - but only in standalone speakers (mainly Acoustic Research and KLH models). Pro speakers for venues would have mainly used all sorts of horns at the time.
@@danmenes3143 It was quite common for those large 'Texas sized' consoles to have 12" or 15" woofers. In the later years, when they got cheapened, as component stereos became more common and people wouldn't spend as much on a console, this wasn't the case anymore. Sometimes you find 6.5”s with puny amps in huge cabinets.
My friend's parents got a console stereo/TV. When his parents left him home alone one Saturday, he had it cranked so loud, and it sounded so good, that I literally thought it was a live band playing a party until I ran down the street and saw it was just their stereo! Horns and high compliance speakers are incredibly efficient and play really loud.
MPX means "Multiplex" as already mentioned. Early FM tuners and receivers received a monophonic signal. Around 1960 (not sure exactly when) the decision was made to allow some stations to broadcast in stereo. But this had to be done in such a way that a mono receiver would still work OK. There were several competing designs, so until the dust settled, some mfrs brought out the necessary signal to be fed (optionally) to an external "multiplex decoder" which produced stereo outputs. This is the MPX jack on your unit, and implies that it does not have an internal multiplex decoder. Probably units made a year or two after this one had the stereo decoder built-in.
Oops! Looks like this unit not only had MPX out, but also inputs for the externally decoded stereo signals, so that FM Stereo could be selected from the front panel.
The FCC approved the current FM multiplex system in late 1961. Magnavox sold the decoder as an extra cost option until about 1963. Decoders were integrated into the receivers after 1963 when Magnavox went solid state. The decoders show up frequently on EBay.
In my Moms unit it included the Mult adaptor. I had to work with it to get the unit to work. After replacing caps and the tubes-worked as it should.when you selected “FM stereo” you heard it as stereo if the station had their encoder on and stereo material played thru it to the transmitter. I felt with FM broadcast for a number of years radio broadcast equipment makers sold the stereo encoders to use with their transmitters. The transmitter had to be “direct Fm” not serresoidial as some transmitter exciters used.If the transmitter power stages were all on the stations carrier frequency you could use the direct fm exciter with the stereo encoder-this generated the 10khz pilot frequency needed by the receiver to proper ly sync into the transmitter.then the 19khz was doubled to get 38khz and this was modulated to get the stereo operation. The decoder -mult unit decoded the signal into left-right channels. It also lit the indicator light on your receiver-another function of the 19 kHz pilot tone.
It was 1961, when the Federal Communications Commission approved the Zenith/GE Stereo Multiplex FM system. FM really began becoming mainstream in 1966-1969.
There was a short time in the mid '80s when some US television sets had jacks for an external MPS stereo decoder for roughly the same reasons. But the mass market for NTSC stereo moved so fast that if you blinked, you missed this. Of course it used different parameters from FM MPX, so the old "listen to channel 6 on an FM radio" trick was mono-only.
I can remember equipment that came with schematics inside - usually in an envelope. I'm pretty sure mostly for any service people who might get called in to work on it. It wasn't easy to figure out how to get those pre-internet.
As a late 60's electronics buff, this brings back a flood of memories. I worked on many similar units back in the late 60's, early 70's. I am familiar with all of these tubes and the basics of the designs. Yes, you had to be careful due to the heat and high voltage. 300 +/- was typical of a B+ - higher in TV's of the day. Funny my son who is an electrical engineer, only learned of vaccum tubes in passing from a book. Understandably, most of you reading this probably never saw one, much less work on one. Before the explosion of component stereo systems in the late 60's, large stereo consoles ( some with TV's) were the norm for decent sound from around the mid 50's to mid 60's. My parents had a Magnavox console with a TV from the late 50's that was mono, but sounded great! Magnavox was top shelf back then. A great video and well done. Enjoy!
I have my parents old magnavox system from about the same year or so. It is two separate parts, one with the record changer/ and amp tuner set up and and big speaker set up, and the other part is a movable record storage area and the other speaker set up. It has been in storage for many years, but it was fully functioning and nice looking when stored. Your video has renewed my interest in it. Time to dust it off and see if it wants to live again. Thanks!
That console is a gem! I had a similar labor of love with my uncle's Allen Organ custom console from 1963, which I inherited 2 years ago. Not a beast like the Concert Grand, but close, and as rare if not Moreno. Mine has all Dynaco tube kit (makes sense as Allen was about an hour north of Phili), and a solid walnut cabinet that is gorgeous and showroom condition. Sound wasn't great until I replaced the speaker mid and tweeter drivers, now it's much better. Hated to veer from original, but old paper Jensen drivers weren't cutting it. Now it's glorious sounding, but still "of a time" when big stereo were major furniture purchases and people invested time into enjoying their music collections. Loved your video, I am a little envious, though. That is the holy grail of consoles! Keep it together, maintain and enjoy it, and will only appreciate in value.
That's a lovely specimen! I inherited an Ampex Crescendo console from my grandfather, who also bought it new, and in a similar mid-century modern trim. The story is it was such an extravagant expense that he waited until my grandmother was teaching abroad to make the purchase (luckily she let him keep it!). I completely restored it over a winter about 5 years ago and it's been in service almost every day since then. In mine I intalled a Raspberry Pi with "Raspotify" and a DAC in it, along with an auto turn-on circuit in the preamp/control center, so that it's now a Spotify connect device that automatically turns on when you start playing music to it! I'm guessing you've already found some, but dial cord is available around the internet. Tuner re-stringing can be a major PITA when you're concerned about correct alignment... A few notes and suggestions: -On the amplifiers, the metal box houses the crossover coils L106 and L107, which are used to divide the low and high frequency for the woofer and tweeter sections. -Next time you have the console out, you may want to spend some time cleaning and re-tensioning the contacts in the tube sockets -It would be a good idea to install fuses in each of the components on the AC line input. I typically use the chassis mount twist-lock types I love your videos! Keep up the great work!
Yes, it is the best sounding stereo system I have ever heard, and I have heard some high end high tech gear. I've designed, built and sold a few as well. I replaced the paper and electrolytic capacitors and the power cables to bigger gauge because the ones they had got warm. Draws a good amount of power. I also had the remote control. The music, even though the speakers are close together, sound like they're 10 feet apart. The imaging and sound stage is awesome. I wish I didn't have to sell it. But, I do have the Magnavox I grew up with and got it very very close (I'm an engineer and can do some tweaks to get peak performance). Magnavox engineers were really good that way. Man, I wish I still had it.
My Mom bought one of these when she remarried.I loved this hi-fi this has two bi-amped power amps! I told my Mom when she was going to get rid of the hi-fi Itold her I wanted it. Yes this beast is HEAVY- your set is just like what Mom had. When I saw this video it so reminded me of her set. I removed the amps in hers and recapped-retuned them. I believe she bought hers from a dealer in El Paso Tx.
This must have cost an absolute fortune in its day. Most of the Magnavox tube consoles i can remember from the late 50s early 60s were more of the budget minded stuff which still wasn't cheap. This is a very impressive and rare unit! Thanks for giving us the tour of it! I'll try to keep an eye out for a remote. You have a schematic and know the frequencies of the remote. I have total confidence you could make one. After all you have tackled much bigger and more complicated projects
You know best how to warm the vacuum tube witch's heart, haha! Magnificent Magnavox indeed, the name really does it justice. Just looking at those tube monoblocks gives me a shiver of awe (and fills me with determination). Sorry to hear about your hearing loss. I never realized. Not understanding radio stuff... well, you could say that about me and tube computers, haha! The remote control receiver is such an over-engineered thing for a simple purpose it fulfills, it just blows my mind! I'd keep it disconnected for the time being, until you get or reverse-engineer and make a new remote. The phase inverter used in those magnificent Magnavox monoblocks also blows my mind. Basically, an amplification stage and a voltage divider to an identical amplification stage for the other half of the signal - it has a drawback of introducing asymmetrical distortion. I wonder why a more conventional design (ie long-tailed pair, self-balancing or phase splitter) was not used. Also, driving three tubes from a plate with 220k resistor is rather peculiar here - but sensible for bass and midrange. Equal resistances for plate and grid leak resistors are pretty unheard of as well. As for the other power amp - two 6V6 push pull - it's also that voltage divider and gain stage. It's no FULL BRIDGE RECTIFIER on those 5U4s - it's just a full wave one with two tubes wired in parallel. You could even hot-swap a rectifier tube (but don't do that, okay? :)). Personally I'd try old school wire lacing here, this device simply calls for this lovely old school method :)
Yes, I grew up listening to my Great-Aunts transistorized version (1KWrms Rated). It is a Magnavox unit dating from the late 60's (hard to tell the exact date from the parts).
