1956 National Aztec Guitar Amplifier

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  • เผยแพร่เมื่อ 23 ธ.ค. 2024

ความคิดเห็น • 101

  • @CC-te5zf
    @CC-te5zf 2 ปีที่แล้ว

    As I learn so much from you about all of these wonderful amps, I envision a museum where today's kids get to learn about where they can meet the ancestors of their favorite gadgets. You could have some amps setup safely that they could play a guitar thru, maybe bins of components that they could touch and look at, etc. Maybe something like that exists and I'm just unaware. I remember the bug that bit me as a kid. I remember my Grandmother replacing tubes in her television. Nowadays nothing gets worked on - it just gets thrown away or recycled. I learned how to fix stuff as a kid by watching those around me. An amp museum would be a great place to plant some seeds out there for the next generation of enthusiasts.

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว +1

      An excellent idea, Chad. I wonder if today's cell phone addicted youth would support such an endeavor ??

    • @CC-te5zf
      @CC-te5zf 2 ปีที่แล้ว +1

      @@UncleDoug Good question!

  • @PandemoniumMeltDown
    @PandemoniumMeltDown 4 ปีที่แล้ว

    I can tell you've must've been a great teacher for you're all shades of funny AND knowledgeable. You're fun and easy to follow.

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      Wow, thank you, PM. I find that a little humor really helps maintain audience interest.

  • @ClarenceHW
    @ClarenceHW 5 ปีที่แล้ว

    Warm & sweet, great sounding amp.

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      That's a good description. Thanks, Clarence.

  • @49VinCom
    @49VinCom 11 หลายเดือนก่อน

    Thanks for the tour!

    • @UncleDoug
      @UncleDoug  8 หลายเดือนก่อน

      Thanks for joining us, 49 :)

  • @dondesnoo1771
    @dondesnoo1771 5 ปีที่แล้ว

    Saw the amp you made in another video I'm impressed by your impeccable work .

    • @UncleDoug
      @UncleDoug  5 ปีที่แล้ว

      Thanks, Don.

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว +2

    Thank you. It's one of my all-time favorite amps in the world. I'm glad that others can appreciate it too.

  • @ross3818
    @ross3818 2 ปีที่แล้ว

    Those knots will definitely raise the cabinet's resin-ance!

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว

      Good one, Ross. Very turpentinaceous ;)

    • @ross3818
      @ross3818 2 ปีที่แล้ว

      @@UncleDougI verneered off in-terpentine knotty problems which you ply your audience with.

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว

      I am investing heavily in some Tonewood Trees......only 50 more years and they'll be ready to harvest.

    • @ross3818
      @ross3818 2 ปีที่แล้ว

      @@UncleDoug Live Long and Prosper!

    • @UncleDoug
      @UncleDoug  2 ปีที่แล้ว

      @@ross3818 Is that "prosper" or Poplar.....as in tree. ??

  • @chakathewolf
    @chakathewolf 9 ปีที่แล้ว

    Thank you for taking this apart and showing us the insides. If I had an amp that was a year older than me, and one of my favorites, I don't think love nor money could make me loosen the screws.

    • @UncleDoug
      @UncleDoug  9 ปีที่แล้ว

      +Chaka Wolf You're welcome, CW. It is a little risky to take an old one like this apart, but I wanted to check some components and clean up the interior.

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว +1

    No problem, Philo. I really appreciate your interest and inquiry. Virtually all tube amps require a transformer between the amp and speaker, to convert the high-voltage, low-current signal in the amp into a low-voltage, high-current signal that can drive the speaker. In most amps, the transformer is located within the amp chassis, out of sight; but in older amps (like this one) the transformer is generally not in the chassis, but attached to (or installed beside) the speaker.

    • @bobbyowen8716
      @bobbyowen8716 6 ปีที่แล้ว

      Yes, on my old Valco the B+ leaves the chassis after passing over one filter. 450 volts to the field coil.

  • @thespiritof76..
    @thespiritof76.. 4 ปีที่แล้ว

    Amen thank you lawd for your sermon on pulling old caps... tell it tell if

    • @UncleDoug
      @UncleDoug  4 ปีที่แล้ว

      Thanks, 76 :)

  • @amoruzz
    @amoruzz 3 ปีที่แล้ว

    Another cool amplifier, congratulations.
    I've seen those speakers before, but they are usually trashed/damaged.
    Those are in really good condition and triple set up!
    Very unique. I'm curious how they came up with the name for it?
    You always play great chords to match the era of those 50's amplifiers.
    Sounds great, cheers!

