Capacitors More Leaky than the FBI!- National Valco Tremo-Tone 1224 Repair
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- เผยแพร่เมื่อ 28 ส.ค. 2024
- In this video we'll service a very cool 1954 National Tremo-Tone guitar amplifier and talk about why it's so important to go ahead and change ALL caps - electrolytic AND signal coupling caps - in most vintage amplifiers.We'll show how to test for and identify most leaky capacitors in circuit while the amp is on. (Repeat at your own risk!!!) We'll also talk about why I don't usually bother testing replacement caps for outer foil orientation. Grab some popcorn and watch the sparks fly on that one!
Tube Amp Repair Essentials: kit.com/TheGui...
I’m glad to see I’m not the only guy to confirm my repair with a guitar plugged in and amp cranked right from the get go!
What a TONE! Amazing what some of these old amps sound like! Credence Clear Water Revival would be proud of that TONE!
Ed Dana well it's no Kustom ss amp, but CCR might give it a whirl 😅
Great snake-oil-free video! Perfect example of real, down to earth troubleshooting and repair with real proof and practical measurable results. No magic polarities and kryptonite heat shrink tube shields.
snake oil free. a lot gear now with Probably leaky couplings or some that are shorted out dead totally. same with a lot of electrolytic's could use a changing.
That homebrewed tripod is awesome. Lots of people have old lamps kicking around that have a floating arm just like that, so you may well get copied.
This is fantastic! Back in the ampaholic saddle again! By looking at the amp you would never know it had been serviced and brought up to today's standards and safety. The collector now has an amp that can be played without knowing it has been serviced. That amp would be a Hugh asset in a recording studio. Thankz
It belongs in a recording studio. With a tube screamer in front, oh the lead tones you'd get!
They'll be able to tell it has been serviced, but the reaction should be relief, not dismay. "Oh good, angry pixies aren't going to kill me."
Just a friendly note: If your amp has a Schmitt, or Long-Tailed Pair phase inverter stage, that tube will have significant DC voltage on the grids by design.
Here I am again watching more amp repair videos.
Boy,that guy packed that amp perfectly! Couldn’t get any better.
I own a 1951 12 watt Valco National 1212 which I had serviced last fall. It has the twelve inch original Jensen speaker.
It works great and I gig with it (carefully)
I would sell it, but not for less than $1000.
There just aren’t any of these around. 72 years old and still chugging.
That Tele on clean tone... Killer!!! Another nice adventure, Brad... Thanks for the invite....
I totally agree with you about the whole j hook situation. I would add that for a paying customer, the extra time involved just becomes an extra unneeded service charge.
I never thought about checking coupling cap leakage this way but it makes perfect sense.
The shield of a power supply cap can reduce noise by shorting the noise to ground. That's not true of a coupling cap. Noise picked up by the shield of a coupling cap can not be shorted to ground because neither end of the cap is connected to ground. The direction of the coupling cap shouldn't matter because the noise will be shorted to either the previous plate or the following grid, basically the same thing.
Coupling caps can be put in wrong. The foil side goes to the closest point to ground. Check out Carlsons Lab video on the subject.
Maybe it's just me but I like this amp much more with a single coil. Nice video and thanks for the entertainment!
Love your camera mount. What a great way to recycle an old work lamp going!
Thanks for tips on testing leaky caps. Watching you do it and explain it, it makes perfect sense. I'm not still comfortable enough to be poking around a live circuit just yet, however :-) Oh, and nice "vintage" compressor you got there @ 3:49 :-P
I think it sounds good! That is what is most important right! It now has another lifetime of use ahead of it! The best form of recyling is keeping devices working instead of tossing them out! The second best form of recycling is giving new life to a device!
God this amp's raunchy tone really has character. I wonder how much the mismatched coupling caps in front of the output tubes contribute to it.
I'd say nothing. This sound I contribute to paraphrase phase inverter being mismatched because of drifting resistors. The coupling caps just differ a bit of bass, basically.
When I was in Medical Equipment Repair School in the USAF one thing they pounded into us was safety and jewelry was forbidden when working around circuits. Just saying.🤔🤔🤔
Watched the video a 2nd time just to hear that sweet intro song. Great video as always!
As always, interesting and impressive. You are the diagnostic wizard.