Magnivox and Motorola used surprisingly sophisticated amplifiers in their upper-echelon hifi consoles, both were known to use biamping on occasion. Some had active center channel speakers as well as Left and Right channels. Both brands used Jensen speakers in some models.
Bi amping was done in the mono Philips Bi-Ampli series of radios. Just normal tabletop radios, as well as more basic consoles.They were typically fitted with two EL84 amplifiers. The later stereo ones continued using the Bi-Ampli trademark but weren't actual proper actively filtered bi-amping, with the exception of the top of the line consoles.
Absolutely superb job and many congratulations! Your dad would be so proud of you for being so dedicated to his baby! Massive valve tech just can’t be beat and unlike anything silicon, will outperform and outlive the same for ever! I still have a number of tube amps from the 70s which have outlived their silicon replacements for decades and decades - I’m a church organ tech and work on all sorts of instruments, from classic pipe organs, some built in the 1850s, through Hammonds and their famous tone wheel generators and still sought after Leslie 122 tube amps, through state of the art digital sampled instruments! Great as the new ones are, with their digital marvels and computer brains, at the end of the day, it’s sound delivery that counts! Here’s where the tube supersedes all!, One instrument I look after has the organ amps in a room of their own! There are 10 units with double 6L6 drivers and HUGE matching transformers. They drive 20 cabinets, each with a 15”, 5” and horn tweeter. The thing shakes the building with bass down to 16 Htz!!!! All clean, no distortion or inter mod distortion, can’t be over driven and sound as good today as when built in 1972……. Other instruments with fancy monolithic power amps have failed spectacularly after only 2-3 years…!!! So man, you’ve done a fantastic thing in keeping the Concert Magnavox in terrific shape, keep her used every day and now have her all cleaned up! I especially loved your reference to Goo Off, or Goof Off, both cleaners I use all the time, and like you, are used for cleaning up older wiring jobs, bringing the cable back to looking like new!! Anyway, enjoyed so much I’ve subscribed and will day join you as a patron - anyone who cares as much as you as about both the equipment and the legacy left you by your dad, is already a terrific friend of mine!!! Take care man, and blessings too!! Adrian in Bermuda (Bermuda Pipe Organ Company Services Limited) ❤️❤️🙏🏻🙏🏻🙏🏻
Those filter networks at the input to the 6 tube and the 2 tube amplifiers are actually your speaker crossovers. Both Magnavox and Motorola built these bi-amp console systems. A line level crossover has many advantages over a passive speaker crossover. But it's also expensive as you need another power amp per channel.
I'm a musician, and recording studio owner, as well as working in IT (sort of) for a day job, this channel is now covering all my interests! Keep up the great work. Sorry to hear about your hearing. 🙁
@@MetalheadAndNerd No. Before the days of FM stereo standardization, many tuners only included a mono audio out and an MPX out. This way, once the standard was established, you could add on an MPX adapter and get stereo without having to buy a new tuner. Once FM stereo tuners started being produced en masse, MPX output jacks disappeared.
@@smwsmwsmw Yep Magnavox was one of the contenders (14) for an FM stereo multiplex system, but they lost out to the Zenith system which is still in use today and uses an L+R signal to feed the "Mono" side of the transmitter for compatibility with a L-R signal on a subcarrier and a 19 kHz "Pilot Tone" to tell the receiver to turn the MPX decoder on. The interesting thing about the L-R signal is that it is AM modulated to save bandwidth and allow more subcarriers to be placed on FM broadcast signals, Musak used to be carried on high-power FM subcarriers and content for the sight impaired from the American Printing House for the Blind is still there, along with RDS (Radio Data System) data and IBOC FM Digital data.
In the 1980's some receivers were again equipped with MPX jacks but this time for AM MPX (AM Stereo) when that trial was over it was the Motorola CQUAM (Compatible Quadrature Amplitude Modulation) system that won out over Harris, Magnavox, and Kahn-Hazeltine.
Amazing to run into this video because when we were young my dad purchased from this well, to do lady a Magnavox hi-fi. This was circuit 1967. Me and my brother and sister listened to all our stuff on it at the time when we were very young. It had two big woofers in it. I still remember sitting on a couch across from the stereo while Eleanor Rigby was on repeat and I was about five years old. And I just marveled like, what is going on here , what the heck was going on. This had to be about 1969. Later on, I would hear other great stereos in the mid 70s as one of my friends dad was an electrician and you how to build them. I recall when I was young that Magnovox stereo was a little bit intimidating to me. The site the sound, The red diode near the bottom, The power of the sound…
I recapped and restored the cabinet on a GE F96 radio from my grandma's house years ago. Had a couple of false starts on it just because the complexity of the unit was pretty up there, but finally got it done. It's the craziest thing to hear it make noise and actually tune a station again. Definitely worth the effort.
Real bi-amplification in a console stereo. That's impressive. Lots of audiophiles set up rigs that they - think - are bi-amplified, but they're really not. This is the real deal. Nice!
LOVE these units. I've been buying/selling consoles, for many years. Picked up a Concert Grand, in 2010; for cheap. I REALLY wanted to keep it, but was very short on space. I would agree with you; one of the best I've ever heard.
Magnavox was the world leader in these entertainment systems; they used MPX (Multiplex) sound equalizers with Folded Corner Klepshorn speakers which gave them the hog quality that they were famous for. Their bass, treble, and high frequency (tweeters) were so well made and insulated inside the exquisite furniture grade cabinets and the amps were just the best in the business. I loved working on them, and wish I had one here I could rebuild and enjoy once again.
I have to admit, being someone that has listened to both during my lifetime, the warmth and depth of a good tube amp beats a digital one any day... BTW... A while back you mentioned how you rotate your projects to be able to not burn out, great choice man... Great choice 🖖😎
Technically all amplifiers are analog, that's simply how loudspeakers work. Some pre-amps have a digital signal processor in them but the processed signal is again analog and goes through an analog power-amp to the speakers. As for tubes vs transistors... that's entirely personal preference. Find what you like and enjoy what you found.
Tubes produce pink noise. Pink noise is just more pleasing to the ears than white noise that transistors produce. Of course good transistorized things do keep the white noise floor very low, so it really doesn't matter. A purist would prefer the perfect reproduction of mathematics of a signal though DSPs and good DACs. But in reality, what matters more is the end result you get, that includes the speakers, the sound box, and every distortion you add up in the chain. Warm pink noise distortion is just better than no distortion, or just noise in practice to the ears. A bit of distortion is good. The irony of people thinking transistorized systems are worse because they just create no distortion to be noticed. They don't have any characteristic sound to be noticed. The better the system is, the less noise you get, which is kind of paradoxical, but what you want from a sound system, in theory, in practice distortion is inevitable. So you better choose what distortion you like more. All the intended distortion put by the studio, and none accidental put by your system, that's the theory, but that's what the studio wants. But that's a preference, you can do whatever you want with your system, even explode its bass and use your own equalizer, or even effects on top of it, after they produced the music, and you bought it, its yours to do whatever you want. Creators are a bit of control freaks sometimes, your "kids" are to the world, not yours. After they're out of your house, you don't control it anymore. Also, tubes are even better when over-driving, no clamping, which is why people think they sound better in amplifiers. You don't over-drive transistors, they just create horrible square waves. None of that matters if you know what you're doing and what you like. Just use what you like. Sometimes that's a valve, sometimes that's a transistor, sometimes its both, sometimes its a mechanical spring (they sound amazing as a chorus "pedal") or other insanity.
Oh my, this brings back memories! As a kid we had the Magnavox entertainment console, which consisted of a 25 inch color TV (which was the equivalent to a big screen today), and the same record player/stereo unit you have. Ours was circa 1963, and was state of the Art for the era. The remote for that unit (and for most Magnavox TV's ect) was the same LOOKING device as the one you showed, except that it worked by ultrasonic vibrations, each button you pressed would emit a very high pitched 'psst', at about the frequency of a dog whistle. The device would recognize that and decode the frequency and perform the function (such as channel change, volume up and down, ect). Worked pretty well except it had one flaw, if you jingled keys or pocket change it would randomly change channels! Us kids used to drive our parents crazy with that...
On an amplifier of this age it is a good idea to check the capacitors that connect between the grid of the output tubes and the triode for leakage. If they ars leaky the output tubes will draw too much current possibly damaging the output transformers and reducing tube life. Other capacitors can also be leaky.