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว

      Thanks so much, Amo :)

  • @warrentrucks09
    @warrentrucks09 9 ปีที่แล้ว

    That is a good sounding little amp. The tremolo is one of the best I've ever heard. No joke, I have several tremolo pedals and they dont sound as good. Just amazing little amps really. Thanks so much for sharing with us...:-)

    • @UncleDoug
      @UncleDoug  9 ปีที่แล้ว +1

      +bubba stephens You're welcome, Bubba. You're right about the Aztec tremolo.....it is (IMHO) one of the very best I have ever heard. Thanks so much for your kind words :)

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว

    I agree, BC, which is why I rarely trust old, tattered handles, preferring instead to carry old amps by holding them from underneath with one hand (and the other holding a seemingly good handle) or both hands (if the handle is suspect, as this one is).

    • @bobbyowen8716
      @bobbyowen8716 6 ปีที่แล้ว

      The old valco I'm rebuilding suffered that fate. The plywood top came delaminated and when picked up by the handle the whole top came off. This let the amp fall. The next time it was plugged in the power cord melted. Turns out that the deathcap shifted position and shorted against a ground lug on the tube socket. Now I'm a firm believer in T nuts for the handle.

  • @jonnybeck6723
    @jonnybeck6723 6 ปีที่แล้ว

    Remarkably knotty (naughty?) cabinet, there Uncle Doug... chosen for its
    superior hardness (?) What with the abundance of particle board these daze I find
    meself pining for the natural approach...

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      Knots add even-order harmonics, Jonny ;);)

  • @mickeymantool8188
    @mickeymantool8188 11 หลายเดือนก่อน

    I owned one of these amps. I fell on hard times and had to sell it. I really wish I hadnt😢

    • @UncleDoug
      @UncleDoug  11 หลายเดือนก่อน +1

      I sold mine too, Mickey, and like you, I regret it.

  • @thorpejsf
    @thorpejsf 9 ปีที่แล้ว

    I recently came into possession of some big-bottle 6L6G tubes, and now I think I know what I'd like to build with them.

    • @UncleDoug
      @UncleDoug  9 ปีที่แล้ว

      +Jason Thorpe The Aztec is one of my all-time favorites, Jason. Just remember that the G's are biased much cooler than the GC's. Good luck :)

    • @thorpejsf
      @thorpejsf 9 ปีที่แล้ว

      +Uncle Doug Do you have a good schematic for this amp? I've found a hand-drawn one, but it is a little unclear in a few spots (missing values for the "bass" input resistors, no type type specified for the tremolo oscillator, connection a bit unclear for the output of the tremolo oscillator... to the 6L6 cathodes?)

    • @UncleDoug
      @UncleDoug  9 ปีที่แล้ว

      I have seen the hand-drawn schematic you are referring to, and, sad to say, it's the only one available......and it's neither accurate nor complete. I too looked all over and was unable to find anything by National, Supro, or Gretsch that was even close. Maybe you'd be better off building a Supro Thunderbolt.....they're extremely popular.

    • @thorpejsf
      @thorpejsf 9 ปีที่แล้ว +1

      +Uncle Doug Ha! And extremely simple!

  • @luthravin4774
    @luthravin4774 6 ปีที่แล้ว

    That was an awesome experience Uncle Doug.. I actually thought I was in a time capsule.. your demos new or older are really interesting.. they maybe old in time of posting .. but I’m watching and learning for the first time!! Granted your soloing on this one as Jack and Rusty are on a Search and Locate mission!!👀👀. Thanks

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      You're welcome, Luth. Thanks !!!

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว

    In the Princeton, the 12AX7 oscillator output is sent to the grids of the 6V6 output tubes varying their bias, as you said. But in the Aztec, the cathode output of the oscillating 6SQ7 is sent to the cathode of the 5879 pre-amp tube, varying its bias. The principle is the same, but the two amps apply their oscillating signal to opposite ends of the circuit. You would think the results would be quite different, but they are both similarly wonderful tremolo's.

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว +1

    I'm glad you like it, Henry. They don't build them like they used to.

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว +2

    After some more thought, it came to me that this shielding is against radio interference (from above). Back in the 1950's and 60's, powerful AM stations used to cause all sorts of RF interference with electronic devices. I've also seen amps (i.e. Fenders) with either screen, foil, or sheet metal above the top-mounted chassis for the same purpose.

    • @abubakr6939
      @abubakr6939 4 ปีที่แล้ว

      Uncle Doug even nowadays we can get this happening.