Loving the new intro style, simple yet so smooth
Awesome Channel #Guitologist !!! Im learning a lot!
Outside foil orientation does help on the first gain stage. Sometimes it doesn’t help at all!
Grounding schemes and proper lead dress are far more important, even then, that doesn’t work every time. Look at the lead dress in this National, looked like a Zabco ™️ brand birds nest and it’s still quiet!
Merry Christmas to you and your wonderful family!
It's amazingly quiet, you're right. That's PTP for ya. Sometimes a well thought out layout makes everything fine, even if it looks like a plate of spaghetti.
depends on the circuit. In modern circuits its doesn't make a difference
I agree with you on cap foil orientation. I have never found an audio amp where it made any noticeable difference myself. ;^) Others seem to vehemently disagree. LOL
Very true and another forgotten one is a grid stopper at the first stage right near the tube socket pin to block RF and parasitics.Very few designs have one
If its designed right the RF should already be blocked anyway
Amplifier packing level-master!
It was a real work of art. I probably won't pack tubes forthe return trip, but yes, on the whole, he really nailed it.
Something about those old amps like Valco. Good vid Brad.
Nice old Valcos are cool,as are Magnatones but man I'd have to sell my car to get one of those ! I don't think the Wife likes to walk so it's going on the wish list ! Great repair and comments!Staying tuned for more.Peace.
Great result beautiful tone .
That dude sounds awesome!
Maybe it’s my speaker, but that tone has a bit more fuzz than I care for. Of course, my main amp is an AC15, so I guess I’m used to a chime-y sound. Cool video, as always. Your videos taught me about red-plating, so I knew what I was seeing when one of the output tubes on my vox broke and caused the other to go hot! New set of JJs and it’s back humming.
first thing I noticed when I switched from old British amps to old U.S amps.
They sound different.
Cant think why?....
Good instructional video, thank you Brad, I like your Martin shirt. I should get one or two.
I had to add something... Damn son! I love to hear you play guitar! 🎸 Thanks Brad!
I have the same rainbow coffee cup from the 80s LOL - love your videos man. Cheers!
Sweet! Getting back down to amp business.
Brad - the title of this one had me giggling for a good five minutes + (still giggling). Thanks for the laugh this morning, God Bless you, your family, your endevours, and of course your health. Have a scotch on me.
Thanks Mike.
Hey Brad, Merry Christmas to you and all. Those speakers look very similar to some old tube radio speakers I have seen in 50's automobile applications. Many were in the center dash position, and took many years of Sun, and humidity. The paper cone would warp and cause pole piece miss-alignment. Rattle, buzz city. I agree on the cap replacements, no need for foil side searching in these types of applications, Radio, ham, tuners, oscillators, high gain, pre-amps, where signals may be lower than noise levels, definitely. As far as the j-hooking, been there, lol, ofc not as many as you, but my trick was to not mess with multi populated terminals, j-hook them. The singles, and some 2 or 3 junction points, I used a solder sucker bulb, some wick maybe, then cut the loop, they will fall out, most times :) All depends on the resto, fanatic or get it safe, working, and sounding good.
I’ve also run into microphonic output tubes that came across sounding like a bad speaker, or more accurately sound like a cabinet rattle. Not saying that in this case, but just adding for those who may not have the experience you do with amps.
That seemed to be the case here. Changing output tubes got rid of that last little bit of noise after changing caps.
The Guitologist I should know better than to comment before getting to the end of the video! Lol
Oh, and fwiw, I’ve built, repaired and restored hundreds of amps myself over the years- and never once made note as to polarity of small signal caps, with one exception- I faced all caps in the same direction (with the labeling up) on the old Marshall turret boards or Fender eyelet boards- for no other reasons than it looked neater, and made things a bit easier for the next guy in the amp.
The reality is that no electronics sold were designed to last more than a decade (the marketing "turn around" period of the time). Nice to see them being restored !
Hey Brad. Happy New Year. I've been enjoying all of your tube amp repair videos but this one is one of my favorites. Extraordinary tone coming out of this little guy and, as I've mentioned before, you're one hell of a player. Keep 'em coming please. Thanks again, JC
Fra-gi-le... must be Italian! I think it says “fragile”
It’s Christmas time, I couldn’t resist.