I believe that I saw poly caps in the amps, haven't seen paper and death caps. For the big filtercaps in the cans though, I didn't notice some 450v modern 47ufs and that would be advisable. I once had the fun of letting a can smoking the room up, ugh.
Yes, I am deaf in one ear thanks to the surgeon who took out my brain tumour through that hole! Very sad, to not be able to hear my classical music in stereo any more, but at least I still can hear it !
I’m dying to hear that Magnavox. My Mom had a Sears Silvertone console but I never thought it sounded that good. This from what I hear still sounds great in 2023. Taking one look tells me Magnavox took pleasing their customers very seriously back in the day. It really is an awesome piece.
When I was a kid I had a Magnavox console radio/TV/record player which had similar RF and audio circuits, but nothing anywhere elaborate! I forgot the exact model year, but it was within a few years of 1950. I had no idea Magnavox built anything quite this high end! Amazing!
As someone who did amateur radio for a bit in the past, my thought is that maybe you can run a really long strand of unshielded wire from the magnavox's radio receiver (where one would hook up an antenna) from the inside to outside of your house. The longer the wire, the bigger antenna, and therefore the better chance of picking up any radio stations.
With where he is and the high ground conductivity in North Texas generally, he should have wonderful AM reception at night - heck, in DFW, I can get WSM from nashville at night (though that crazy-town express station on 660 splatters all over it). There should also be pretty good FM reception with an external antenna.
If you did amateur radio, you will know an antenna is not simply a case of long wire. It needs to be tuned to be a multiple of the required wavelength. And unshielded long wire is asking for problems, especially in such an old set where it might become live if a capacitor somewhere in the circuit malfunctions!
@@ernstoud for MW AM Reception (and frankly anything below 10m), a random wire length radio is acceptable. You want a broadband antenna, and no one is is going to go build a half wave or quarter wave antenna for 365m, its just not practical for most people - its either 550 feet or 225 feet of wire. Also, you're not worrying too much about matching either, tbh. I'm not worried about such a line being energized either, the coupling cap is often a mica. Like, if you really wanted you could put an antenna tuner in, but you dont need to care about VSWR if you're not transmitting.
@@ernstouda random wire antenna will work well in this case. A resonant antenna couldn't cover the AM band 550-1600 kcs (kHz hadn't been chosen yet then)
What a beauty. The circuit of the power amps is pretty straightforward. What I haven't seen before is the use of low value inductors L101, L102, L103, L104. Their reactance at audio frequencies will be negligible, especially as they are in the bass section. I guess they are there to prevent parasitic RF oscillations.
If you ever take it apart again you might check the capacitors. As others have mentioned it might be fairly easy to recreate that remote, maybe based around 555 timers. From the glance we got at the schematic it's just a square wave generator hooked to an rf amp. Could be a fun project.... like you need another project :)
being 1962ish it may well have poly or ceramic coupler caps, not waxed paper and they rarely give trouble, only bad thing i can see about it is it uses single cathode bias resistor for the 6V6s in each half of each amplifier, if one 6v6 goes low or open the others will be forced to pass higher anode current reducing their life,
@@zyebormif you look at the schematics you can see an RF oscillator so that thing is actually oscillating at I'm guessing 500kHz to 10Mhz ish modulated with the button tone so Arduino alone no can do
17:56 when dimming your ambient light is the way to "debug" vintage electronics; besides the 2GWatt consumption of that monster, an awesome video showcasing the quality of a past, better, era (when schematics came with every device). Subscribed.
I have one almost like this, my dad got it in late 50s or early 60s. I worked up till 1997. I need to have it looked at.. it is so cool and in killer shape. Its still sitting in the same place.
If you get a "long wire" antenna, you can either connect or couple it to the internal AM antenna. In the evening, I'll bet that radio can pull in AM stations from around the country. (If it can't, something is wrong with it.) I used to listen to AM stations from thousands of miles away on a resurrected console radio and a long wire antenna.
Looking at the drawings it look like the remote control it self is solid state. It uses a 22 1/2 battery. Back in the day I work for a company that done TV repair I done communication radio repair, but would have to go out on some service calls. It seam always to pickup a Magnavox entertainment center that included a tv. They were always on the second floor with no elevator. The good old days. Thanks for the video, always fun.
Also, de-oxit is your friend. I would have use it on all the tube sockets. It not only helps make good connections, it also helps keep them from oxidizing.
Deoxit leaves a lubricant-like residue and should *never* be used on tube sockets. Don't do it. Tube sockets should only be cleaned with no residue solvents such as alcohol. Any residue left behind will cause dust to stick the sockets, which can lead to arcing. Less of a problem with ceramic sockets perhaps but most consoles use cheap phenolic sockets which might even absorb and hold some of the contact cleaner residue. Ive got 55 years of electronics experience to back this up.
@@goodun2974 You could very well be correct at the voltages tubes operate at. I had not considered that. But at lower voltages, that residue actually helps prevent further oxidation, which i would posit (in a lower voltage regiment) to offset the "dust" issue.
@@jeromethiel4323 , the tube pins are used as heat conductors to help cool tge grid, screens, plates etc, and so the pins can probably reach at least 150 degrees when the tubes have been on for a while. Output tube pins in particular are likely to get even hotter than that, and "mineral" oils (petroleum-based) such as the Deoxit base are likely to combine with oxygen at higher temperatures and may tend to congeal. I'll stress this again, do not clean tube sockets with anything that leaves a residue behind. If the sockets are just a little dusty or greasy, you can clean them with alcohol and dental brushes, or paint sprayer tip-cleaning brushes which costs about $6 at Harbor freight and are exactly the same as the supposed tube socket brushes that you buy online from specialty electronics suppliers for $15 or more! If you really want to make sure you get any tarnish and oxidation of the sockets then the miniature tube sockets ( 12AX7, EL84 etc) can be cleaned with a piece of wound guitar string of about .033 to .036 inch diameter, worked back and forth in the contacts like a miniature file or rasp. If you have some kind of Dremel tool or similar motorized tool that is small enough to spin the guitar string, it'll only take about 3 or 4 seconds to clean each tube socket contact!
Man great information for history great program as always, and it is really cool you can turn the retro computer theme to get in something you barely know...great way to lear, mas as always love you work and all you make, it is of great importance for nexts generatios. Saludos from south pacific Costa Rica.
The remote control IS fascinating. It it an AM transmitter of unknown frequency, modulated by 53-95Hz tones. The receiver is a fixed-frequency direct-conversion AM detector, followed by a limiter which removes amplitude variation, and then feeding the now fixed-amplitude tone into a really interesting gadget: Something that looks like a relay, but instead of a moving armature has reeds tuned to the 53-95Hz tones. The reed matching the tone will swing with enough amplitude to hit the contact. It should be easy to replicate, once the center frequency of the receiver has been found.
My Father had a Braun Audio 2 form 1963. Amazing difference to your Grandpa’s behemoth. Interestingtime of innovation form a technical and industrial design point of view. Great to see that yours is still well looked after. My father’s was given to a friend and then lost out of sight. Perhaps it lives on somewhere.
You have the holy grail, that is probably the best console ever made, I had an opportunity to work on one, had to repair one of the amplifiers, bad filter cap, also relubed the turntable. It had an amazing sound. I own several hi end stereo system, and in my opinion I wouldn't mind having one of those in my house. You may need to do some work on the tuner, you should be able to pick up AM at night.
It's not a top of the line model like this beautiful thing, but I do have a magnavox console of the age and man, I can totally attest to these machines being just awesome.
I had a 1959 concert grand unit many years ago. It worked great and was in perfect condition. I can tell you that if you leave the rear subwoofer covers off the bass increases greatly.
I have a Magnavox with the same "head unit" and turntable, But it's a two-piece set, On unit has tuner and amp and turntable and speakers, the other has speakers and record storage. I have the unit on either side of my fireplace. Looks awesome! One day I will restore the electronics.
'62 was a very good year (or early 60's) for some classic console furniture. My parents had a Curtis Mathes console of that period that continued to be a decorative piece of furniture long after the individual components had more or less given out (TV, AM/FM Radio, record changer).
Radio tuner string is a special substance - but mail order is your friend. The manual usually details the installation procedure, since breakage is an expected failure mode.