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว

    PK, it's rarely just a tube that causes a tremolo malfunction. More commonly there is a problem with the three capacitors that induce the oscillation. My Aztec had this problem when I got it, and the caps were at fault. The tube that oscillates in the Aztec is the 6SQ7, so you can test it and see, but it's a long shot. The best place for replacement tubes is Antique Electronic Supply (also called Tubes and More) in Tempe, AZ.

  • @Bleats_Sinodai
    @Bleats_Sinodai 11 ปีที่แล้ว

    I only trust handles made of pure leather, or the rubber/metal Fender-style, since those can survive a lot of stress through time.
    My first SS combo has the Fender-style handle, and I'm thinking of re-using the whole thing (minus the metal chassis) for a tube amp. I had an idea for the phase inverter that I wanna try out.

  • @dwightbehm2886
    @dwightbehm2886 7 หลายเดือนก่อน

    That is an interesting amp. What is the speaker impedance and are they wired in series or parallel? It sounded wonderful with different tone equalitys for each input.

    • @UncleDoug
      @UncleDoug  7 หลายเดือนก่อน

      I have no recollection, Dwight. The amp is long gone.

  • @jonnybeck6723
    @jonnybeck6723 6 ปีที่แล้ว

    Is there a way to reduce current draw in a modern solid state rectifier so as to reduce the load on the power transmixer (transformer) ?
    As I learn more, I see what you dig about this puppy...
    It reminds me of an old double chassis Supro.
    cheers

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      You can install thermistor(s) in the primary circuit and/or use a GZ34 rectifier tube, with very slow start-up. The National may be the same circuit as the Supro, Jonny......they are both made by Valco.

  • @pkgannon
    @pkgannon 11 ปีที่แล้ว

    Thanks Doug for the info!

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว

    Thanks, Chris, and you are exactly right about the 5V4.....IMHO the best rectifier in the universe for these old amps. It has slow warm up (indirectly heated cathode) and only draws 2A of filament current but still produces plenty of DC. Unfortunately, they are relatively rare and expensive compared to 5Y3's and 5U4's.

  • @plateoshrimp9685
    @plateoshrimp9685 3 ปีที่แล้ว

    Hi Uncle Doug! Great video. I’ve tried this amp a couple of times, but the cheese gets stuck between the grille and the speaker baffle. Any advice? Thanks in advance.

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว +1

      Thanks, PoS. It's a design flaw that has plagued this model for years, and is responsible for its nickname, "Old Cheese Grille"......not to be confused with the rapper of the same name.

  • @tehnogramma
    @tehnogramma 7 ปีที่แล้ว

    Well i am the owner of one of these wonderful amps and the sound is incredible.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      You're a lucky man, Tex. They are wonderful amps !!

  • @HMJohnsonGuitar
    @HMJohnsonGuitar 11 ปีที่แล้ว

    Cool!

  • @YeeThirty
    @YeeThirty 6 ปีที่แล้ว

    Just gonna put this out there... BMW used "richey" brand capacitors in thier cars in the 80s. The same can be found on ebay from china

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      Very interesting, YT.

    • @YeeThirty
      @YeeThirty 6 ปีที่แล้ว

      @@UncleDoug indeed... and i just found out they are "made in the usa" aka china and owned by a US company... honestly never woulda thunk it haha makes me less worried about them for sure... however i still wouldnt use them for a customer's amp/radio only my own equiptment cause i can always replace em later lol. P.s. woke up to pt2 of the steam punk video... looking sick especially with those "lamps" ;)

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      I'm glad you liked the bubbling pilot lights, YT.

  • @VegasCyclingFreak
    @VegasCyclingFreak 8 ปีที่แล้ว

    That shield around the input jacks... I wonder if they considered noise from fluorescent lighting to be more of a concern than the preamp below it? Was that type of lighting in wide use yet at the time? Just a thought...

    • @UncleDoug
      @UncleDoug  8 ปีที่แล้ว +1

      I believe it was to shield against radio frequency interference.
      Back in the old days, there were immensely powerful AM radio stations with signals that would interfere with electronic devices. I recall KOMA in Oklahoma City, with a 50,000W signal at 1520 on the AM band back in the 1960's. At night, it could be heard clearly for well over 1000 miles in all directions. After the transition to FM, the interference problem ceased.

    • @bobbyowen8716
      @bobbyowen8716 6 ปีที่แล้ว

      Neon beer signs are quite noisy.