He had yellow eyes. By God, yellow eyes....
Great job. Diggin' the new camera setup. I feel like I'm sitting there with you lol.
That is one clean, sweet looking amp too.
I've "J-hooked" more often than not. I have a Collins transmitter/receiver and j-hooked every cap, and there were scads of 'em. You can still do this and make it look neat, like you did. And newer caps are almost always smaller and easier to position.
I've reworked a few old Zenith TransOceanics and restuffed those multi-cap cans. It's not easy, but it's worth it, at least to me.
That amp is old as me, I need new caps.
You're overbiased.
I put a warehouse 8" ceramic speaker in my 72 champ, it rocks!
The outer foil does not go to the lowest potential, it goes to whatever has the lowest AC impedance to ground. So for example on an interstage cap the outer foil goes to the plate of the first stage, not the grid of the following stage, because the input impedance tends to be higher than the output impedance of the previous stage.
Not that it makes a difference on this amp.
I have a Supro "Golden Holiday" with a gold anodized aluminum TV-screen shaped grille. It appears to be the same exact amp as this one except for the grille cosmetics.
Great Video. Love that Charvel 750 XL.
Brad, given your talk in the previous video about the personalities of people who engineer or repair or tinker, I wonder if you've listened to the "S-Town" podcast. The subject of that series is a troubled man who restored antique clocks among other things. I thought you might be interested if you haven't already heard it.
Haven't heard that. Got a link? I do know a lot of people use this kind of tinkering as therapy as well. And it's perfectly suited for it. I'd say in people with low self-esteem or social issues, electronics tinkering can provide a refuge and boost in self-worth. Solving a problem that seemed insurmountable is a great feeling.
Brad, I sent an email to you with a link. I hope that's okay, and I hope I used the correct address!
what s impressive mean little amp, sounds classic. Would sound great with a tele.
But knowing the Foil End soothes my OCD !!\m/!!
I think I see you using a Hexacon soldering iron; I have a really big one that gets used when I need to solder directly to a chassis. It really works.
That thing sounds amazing
Nicely Packed
Great video. So much great information.
Btw, what'd you think of that guy's packing job? It sure survived the trip.
It was the most thorough packaging I've seen. It was a tad overkill even, but hey, it worked!
That little amp has a nice sound
Did somebody play banjo as a kid? That is some very interesting right hand work you have going on there. 34:38 I always knew your finger nails were long for that reason. I've heard you play. This is the first time I actually saw you play. Kind of have the Jeff Beck/Claw Banjo thing going on there! Cool. Very unique style.
I would like to share a recent Vaco purchase I made - very similar. Trying to decide what to do with it. 100 % original. The 1959 Rola 12 inch speakers sound really good with these - conical dust cap with point facing out. I have the model, but too lazy to get up right now. The amp I just purchased is a 1958 model and has the 6973 tubes and the two weird speakers. I will be adding a jack to allow use of an extternal speaker. Let me know it you are interested in pictures.
Good looking Charvel.
Hey Brad-There is a new old stock peavey ultra 112 tube combo on ebay right now for 379 dollars plus 42 dollars shipping. I'm telling you because I don't have the money right now and I would like somebody I somewhat know to get it. It won't be there long. Has foot switch and all the candy, made in USA. 60 watts. 3 channel. He took it out of box to make sure it worked. You have to see it to believe it. My dream amp-Oh well-Hope you get it if you want it. good luck.
Uncle Doug has an excellent video on reconing a speaker. I don't know if you've seen it.
I have. And I know I can do it, but the cone kits are expensive. It's almost more economical to just find a used speaker that works.
Isn't reconing an oval speaker an extra layer of difficulty? And you'd have two of them to worry about.
I remember Parts Express offering reconing service, but I have no idea if they still do. Their prices were probably less than replacement in many cases.
That's one massive soldering iron you've got there. It reminds me of the ones we used to use to solder tin in metal shop ;-)
That's Big Bertha. She's a monstrous lady who enjoys Wagner and Viking style headgear.
I build a lot of pedals, just for the fun of it, --- but I'll tell you, I could never get anything done with a 15 watt/30 watt/ 40 Watt radio shack, or Weller, sodering iron. I went to a no-name brand 60 watt and that was the spot. I can solder anything! in 2 seconds flat, try that with your tiny low watt soldering iron...... Especially on a tube amp.