There were toys that broadcast a radio signal, most directly was "Mr. Microphone". There were also units that plug into a headphone jack so let you hear your device on the main car radio speakers. Digging up one of those would be the easiest way to calibrate the tuning dial. If you're trying to source string, try the stuff used by RC planes. It's Kevlar which does not stretch at all and gives positive repeatable motion, and is available at hobby shops. speakers: When I got my Paradigm Titans in the mid 90's, I found that that just 2 watts would rattle the windows of that room. The 15" subwoofer though, has its own 500W power supply. That would regularly cause screws to loosen throughout the house.
Braided Dacron fishing line is virtually non-stretching and works well as dial string. Monofilament, however, stretches far too much and would never work.
My dad was a fire fighter in the 60s and his “other job” was putting up antenna’s for the local Magnavox dealer. We had a house full of it. TVs, radios; the whole range 😂
The Concert Grand is the holy grail of Magnavox console stereos. 100 watts total power between the 2 bass channels and 2 treble channels. Remote control was radio frequency. That console was $1000 in 1959, which I see was the build date of that unit. Since FM stereo was new, the MPX adapter was an option. Oddly at the time you could opt for FM stereo OR remote control, however the later MPX adapters were smaller and people have CG's with both. I had one in that cabinet style in ebony. It has been passed along to another collector.
Absolutely stunningly beautiful unit! I remember my parents having something similar they bought at Sears. Silvertone brand/model comes to mind. Great work a your stereo!
My dad bought a Realistic brand quadraphonic hifi setup from Radio Shack in the 70's. He and my mom still have the speakers from it hooked up to a modern Yamaha receiver now (for their TV). Weird to think those speakers have gone from playing radio and records in the 70's to playing the audio for likes of Loki, Star Trek: The Lower Decks, etc in 2023. And the thing is, they still sound great and no need for a subwoofer. There's four speakers, each with woofers at least as big as my Polk Audio PSW10 subwoofer.
if a music sounds like an original through an amp speakers and a mic that means the amp and the speakes are amazing and your grandpa made a good buying decision and it outlasted himself that means it was no waste of money
Reminds me of the Zenith my brother has that was in my grandparent’s living room. Though I need to get down to Chicago and do a full check over on it. I think it at minimum needs a new power cord fitted on it.
I can confirm as much: A good stereo system is when all the components fit together. With component stuff, usually they don't quite fit, so the sound is "meh". But with a complete console like this, the manufacturer had all the tuning and adjustment possibilities they could wish for. Apart from that, anything about "good sound" is very much up for the listener to decide. There is no 100% perfect reproduction of sound or visuals anyway, so it's a matter of "pick your favorite distortion" really 😜
I live in Fort Wayne, Indiana. Magnavox relocated here from Chicago in 1931 because we were then the copper wire capital of the US. Their Commercial and Military divisions were located here. We were on Hitler’s list of US cities to bomb during WW 2 because of defense industries like Magnavox. They don’t have much of a presence here now but there is a street still here in an industrial park called Magnavox Way. Thanks for your great video!
Stereo MPX is the multiplexer. It breaks the two channels apart from the broadcast to be amplified independently. And poly filament fishing line works excellently as dial string. Restoration suppliers charge a bleeding fortune for basically the same thing. That is an absolute BEAST of a unit too.
I would likely avoid fishing line, as that would tend to stretch and slip a lot. FM Stereo is a little complex, once you get into it, with L+R and L-R and all tht fun stuff that was done to try and keep it compaitble with mono receivers at the same time as offering stereo, so the multiplexer (MPX) was quite complex too. Some units had the MPX unit built in, some had an input on the back labelled MPX for an optional MPX unit you could buy as an add on.
en.wikipedia.org/wiki/MPX_filter Wikipedia also says it all :)
@@EsotericArctos, braided Dacron fishing line has virtually no stretch and can substitute for dial string.
40 lb stranded@@goodun2974
Standard monofilament can stretch, but I've never had any issues with the braided poly filament stuff. And it's extremely tough stuff too. Funny enough, I've never actually fished with it. When I make a mistake and have to re-string a set a few times with 'genuine' dial string though, the cost can start to sting. Don't always have a diagram to go by. @@EsotericArctos
True bi-amp and those 15" woofers and horn loaded tweeter is still great even for 2023. Good on your grandfather for knowing what he was doing!
It is actually a neat solution as the woofers are way less efficient than the horns, rougly 95dB/m against 105dB/m, therefore a triple push pull set for the woofer nicely will help solving the level. Bi-amping was a good idea in this regard, yet any bi-amping or bi-wiring these days is just introducing extra noisy devices and paralleling over output stages. The setup of this Magnavox set with a nice horn and large woofers is very well sounding by design and modern box speakers are no comparison.
I own a 1961 Concert Grand that I bought from the original owner. He gave me all the documentation and the sales receipt. $1500.00 1961 Dollars, Oh, and he also gave me the demonstration record. Spectacular set
I was born deaf in one ear, I’m a musician, music teacher, and I was enrolled for my masters at American University for their audio technology masters program, you are inspiring! Don’t give up. I also work in IT and have been for 15 years, so your videos are all of the sudden more entertaining and inspiring
This is the holy grail of vintage 60’s hi-fi. Your grand-father knew what he bought, for sure! Very powerful and well designed, he must have been the envy of many! Wow!
He had a lot of money and lived in a big house, there aren't many everyday folks that'd spend as much on a stereo as they wouid a new car
I can confirm, this thing sounds pretty spectacular in person. It's classy looking, and classy sounding.
I just bought new Kef Q350 bookshelf speakers and new subwoofer. If the music at the end was recorded right off this thing, I’d like to hope my new speakers recreated the analog-to-digital-to-analog sound reasonable accurately. Such a beautiful warm tone!
Mi no entender mejor en español grs
I agree with you
What's really cool is a lot of the early remote controls were AUDIO. And the remote itself didn't need batteries. There were a series of metal rods, and when you pushed the button, a little hammer would hit the selected rod and make a ringing sound (very high pitched). This was picked up my a microphone on the system being controlled, and the individual tones would activate relays, that would, in turn, operate the system. Quite often for things like volume up and down, actually controlled a motor that turned the volume knob. So if you clicked the remote, the knob on the TV would turn.
I've seen one of these still in use by it's owner. And yes, this was a tube TV. And the remote worked just fine, although the range was pretty limited. Which wasn't an issue as the picture tubes were small back then, so you usually sat fairly close anyway.
My friends dog would walk past their TV and the rattling of his name tag against his collar would mute the TV!!! :)
/it's/its/
This is why people sometimes still call the remote "the clicker"
@@matthewkriebel7342no it's not
No expense was spared in the design I
Of this. They managed to get three transistors in there, but didn't cheap out with the tubes. Transistors we're probably more expensive at that time though.
I believe the chassis with the sealed bottom is for the FM stereo MPX (multiplex) decoder. That was brand new in 1962 and not all areas had FM stereo broadcasts yet, so it was usually sold as an option. Plus the early tube-based MPX decoders tended to drift, so locating it in a separate chassis away from the heat of the main circuitry helped to improve its performance.
For better AM reception, try connecting a long piece of wire to the external antenna terminal. You should be able to pick up skywave signals from hundreds of miles away at night, even if you don't have not much to listen to locally during the daytime.
I wonder if shango066 is watching this? Hey, vwest!
Yes I think you’re correct. As soon as I noticed that it was a completely shielded chassis, I thought FM. No doubt now that you mentioned the MPX.
Anyone who has never heard one of these quality console stereos simply has no clue how incredible they are. The sound is like nothing you can create from even the best equipment today. A few years ago, I was present at a storage warehouse where an abandoned storage bay was being emptied out. They cranked up one of these on the loading dock and it filled the entire warehouse with the richest, most beautiful sound you could ever imagine.
Wow ...Two massive monoblocks ..Just right there you sold me out!
Amazing, active crossovers and dual mono power amps - I've never seen a console type stereo executed this seriously. Also the tweeter horns are unusual and rather impressive.
That is quite a beast! I have had tube type stereo gear (separate components) for more than forty years. The rig I have now has two monoblock amps that use pairs of 6L6 output tubes that can muster around 30 watts or so before they overload; they feed acoustic labyrinth speakers that work quite well, as long as I am not trying to blow the roof off the house. I wonder how much undistorted power those amps are actually capable of under worst-case conditions-- the arrangement with the separate bass channel is a very practical way to allow "fudging" the output transformers in the midrange-treble amplifiers since filtering out the bass frequencies BEFORE the power amps would sidestep the intermodulation distortion that would result with an inadequate output transformer being badly overloaded at low frequencies.