  • @kcrmson
    @kcrmson 9 ปีที่แล้ว

    Free subscriptions plus shipping and handling, of course, right? ;)

    • @UncleDoug
      @UncleDoug  9 ปีที่แล้ว

      +kcrmson Yes, indeed. The handling charges are only a measly $10 per day, however.

  • @abubakr6939
    @abubakr6939 3 ปีที่แล้ว

    Doug do you have the schematic for this one, and also for the even more rare stage star that is similar but 4 speakers?

    • @UncleDoug
      @UncleDoug  3 ปีที่แล้ว

      Accurate schematics for Valco amps are few and far between, Abu. I have found a few online, but they tend to be crudely drawn and inaccurate with respect to the amps I have worked on. I'm sorry, but internet searches are about all you have to rely on. Good luck.

  • @roscocsa
    @roscocsa 7 ปีที่แล้ว

    Pretty sure i should be shopping for a corsage after hearing that trem.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว +1

      Well put, Rosco......it must be prom time somewhere :)

    • @roscocsa
      @roscocsa 7 ปีที่แล้ว

      Indeed it is, no doubt there are under the sea shenanigans going on around the country just now.

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      Watch out for the punch. The aftertaste is either cheap rum.....or urine !!

    • @roscocsa
      @roscocsa 7 ปีที่แล้ว

      Here's hoping for the rum.

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว

    If you complete the project, please post a video and let me know about it. I would love to see it.

  • @Bleats_Sinodai
    @Bleats_Sinodai 11 ปีที่แล้ว

    Will do!

  • @Thermionman
    @Thermionman 11 ปีที่แล้ว

    Wow..what a nice amp, love the three 6X11" speakers! neat how the output transformer is mounted on the wood in the middle. Cool that the preamp and power amp/supply chassis are separate, like some radios....,.ah 5V4 for slower warm up ,I think..Neat the way the cabinet cloth is cut inside to make the curves.I like the 6SJ7 and 6SQ7.Sounds really nice and I love the tremolo.

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว

    I find them in pawn shops and on Craigslist. If they have not been worked on by an incompetent person, most old amps are relatively easy to repair. Features like tremolo and reverb can complicate the repair process, however.

  • @adrinathegreat3095
    @adrinathegreat3095 9 ปีที่แล้ว

    Cool looking amp, I like it's design in having the pre amp stage separate, old amps always seem to sound better, maybe it's just nostalgia I don't know, I've got a 63 Ac30 treble head, very tatty, hoping to find a matching cab in equally distressed condition soon.. lol

  • @philo426
    @philo426 11 ปีที่แล้ว

    I don't know a lot about old tube amps so pardon my ignorance,why do the speakers have a transformer attached to them?The speakers I know just have two wires and that is it!

  • @aaronfidelisrecine
    @aaronfidelisrecine 10 ปีที่แล้ว +2

    Hahaha. We're not looking to block rainfall. Always a riot Uncle Doug.

    • @UncleDoug
      @UncleDoug  10 ปีที่แล้ว

      Thanks, Aaron. Glad you liked it :)

  • @philo426
    @philo426 11 ปีที่แล้ว

    Tell me about the Heathkit amp!

  • @pkgannon
    @pkgannon 11 ปีที่แล้ว

    Hi Doug, follow up question. We found out ours is 1955. And the Tremolo appears not to be working. What tube would control that and is there somewhere to get a replacement?

  • @pkgannon
    @pkgannon 11 ปีที่แล้ว

    Hi Doug. Great video. My good friend happened to luck into one of these. A woman had it stored for 40 years. It's in pristine condition and looks exactly like this one. Although I am not sure if it is from 1956 or earlier as we haven't found a date. What would be an asking price for this amp which appears to be in better condition than even this one you have here?

  • @philo426
    @philo426 11 ปีที่แล้ว

    Thanks for the info!Where do you find all of these cool amps?Plus you have no problem getting them to work.They do seem to be well constructed with quality components!

  • @68MalKontent
    @68MalKontent 11 ปีที่แล้ว

    Very interesting construction, and surprisingly full bodied sound. I was expecting less lows from those oval speakers. I guess the combined membrane area plus a decent power capability do the trick. And despite the speakers not having much of an enclosure volume to work with/in, it doesn't have this hollow sound that big speakers in small boxes tend to have.
    To me a good example of a badly matched speaker and enclosure is your 1940 Sears/Natonal amp, which in itself is a rare and precious collectors' item, but sounds like a speaker mounted on a toilet. Maybe it's the recording, but I definitely didn't like what I heard on that video...