My favorite soldering iron is a butane Weller, it is portable, takes like 10 seconds to warm up, and it will solder things in 1/2 second flat. If you are in close quarters, you have to be careful, it might melt anything next to it ....
Sorry, didn't mean to sound combative, I was just expressing my joy at finally learning how to solder...
Put simply..". It's a BEAST!!!
Speakers ended up being ok? Love your stuff. Thanks👍
What a fucking nasty tone, Brad! Great repair - good call on the shotgun caps!
Thats a sweet oldy... good sound.
It depends how speakers are gone bad. But believe it or not you can repair most cones with just some paper towel and wood glue with some water.
B Breeuwer i use toilet paper and nail polish
+Richard L
As would I. I wouldn't try to patch a large section of the surround that way, but for a tear with no pieces missing, clear nail polish and tissue paper absolutely work. The nice tissue paper you get in gift bags at Xmas works rather well. I was gifted a pair of 12" hi-fi speakers from 1960 or so, and both woofer cones were torn. I patched them up and ran them hard for the next five or six years. I don't know where they are now, but they may still be functioning.
@@Chemist1076 Ooh ,ouch that would sting like hell!
National Valco.. even those oval speakers crank it out..!! Nice job..!!
As per RCA from back in the day J hooking is a acceptable practice and they encouraged that including the U.S. military.
And another GREAT vid... thanx Brad.
Also great 'woman tone' (and great playing all around)
cheers
Great packaging for sure.
+The Guitologist No question, time to drain the swamp! You know who will be proud...
I like old tube junk and see an interesting piece of old military gear in the opening section. Even when it is not an amp that old gear has many useable parts, when it can be bought cheaply. LOL
Nice!
To really support it they would need something empirical like using a transducer and spectrum analyzer to record the out spectrum. I guess you could also use an attenuator and run it into a cheap scope with FFT built into the match functions so get a crude image of output with out the speakers? Not a fan of J-Hooking but I can understand why you do it. I do not work on things as old as these and do a lot of rf work.
Out of curiosity, were those tubes still red-plating after the recap?
The Capacitors Polarity Outer Foil and Inner Foil is to reduce RF, HUM, LED Lights, interferences it helps reduce signal to noise ratio I think, correct me if I'm wrong
That is correct, but you really need proximity to induce noise into a capacitor.
@@TheGuitologist What do you mean by "proximity" to induce noise into a capacitor? Because most guitar amplifiers use "non shielded wire" so it would be radiating a bunch of different noises which should be in "proximity" of a capacitor.
@@waynegram8907 Hi Wayne! I think you meant - "...increase the signal to noise ratio..." Brad probly meant wires or components that are real close together, even touching.
Could you tell us more about the "Death Cap"? Why it was put in? Why you remove it? Thanks!
best intro ever,,, wee tune was a bit pants but yeah it worked.. :P
I need to get my old National Deluxe to you. It would be wrong to have anyone else service it.
+lp59pete bradlinzy at gmail ...send it in.
ah u made mr. carlson cry with ur "screw tha foil" hahaha have a great day brad :-)
If you put an AC wire right up next to a cap with reversed foils, yes, it matters, otherwise, no.
oh i listened to u explain it in the video. i just figured u watched mr.carlsons lab like shango n was just fuckin with ya brad. figured ya needed a laugh after yesterday. wasnt serious.
Oh I know. All good. :)
That Mr. Carlson video was VERY interesting. I enjoyed it very much, and I do think in some applications it probably makes a difference. Great channels, Mr. Carlson and Shango066. Shango is one of my favs.
All that leaking means one thing-they've gone rogue! Amp sounds nice but I can't help think caps constructed more period correct would have been nicer in that cool vintage amp.
What came of the speaker situation?
I was surprised to see the Charvel going to this amp!
But Boy ohh boy, did that tele sound right!
Passive pickups in the Charvel. Like a hot PAF style. Tele was better. Hums too dark for my taste in this one. The speakers cleared up after replacing all caps and output tubes. There was a bit of cabinet rattle here and there, so I'll tighten things up a bit more before shipping back, but they seem ok, thankfully!