At the time, Motorola was noted for their consoles that were skimped and got away with it by doing pre-power-amplifier crossovers.
Magnavox is known originally for its horns. They used them up into the ‘70’s in their larger console units. Some had dual horns.
@donleamon8653 we had an Astro-Sonic when I was a youngster-- it paled in comparison to the Yamaha receiver and Advent speakers that replaced it in the late seventies. . .
Those horns are not for me
Tweeter horns may be ElectroVoice
I like the magnavox coat of arms. Gives it an classy vibe. I can imagine it looking good in an elegant drawing room in a manor. "Jeeves, please be good enough to turn the wireless on to the BBC. Mr Churchill is about to speak."
Good Lord, what a beast! Dual bi-amped monoblock power amplifiers in a home console system in 1962? I never knew there was such a thing! And those horns and 15" woofers look like they would be more at home in a small concert venue! That's a machine to cherish, indeed.
I'm not saying it doesn't sound good but 15" woofers back then didn't have a lot of movement. They were usually quite stiff due to the paper surrounds.
@@bertroost1675 That's certainly true, but then I don't think small concert venues had the SPLs or low-end coverage they have today. I stand by my claim that I haven't seen many, if any, other 15" woofers in loudspeakers intended for home use in the early 1960s.
@@danmenes3143 I have a different Magnavox console that also has 15" woofers. They're placed sideways so the console could be smaller.
@@bertroost1675
They were that way because of the usual low amplifier power. They were tuned for efficiency, not low bass extension/spl. Although 'long throw' woofers in sealed cabinets were around already - but only in standalone speakers (mainly Acoustic Research and KLH models). Pro speakers for venues would have mainly used all sorts of horns at the time.
@@danmenes3143
It was quite common for those large 'Texas sized' consoles to have 12" or 15" woofers. In the later years, when they got cheapened, as component stereos became more common and people wouldn't spend as much on a console, this wasn't the case anymore. Sometimes you find 6.5”s with puny amps in huge cabinets.
My friend's parents got a console stereo/TV. When his parents left him home alone one Saturday, he had it cranked so loud, and it sounded so good, that I literally thought it was a live band playing a party until I ran down the street and saw it was just their stereo! Horns and high compliance speakers are incredibly efficient and play really loud.
MPX means "Multiplex" as already mentioned. Early FM tuners and receivers received a monophonic signal. Around 1960 (not sure exactly when) the decision was made to allow some stations to broadcast in stereo. But this had to be done in such a way that a mono receiver would still work OK. There were several competing designs, so until the dust settled, some mfrs brought out the necessary signal to be fed (optionally) to an external "multiplex decoder" which produced stereo outputs. This is the MPX jack on your unit, and implies that it does not have an internal multiplex decoder. Probably units made a year or two after this one had the stereo decoder built-in.
Oops! Looks like this unit not only had MPX out, but also inputs for the externally decoded stereo signals, so that FM Stereo could be selected from the front panel.
The FCC approved the current FM multiplex system in late 1961. Magnavox sold the decoder as an extra cost option until about 1963. Decoders were integrated into the receivers after 1963 when Magnavox went solid state. The decoders show up frequently on EBay.
In my Moms unit it included the Mult adaptor. I had to work with it to get the unit to work. After replacing caps and the tubes-worked as it should.when you selected “FM stereo” you heard it as stereo if the station had their encoder on and stereo material played thru it to the transmitter. I felt with FM broadcast for a number of years radio broadcast equipment makers sold the stereo encoders to use with their transmitters. The transmitter had to be “direct Fm” not serresoidial as some transmitter exciters used.If the transmitter power stages were all on the stations carrier frequency you could use the direct fm exciter with the stereo encoder-this generated the 10khz pilot frequency needed by the receiver to proper ly sync into the transmitter.then the 19khz was doubled to get 38khz and this was modulated to get the stereo operation. The decoder -mult unit decoded the signal into left-right channels. It also lit the indicator light on your receiver-another function of the 19 kHz pilot tone.
It was 1961, when the Federal Communications Commission approved the Zenith/GE Stereo Multiplex FM system. FM really began becoming mainstream in 1966-1969.
There was a short time in the mid '80s when some US television sets had jacks for an external MPS stereo decoder for roughly the same reasons. But the mass market for NTSC stereo moved so fast that if you blinked, you missed this.
Of course it used different parameters from FM MPX, so the old "listen to channel 6 on an FM radio" trick was mono-only.
All home electronics should come with a schematic like that. Its like they expected you to repair it if needed. What a time.
I can remember equipment that came with schematics inside - usually in an envelope. I'm pretty sure mostly for any service people who might get called in to work on it. It wasn't easy to figure out how to get those pre-internet.
Even in the 1970s many Radio Shack products included a schematic in the owner's manual. Very thoughtful.
As a late 60's electronics buff, this brings back a flood of memories. I worked on many similar units back in the late 60's, early 70's. I am familiar with all of these tubes and the basics of the designs. Yes, you had to be careful due to the heat and high voltage. 300 +/- was typical of a B+ - higher in TV's of the day. Funny my son who is an electrical engineer, only learned of vaccum tubes in passing from a book. Understandably, most of you reading this probably never saw one, much less work on one. Before the explosion of component stereo systems in the late 60's, large stereo consoles ( some with TV's) were the norm for decent sound from around the mid 50's to mid 60's. My parents had a Magnavox console with a TV from the late 50's that was mono, but sounded great! Magnavox was top shelf back then. A great video and well done. Enjoy!
I have my parents old magnavox system from about the same year or so. It is two separate parts, one with the record changer/ and amp tuner set up and and big speaker set up, and the other part is a movable record storage area and the other speaker set up. It has been in storage for many years, but it was fully functioning and nice looking when stored. Your video has renewed my interest in it. Time to dust it off and see if it wants to live again. Thanks!
That console is a gem! I had a similar labor of love with my uncle's Allen Organ custom console from 1963, which I inherited 2 years ago. Not a beast like the Concert Grand, but close, and as rare if not Moreno. Mine has all Dynaco tube kit (makes sense as Allen was about an hour north of Phili), and a solid walnut cabinet that is gorgeous and showroom condition. Sound wasn't great until I replaced the speaker mid and tweeter drivers, now it's much better. Hated to veer from original, but old paper Jensen drivers weren't cutting it. Now it's glorious sounding, but still "of a time" when big stereo were major furniture purchases and people invested time into enjoying their music collections. Loved your video, I am a little envious, though. That is the holy grail of consoles! Keep it together, maintain and enjoy it, and will only appreciate in value.
That thing is super cool! Back when stereos were part of the living room furniture! Love it!!
That's a lovely specimen! I inherited an Ampex Crescendo console from my grandfather, who also bought it new, and in a similar mid-century modern trim. The story is it was such an extravagant expense that he waited until my grandmother was teaching abroad to make the purchase (luckily she let him keep it!). I completely restored it over a winter about 5 years ago and it's been in service almost every day since then. In mine I intalled a Raspberry Pi with "Raspotify" and a DAC in it, along with an auto turn-on circuit in the preamp/control center, so that it's now a Spotify connect device that automatically turns on when you start playing music to it!
I'm guessing you've already found some, but dial cord is available around the internet. Tuner re-stringing can be a major PITA when you're concerned about correct alignment...
A few notes and suggestions:
-On the amplifiers, the metal box houses the crossover coils L106 and L107, which are used to divide the low and high frequency for the woofer and tweeter sections.
-Next time you have the console out, you may want to spend some time cleaning and re-tensioning the contacts in the tube sockets
-It would be a good idea to install fuses in each of the components on the AC line input. I typically use the chassis mount twist-lock types
I love your videos! Keep up the great work!
Yes, it is the best sounding stereo system I have ever heard, and I have heard some high end high tech gear. I've designed, built and sold a few as well. I replaced the paper and electrolytic capacitors and the power cables to bigger gauge because the ones they had got warm. Draws a good amount of power. I also had the remote control. The music, even though the speakers are close together, sound like they're 10 feet apart. The imaging and sound stage is awesome. I wish I didn't have to sell it. But, I do have the Magnavox I grew up with and got it very very close (I'm an engineer and can do some tweaks to get peak performance). Magnavox engineers were really good that way. Man, I wish I still had it.
My grandparents had one, and my brother now has it at his house, and it does sound amazing!