    • @UncleDoug
      @UncleDoug  11 ปีที่แล้ว +1

      Greetings, Stan. A lot of people dislike oval speakers, but the trio of them in the Aztec do indeed have a pleasant, warm tone.
      I understand what you are saying about some amps having a hollow, boxy sound, but I have to say that, in person, the National Dobro doesn't affect me that way. Perhaps you're right about it not being well recorded. Here is another video in which it is recorded more accurately: th-cam.com/video/NQfiw4F1Bv4/w-d-xo.html It is played at 3:17

    • @68MalKontent
      @68MalKontent 11 ปีที่แล้ว

      Uncle Doug
      Yes, in this side-by-side video, with the bass and rhythm background, it doesn't sound as bad, but compared to it's "neighbours" (the National Deluxe and this very Aztec) it sounds cleaner in the upper region, but still less appealing in the low registers. But, well, it's a matter of personal preference :) _De gustibus non est disputandum_...

    • @UncleDoug
      @UncleDoug  11 ปีที่แล้ว +1

      Thanks for listening to the second video. Yes, it definitely has a cleaner, more treble-emphasized tone than its neighbors, and does lack their low frequency response. Perhaps this is partially due to the original 74-year-old electrodynamic speaker. No doubt, the tone could be softened a bit with a capacitor modification, but it's such a "survivor" that I really hate to change much about it. Thanks again for your interest and input, Stan.

  • @AnonymouseZillenial
    @AnonymouseZillenial 10 ปีที่แล้ว

    (: the bantam bass styrofoam speakers the oval speakers reminded me Ive always wanted to blow up a bantam bass speaker one of those weird things on my bucket list lol

    • @UncleDoug
      @UncleDoug  10 ปีที่แล้ว +1

      You're not alone, Wesley. Apparently the (post-CBS of course) Fender Bantam Bass with weird, trapezoidal styrofoam speakers (made by Yamaha) is on many people's "seek and destroy" list. Here is a great article on them: wgs4.com/not-all-speaker-designs-are-good-styrofoam-speaker

  • @UncleDoug
    @UncleDoug  11 ปีที่แล้ว +1

    Thanks, PK, and congratulations to your friend on his acquisition. Aztecs are rather rare and very special. You can determine the date of manufacture by going to the "Valco Pages" dot com and looking up their "Dating Valco Instruments" section. The Vintage Guitar Price Guide states their value at $750 to $900. If it's in pristine condition, I would expect it to bring every bit of $900 to $1000, maybe more from an enthusiastic collector. Good luck !!

  • @jonnybeck6723
    @jonnybeck6723 7 ปีที่แล้ว

    Hey Uncle Doug...
    Greetings and...
    What kind of guitar do you us, or are there many different models, or
    do you prefer to keep this aspect of your vids a mystery for us loyal followers to ponder?

    • @UncleDoug
      @UncleDoug  7 ปีที่แล้ว

      It's a 1980 Matsumoku Vantage V-695 with MMK-45 humbucker pickups that I rescued from a pawn shop and restored. You can see it at the opening of the Shock Hazards video.

  • @Bleats_Sinodai
    @Bleats_Sinodai 11 ปีที่แล้ว

    You should think about getting a piece of leather to replace that handle. It really does not look safe at all.

  • @jonnybeck6723
    @jonnybeck6723 6 ปีที่แล้ว

    I'uz unable to find your email so here'll hafta do...
    Thanx so Very much for your thoughtful (and rapid) replies. They really mean a lot to me.
    ...and a special hello to Casey, Jack & Ollie from Zachery, Tristan and myself
    (that's us about 9 years ago in my avatar) Tristan's taller than me now (younger son) and
    Zach still graciously lets us live in his apartment as long as we observe proper cat etiquette.
    An extra special cheers and Happy Holidays from all of us to all of you.
    'till next time bye fer now

    • @UncleDoug
      @UncleDoug  6 ปีที่แล้ว

      Likewise on all the Christmas wishes, Jonny. We really appreciate your time and interest.

  • @SuperCarver2011
    @SuperCarver2011 9 ปีที่แล้ว +1

    Classic chicken head knobs. "Warms the cockles of yer heart"..haven't heard that
    expression for a long time now..LOL! Electrolytics do 'dry out' over the years, but
    I agree with your philosphy.."if it ain't broke don't fix it...or change it"
    Were the three speakers wired in parallel.
    With the tremelo on, that opening chords sequence sounds a lot like "Earth Angel"? by the Temptations.
    "Earth Angel, Earth Angel..Will you be mine?"