Speaking on having to go back to a tech several times, I had a highly rated tech basically jerk me around on a Carvin XV212 for three months over a ground issue. He would scope it and say it wasn't red plating and also grounding out, I would bring the amp home and it would buzz like a chainsaw intermittently. The guy would take it back and state it was fine ect.... this took place several times. Finally he checked after all this the screen resistors and film resistors. Took him another month according to him to order the screen grid and cathode resistors. That seamed to fix it but the amp still eats V1 12Ax7s ever so often. He also went ahead and modded it to be adjustable and even hit the circuit board with his iron. So I have a black spot on a non replaceable board. He seamed to get really upset because I wouldn't let him turret board the whole amp and "blackface it"....
+Marco Muiretta that's a cool amp. Shame about the issues.
Its virtually impossible to find a non gear biased tech In South Orange County California. Or one who plays customer favorites ect.... I have had a Laney AOR30 in a shop now for 3 weeks simply waiting for the tech to pick it up for a quote. Still no word hasn't returned the phone call, I know have to drive 3 towns over and basically pick up my yet non repaired amp. This again from a so called reputable tech. I am at the point of simply saying whatever when my gear goes down and ether storing it or well, throwing it out.
I contacted one person who tried to argue with me that Laney wasn't any good and also tried to ignore over the phone the fact the Mouser and MAJ Electronics still handle those parts. Got sort of pissy with me and said I had to call him back in a month maybe we will get around to allowing me to bring the amp by.
And you didn't bury a .357 slug in his knee?
Primo video, thanks.I appreciate your straight, no-nonsense repairs and suggestions. Do you have vid a devoted to/showing your test equip. setup, techniques? Some tube/amp guys have piles of vintage test stuff, etc. What do you think?
Is it the stomp switch?
HA! The dreaded 1950s Valco true bypass switch problem! :D
Great Video Brad ,keep at it \m/
The tone from that amp sounds like my friend Warren Haynes. Cool amp (now that is)..
I've got a Dukane pa amplifier that has all the original caps, they are labeled Tiny Chief, same deal, all are leaky as can be.
Cool!!! Sounds best with Telly and tremolo in my opinion, nice playing too.
Did you solder those electrolytics right to the chassis? Or the old can cap ground? I didn't see a terminal strip. Guess ill have to rewind and have another look.
As soon as the vid started all I could think the whole time was, "he needs to replace those caps"
Great video bro. Not sure if I have already asked but what cleaner and polish is best for both acoustic and electric, mine really need doing. ATB
Brad, What's your set-up for test equipment and soldering station? I saw that nice Fluke meter, but do you have a old HP oscilloscope and Frequency generator and a temp controllex Weller soldering iron?
Did you make sure the oxygen was fully sucked out of all the wiring and you had the correct orientation for efficient current flow.
Lol, I also noticed he did not have the amp facing North and South when installing those caps... shame shame... hehe :P
Thanks, another great vid and advice. Lovely tone you got, what’s the neck pickup in your tele? Looks like a gold foil.
"Have you High Voltage Rock and roll" then you need new capacitors!!
I have an old ampeg. Just replaced the electrolytics but do i need to teplace the canister cap???
Brad, I don't understand the .05uf capacitor. I understand it's blocking high DC voltage but is it filtering anything? Hasn't the signal already gone through the .02 cap after the first stage? Thanks, Rick.
+Rick Chavez high voltage D.C. And low voltage signal AC exist in the same wire. The cap disallows the DC to cross, but allows AC at a certain frequency cutoff to cross determined by the cap value.
So the speakers were still okay in the end.
Do you have a schematic for this amp? I just went over mine and changed those RCW(?) and Mallory caps, I left the ceramic discs in place, except for the death cap which I removed. I used schematic Supro S6424 and to some extent I had a look at Supro 1694...
WOW that Valco sounds awsome ill keep my ieye out for one or a victor how much would you suggest a cheap one is ?
Brad, are you still taking in amps for service? I have a 65 VibroChamp that I wouldn't mind you doing a service on.
Brad, where do you purchase your capacitors? I need to replace the filter canister in a Kalamazoo Model 1 and I can't find individual replacements cheap.
Antique electronic supply