My Mom bought one of these when she remarried.I loved this hi-fi this has two bi-amped power amps! I told my Mom when she was going to get rid of the hi-fi Itold her I wanted it. Yes this beast is HEAVY- your set is just like what Mom had. When I saw this video it so reminded me of her set. I removed the amps in hers and recapped-retuned them. I believe she bought hers from a dealer in El Paso Tx.
This must have cost an absolute fortune in its day. Most of the Magnavox tube consoles i can remember from the late 50s early 60s were more of the budget minded stuff which still wasn't cheap. This is a very impressive and rare unit! Thanks for giving us the tour of it! I'll try to keep an eye out for a remote. You have a schematic and know the frequencies of the remote. I have total confidence you could make one. After all you have tackled much bigger and more complicated projects
Likely did. My grandfather bought a Zenith MK2618 in 1962. It costed $475. That's over $3700 today.
You know best how to warm the vacuum tube witch's heart, haha! Magnificent Magnavox indeed, the name really does it justice. Just looking at those tube monoblocks gives me a shiver of awe (and fills me with determination).
Sorry to hear about your hearing loss. I never realized.
Not understanding radio stuff... well, you could say that about me and tube computers, haha!
The remote control receiver is such an over-engineered thing for a simple purpose it fulfills, it just blows my mind! I'd keep it disconnected for the time being, until you get or reverse-engineer and make a new remote.
The phase inverter used in those magnificent Magnavox monoblocks also blows my mind. Basically, an amplification stage and a voltage divider to an identical amplification stage for the other half of the signal - it has a drawback of introducing asymmetrical distortion. I wonder why a more conventional design (ie long-tailed pair, self-balancing or phase splitter) was not used. Also, driving three tubes from a plate with 220k resistor is rather peculiar here - but sensible for bass and midrange. Equal resistances for plate and grid leak resistors are pretty unheard of as well. As for the other power amp - two 6V6 push pull - it's also that voltage divider and gain stage.
It's no FULL BRIDGE RECTIFIER on those 5U4s - it's just a full wave one with two tubes wired in parallel. You could even hot-swap a rectifier tube (but don't do that, okay? :)).
Personally I'd try old school wire lacing here, this device simply calls for this lovely old school method :)
Technically It's a Full Wave Center Tap Rectifier, with the Rectifier Tubes in parallel to double the current capability..
what a beautiful piece of electrical appliance with its furniture. you lucky lucky lucky lucky man !
I love seeing one of these that isn't fully solid state and as near mint as it gets it's truly a gem that I hope you can treasure forever
WHAT! Hold on... dual mono and ACTIVE bi-amping? Heck! Did anything else exist like this, at least consumer wise back then? What a beast.
Yes, I grew up listening to my Great-Aunts transistorized version (1KWrms Rated). It is a Magnavox unit dating from the late 60's (hard to tell the exact date from the parts).
Magnivox and Motorola used surprisingly sophisticated amplifiers in their upper-echelon hifi consoles, both were known to use biamping on occasion. Some had active center channel speakers as well as Left and Right channels. Both brands used Jensen speakers in some models.
Bi amping was done in the mono Philips Bi-Ampli series of radios. Just normal tabletop radios, as well as more basic consoles.They were typically fitted with two EL84 amplifiers. The later stereo ones continued using the Bi-Ampli trademark but weren't actual proper actively filtered bi-amping, with the exception of the top of the line consoles.
Absolutely superb job and many congratulations! Your dad would be so proud of you for being so dedicated to his baby! Massive valve tech just can’t be beat and unlike anything silicon, will outperform and outlive the same for ever! I still have a number of tube amps from the 70s which have outlived their silicon replacements for decades and decades - I’m a church organ tech and work on all sorts of instruments, from classic pipe organs, some built in the 1850s, through Hammonds and their famous tone wheel generators and still sought after Leslie 122 tube amps, through state of the art digital sampled instruments! Great as the new ones are, with their digital marvels and computer brains, at the end of the day, it’s sound delivery that counts! Here’s where the tube supersedes all!, One instrument I look after has the organ amps in a room of their own! There are 10 units with double 6L6 drivers and HUGE matching transformers. They drive 20 cabinets, each with a 15”, 5” and horn tweeter. The thing shakes the building with bass down to 16 Htz!!!! All clean, no distortion or inter mod distortion, can’t be over driven and sound as good today as when built in 1972…….
Other instruments with fancy monolithic power amps have failed spectacularly after only 2-3 years…!!!
So man, you’ve done a fantastic thing in keeping the Concert Magnavox in terrific shape, keep her used every day and now have her all cleaned up!
I especially loved your reference to Goo Off, or Goof Off, both cleaners I use all the time, and like you, are used for cleaning up older wiring jobs, bringing the cable back to looking like new!!
Anyway, enjoyed so much I’ve subscribed and will day join you as a patron - anyone who cares as much as you as about both the equipment and the legacy left you by your dad, is already a terrific friend of mine!!!
Take care man, and blessings too!!
Adrian in Bermuda (Bermuda Pipe Organ Company Services Limited) ❤️❤️🙏🏻🙏🏻🙏🏻
Those filter networks at the input to the 6 tube and the 2 tube amplifiers are actually your speaker crossovers. Both Magnavox and Motorola built these bi-amp console systems. A line level crossover has many advantages over a passive speaker crossover. But it's also expensive as you need another power amp per channel.
I'm a musician, and recording studio owner, as well as working in IT (sort of) for a day job, this channel is now covering all my interests! Keep up the great work. Sorry to hear about your hearing. 🙁
What a beautiful piece of audio equipment!! MPX stands for multiplexer, meant to be connected to an external fm stereo decoder.
Was using an external stereo decoder the 50' equivalent of using an external DAC ("because of course I hear the difference!")?
@@MetalheadAndNerd No. Before the days of FM stereo standardization, many tuners only included a mono audio out and an MPX out. This way, once the standard was established, you could add on an MPX adapter and get stereo without having to buy a new tuner. Once FM stereo tuners started being produced en masse, MPX output jacks disappeared.
@@smwsmwsmw Yep Magnavox was one of the contenders (14) for an FM stereo multiplex system, but they lost out to the Zenith system which is still in use today and uses an L+R signal to feed the "Mono" side of the transmitter for compatibility with a L-R signal on a subcarrier and a 19 kHz "Pilot Tone" to tell the receiver to turn the MPX decoder on. The interesting thing about the L-R signal is that it is AM modulated to save bandwidth and allow more subcarriers to be placed on FM broadcast signals, Musak used to be carried on high-power FM subcarriers and content for the sight impaired from the American Printing House for the Blind is still there, along with RDS (Radio Data System) data and IBOC FM Digital data.
In the 1980's some receivers were again equipped with MPX jacks but this time for AM MPX (AM Stereo) when that trial was over it was the Motorola CQUAM (Compatible Quadrature Amplitude Modulation) system that won out over Harris, Magnavox, and Kahn-Hazeltine.
@@mspysu79 You're right. Surprised I forgot about that, AM stereo having had such a huge impact on society and all.
/s
Extreme beauty in the desing. Congrats for the unique piece of equipment. From Mexico.
Amazing to run into this video because when we were young my dad purchased from this well, to do lady a Magnavox hi-fi. This was circuit 1967. Me and my brother and sister listened to all our stuff on it at the time when we were very young. It had two big woofers in it. I still remember sitting on a couch across from the stereo while Eleanor Rigby was on repeat and I was about five years old. And I just marveled like, what is going on here , what the heck was going on. This had to be about 1969. Later on, I would hear other great stereos in the mid 70s as one of my friends dad was an electrician and you how to build them. I recall when I was young that Magnovox stereo was a little bit intimidating to me. The site the sound, The red diode near the bottom, The power of the sound…
I recapped and restored the cabinet on a GE F96 radio from my grandma's house years ago. Had a couple of false starts on it just because the complexity of the unit was pretty up there, but finally got it done. It's the craziest thing to hear it make noise and actually tune a station again. Definitely worth the effort.
What a lovely piece of history!
Real bi-amplification in a console stereo. That's impressive. Lots of audiophiles set up rigs that they - think - are bi-amplified, but they're really not. This is the real deal. Nice!
@StringerNews1 I used to have one of those crossovers! I used in in my sound reinforcement system back in the mid-late 80's. My lord, I'm old.
LOVE these units. I've been buying/selling consoles, for many years. Picked up a Concert Grand, in 2010; for cheap. I REALLY wanted to keep it, but was very short on space. I would agree with you; one of the best I've ever heard.
Thanks grandpa!
epic stereo, big and beautiful and you know its there.
Magnavox was the world leader in these entertainment systems; they used MPX (Multiplex) sound equalizers with Folded Corner Klepshorn speakers which gave them the hog quality that they were famous for. Their bass, treble, and high frequency (tweeters) were so well made and insulated inside the exquisite furniture grade cabinets and the amps were just the best in the business. I loved working on them, and wish I had one here I could rebuild and enjoy once again.
I have to admit, being someone that has listened to both during my lifetime, the warmth and depth of a good tube amp beats a digital one any day... BTW... A while back you mentioned how you rotate your projects to be able to not burn out, great choice man...
Great choice 🖖😎
Technically all amplifiers are analog, that's simply how loudspeakers work. Some pre-amps have a digital signal processor in them but the processed signal is again analog and goes through an analog power-amp to the speakers.
As for tubes vs transistors... that's entirely personal preference. Find what you like and enjoy what you found.
@@vinny142there are class d power amps
Tubes produce pink noise. Pink noise is just more pleasing to the ears than white noise that transistors produce. Of course good transistorized things do keep the white noise floor very low, so it really doesn't matter.
A purist would prefer the perfect reproduction of mathematics of a signal though DSPs and good DACs. But in reality, what matters more is the end result you get, that includes the speakers, the sound box, and every distortion you add up in the chain.
Warm pink noise distortion is just better than no distortion, or just noise in practice to the ears. A bit of distortion is good. The irony of people thinking transistorized systems are worse because they just create no distortion to be noticed. They don't have any characteristic sound to be noticed. The better the system is, the less noise you get, which is kind of paradoxical, but what you want from a sound system, in theory, in practice distortion is inevitable. So you better choose what distortion you like more.
All the intended distortion put by the studio, and none accidental put by your system, that's the theory, but that's what the studio wants.
But that's a preference, you can do whatever you want with your system, even explode its bass and use your own equalizer, or even effects on top of it, after they produced the music, and you bought it, its yours to do whatever you want. Creators are a bit of control freaks sometimes, your "kids" are to the world, not yours. After they're out of your house, you don't control it anymore.
Also, tubes are even better when over-driving, no clamping, which is why people think they sound better in amplifiers. You don't over-drive transistors, they just create horrible square waves.
None of that matters if you know what you're doing and what you like.
Just use what you like. Sometimes that's a valve, sometimes that's a transistor, sometimes its both, sometimes its a mechanical spring (they sound amazing as a chorus "pedal") or other insanity.
Thanks for the great explanations everyone.
Oh my, this brings back memories! As a kid we had the Magnavox entertainment console, which consisted of a 25 inch color TV (which was the equivalent to a big screen today), and the same record player/stereo unit you have. Ours was circa 1963, and was state of the Art for the era. The remote for that unit (and for most Magnavox TV's ect) was the same LOOKING device as the one you showed, except that it worked by ultrasonic vibrations, each button you pressed would emit a very high pitched 'psst', at about the frequency of a dog whistle. The device would recognize that and decode the frequency and perform the function (such as channel change, volume up and down, ect). Worked pretty well except it had one flaw, if you jingled keys or pocket change it would randomly change channels! Us kids used to drive our parents crazy with that...
I've seen a lot of stereograms but this is one of the most high end ones I've encountered. They are usually a single chassis. Very nice unit.
This was AWESOME. I love old audio technology, great video😁👍
On an amplifier of this age it is a good idea to check the capacitors that connect between the grid of the output tubes and the triode for leakage. If they ars leaky the output tubes will draw too much current possibly damaging the output transformers and reducing tube life. Other capacitors can also be leaky.
I believe that I saw poly caps in the amps, haven't seen paper and death caps. For the big filtercaps in the cans though, I didn't notice some 450v modern 47ufs and that would be advisable. I once had the fun of letting a can smoking the room up, ugh.
Yes, I am deaf in one ear thanks to the surgeon who took out my brain tumour through that hole! Very sad, to not be able to hear my classical music in stereo any more, but at least I still can hear it !
Ooo I bet the sound coming out of that stereo is so rich and warm!!
I’m dying to hear that Magnavox. My Mom had a Sears Silvertone console but I never thought it sounded that good. This from what I hear still sounds great in 2023. Taking one look tells me Magnavox took pleasing their customers very seriously back in the day. It really is an awesome piece.
Back in the period my parents bought a beautiful new Philips like this. Very beautiful woodwork with large radius front corners.
When I was a kid I had a Magnavox console radio/TV/record player which had similar RF and audio circuits, but nothing anywhere elaborate! I forgot the exact model year, but it was within a few years of 1950. I had no idea Magnavox built anything quite this high end! Amazing!
As someone who did amateur radio for a bit in the past, my thought is that maybe you can run a really long strand of unshielded wire from the magnavox's radio receiver (where one would hook up an antenna) from the inside to outside of your house. The longer the wire, the bigger antenna, and therefore the better chance of picking up any radio stations.
With where he is and the high ground conductivity in North Texas generally, he should have wonderful AM reception at night - heck, in DFW, I can get WSM from nashville at night (though that crazy-town express station on 660 splatters all over it).
There should also be pretty good FM reception with an external antenna.
If you did amateur radio, you will know an antenna is not simply a case of long wire. It needs to be tuned to be a multiple of the required wavelength. And unshielded long wire is asking for problems, especially in such an old set where it might become live if a capacitor somewhere in the circuit malfunctions!
@@ernstoud for MW AM Reception (and frankly anything below 10m), a random wire length radio is acceptable. You want a broadband antenna, and no one is is going to go build a half wave or quarter wave antenna for 365m, its just not practical for most people - its either 550 feet or 225 feet of wire. Also, you're not worrying too much about matching either, tbh. I'm not worried about such a line being energized either, the coupling cap is often a mica.
Like, if you really wanted you could put an antenna tuner in, but you dont need to care about VSWR if you're not transmitting.
Yeah, that way he could listen to propaganda, great idea.
@@ernstouda random wire antenna will work well in this case. A resonant antenna couldn't cover the AM band 550-1600 kcs (kHz hadn't been chosen yet then)
Mr. Carlson's Lab has several tuning and adjustment videos for receivers. All you need is the schematic and frequency generator.
What a beauty. The circuit of the power amps is pretty straightforward. What I haven't seen before is the use of low value inductors L101, L102, L103, L104. Their reactance at audio frequencies will be negligible, especially as they are in the bass section. I guess they are there to prevent parasitic RF oscillations.
Thise consoles sounded spectacular for what they were. Excellent!
If you ever take it apart again you might check the capacitors. As others have mentioned it might be fairly easy to recreate that remote, maybe based around 555 timers. From the glance we got at the schematic it's just a square wave generator hooked to an rf amp. Could be a fun project.... like you need another project :)
being 1962ish it may well have poly or ceramic coupler caps, not waxed paper and they rarely give trouble, only bad thing i can see about it is it uses single cathode bias resistor for the 6V6s in each half of each amplifier, if one 6v6 goes low or open the others will be forced to pass higher anode current reducing their life,
At those frequencies he could probably just toggle the pins of an Arduino or similar lol. Maximum lazy
@@zyebormif you look at the schematics you can see an RF oscillator so that thing is actually oscillating at I'm guessing 500kHz to 10Mhz ish modulated with the button tone so Arduino alone no can do
That would be an amazing project! :O
I agree with everyone else: build a remote of your own. It would be cute to build a tube remote!
We had one about 2/3 as tall. That sliding door at the top brings back memories! I donated it to charity years ago.
This looks like a good opportunity for a collaborative video with Mr. Carlson's Lab!
...or with Uncle Doug - with an added benefit of him being located in Texas :)
17:56 when dimming your ambient light is the way to "debug" vintage electronics; besides the 2GWatt consumption of that monster, an awesome video showcasing the quality of a past, better, era (when schematics came with every device).
Subscribed.
EXCELLENT! Thank you. It´s a beautiful machine.
Gorgeous console. I sure wouldn't mind owning one! The construction is audiophile-level with the quad amps. I bet it sounds even better in person.
I have one almost like this, my dad got it in late 50s or early 60s. I worked up till 1997. I need to have it looked at.. it is so cool and in killer shape. Its still sitting in the same place.
If you get a "long wire" antenna, you can either connect or couple it to the internal AM antenna. In the evening, I'll bet that radio can pull in AM stations from around the country. (If it can't, something is wrong with it.) I used to listen to AM stations from thousands of miles away on a resurrected console radio and a long wire antenna.
Nothing can beat quality analog sound.
Looking at the drawings it look like the remote control it self is solid state. It uses a 22 1/2 battery. Back in the day I work for a company that done TV repair I done communication radio repair, but would have to go out on some service calls. It seam always to pickup a Magnavox entertainment center that included a tv. They were always on the second floor with no elevator. The good old days. Thanks for the video, always fun.
Also, de-oxit is your friend. I would have use it on all the tube sockets. It not only helps make good connections, it also helps keep them from oxidizing.
Interesting to see an octal socket with contact problems. I am more used to novals having contact problems
That's what I was thinking.
Deoxit leaves a lubricant-like residue and should *never* be used on tube sockets. Don't do it. Tube sockets should only be cleaned with no residue solvents such as alcohol. Any residue left behind will cause dust to stick the sockets, which can lead to arcing. Less of a problem with ceramic sockets perhaps but most consoles use cheap phenolic sockets which might even absorb and hold some of the contact cleaner residue. Ive got 55 years of electronics experience to back this up.
@@goodun2974 You could very well be correct at the voltages tubes operate at. I had not considered that. But at lower voltages, that residue actually helps prevent further oxidation, which i would posit (in a lower voltage regiment) to offset the "dust" issue.
@@jeromethiel4323 , the tube pins are used as heat conductors to help cool tge grid, screens, plates etc, and so the pins can probably reach at least 150 degrees when the tubes have been on for a while. Output tube pins in particular are likely to get even hotter than that, and "mineral" oils (petroleum-based) such as the Deoxit base are likely to combine with oxygen at higher temperatures and may tend to congeal. I'll stress this again, do not clean tube sockets with anything that leaves a residue behind.
If the sockets are just a little dusty or greasy, you can clean them with alcohol and dental brushes, or paint sprayer tip-cleaning brushes which costs about $6 at Harbor freight and are exactly the same as the supposed tube socket brushes that you buy online from specialty electronics suppliers for $15 or more!
If you really want to make sure you get any tarnish and oxidation of the sockets then the miniature tube sockets ( 12AX7, EL84 etc) can be cleaned with a piece of wound guitar string of about .033 to .036 inch diameter, worked back and forth in the contacts like a miniature file or rasp. If you have some kind of Dremel tool or similar motorized tool that is small enough to spin the guitar string, it'll only take about 3 or 4 seconds to clean each tube socket contact!
Man great information for history great program as always, and it is really cool you can turn the retro computer theme to get in something you barely know...great way to lear, mas as always love you work and all you make, it is of great importance for nexts generatios. Saludos from south pacific Costa Rica.
The remote control IS fascinating. It it an AM transmitter of unknown frequency, modulated by 53-95Hz tones. The receiver is a fixed-frequency direct-conversion AM detector, followed by a limiter which removes amplitude variation, and then feeding the now fixed-amplitude tone into a really interesting gadget: Something that looks like a relay, but instead of a moving armature has reeds tuned to the 53-95Hz tones. The reed matching the tone will swing with enough amplitude to hit the contact.
It should be easy to replicate, once the center frequency of the receiver has been found.
My Father had a Braun Audio 2 form 1963. Amazing difference to your Grandpa’s behemoth. Interestingtime of innovation form a technical and industrial design point of view. Great to see that yours is still well looked after. My father’s was given to a friend and then lost out of sight. Perhaps it lives on somewhere.
That's a wonderful console and in really good condition too. I bet it sounds great.
You have the holy grail, that is probably the best console ever made, I had an opportunity to work on one, had to repair one of the amplifiers, bad filter cap, also relubed the turntable. It had an amazing sound. I own several hi end stereo system, and in my opinion I wouldn't mind having one of those in my house. You may need to do some work on the tuner, you should be able to pick up AM at night.
1962 is the year I was born. Wow what a cool radio.
It looks like you could make a remote pretty easily, I know you want an original one to go with the unit, but it'd be cool to see it work remotely
I suppose the trickiest thing would be figuring out the right antenna coil to use, but hopefully there's a hint in the manual or schematic
Amazing !! I love this stuff. Had a couple tube consoles myself over the years.
It's not a top of the line model like this beautiful thing, but I do have a magnavox console of the age and man, I can totally attest to these machines being just awesome.
What a beast , what a quality construction also ,….would love to have one of this
Great work for an impressive product!
I had a 1959 concert grand unit many years ago.
It worked great and was in perfect condition.
I can tell you that if you leave the rear subwoofer covers off the bass increases greatly.
I have a Magnavox with the same "head unit" and turntable, But it's a two-piece set, On unit has tuner and amp and turntable and speakers, the other has speakers and record storage. I have the unit on either side of my fireplace. Looks awesome! One day I will restore the electronics.
'62 was a very good year (or early 60's) for some classic console furniture. My parents had a Curtis Mathes console of that period that continued to be a decorative piece of furniture long after the individual components had more or less given out (TV, AM/FM Radio, record changer).
Radio tuner string is a special substance - but mail order is your friend. The manual usually details the installation procedure, since breakage is an expected failure mode.
There were toys that broadcast a radio signal, most directly was "Mr. Microphone". There were also units that plug into a headphone jack so let you hear your device on the main car radio speakers. Digging up one of those would be the easiest way to calibrate the tuning dial. If you're trying to source string, try the stuff used by RC planes. It's Kevlar which does not stretch at all and gives positive repeatable motion, and is available at hobby shops.
speakers: When I got my Paradigm Titans in the mid 90's, I found that that just 2 watts would rattle the windows of that room. The 15" subwoofer though, has its own 500W power supply. That would regularly cause screws to loosen throughout the house.
Braided Dacron fishing line is virtually non-stretching and works well as dial string. Monofilament, however, stretches far too much and would never work.
Amazing that the small wholes in the back cover seem to be the only way to get rid of the heat. Thanks!
It's truly a work of art... ☮🔥 ... 🌎☮NOW!
My dad was a fire fighter in the 60s and his “other job” was putting up antenna’s for the local Magnavox dealer. We had a house full of it. TVs, radios; the whole range 😂
The Concert Grand is the holy grail of Magnavox console stereos. 100 watts total power between the 2 bass channels and 2 treble channels. Remote control was radio frequency. That console was $1000 in 1959, which I see was the build date of that unit. Since FM stereo was new, the MPX adapter was an option. Oddly at the time you could opt for FM stereo OR remote control, however the later MPX adapters were smaller and people have CG's with both. I had one in that cabinet style in ebony. It has been passed along to another collector.
Awesome! Anything from this vintage will be just fine with me!
Absolutely stunningly beautiful unit! I remember my parents having something similar they bought at Sears. Silvertone brand/model comes to mind. Great work a your stereo!
My dad bought a Realistic brand quadraphonic hifi setup from Radio Shack in the 70's. He and my mom still have the speakers from it hooked up to a modern Yamaha receiver now (for their TV). Weird to think those speakers have gone from playing radio and records in the 70's to playing the audio for likes of Loki, Star Trek: The Lower Decks, etc in 2023. And the thing is, they still sound great and no need for a subwoofer. There's four speakers, each with woofers at least as big as my Polk Audio PSW10 subwoofer.
What a lovely machine, and an interesting use!
I'd love a stereo console like that.
if a music sounds like an original through an amp speakers and a mic that means the amp and the speakes are amazing and your grandpa made a good buying decision and it outlasted himself that means it was no waste of money
i see for first time so one wonderful Stereo Equipment Absolute phandastic
I have this exact Magnavox, with a working remote control.
A stunning bit of kit.
Reminds me of the Zenith my brother has that was in my grandparent’s living room. Though I need to get down to Chicago and do a full check over on it. I think it at minimum needs a new power cord fitted on it.
I can confirm as much: A good stereo system is when all the components fit together. With component stuff, usually they don't quite fit, so the sound is "meh". But with a complete console like this, the manufacturer had all the tuning and adjustment possibilities they could wish for. Apart from that, anything about "good sound" is very much up for the listener to decide. There is no 100% perfect reproduction of sound or visuals anyway, so it's a matter of "pick your favorite distortion" really 😜
This may have been the nicest console Magnevox ever made. Take very good care of this, as it will increase in value a lot over the next few years.
That is a beautiful piece!
I live in Fort Wayne, Indiana. Magnavox relocated here from Chicago in 1931 because we were then the copper wire capital of the US. Their Commercial and Military divisions were located here. We were on Hitler’s list of US cities to bomb during WW 2 because of defense industries like Magnavox. They don’t have much of a presence here now but there is a street still here in an industrial park called Magnavox Way. Thanks for your great video!