Thanks so much, Mark. I would consider doing this, but Netflix has offered me a lot of money to limit my video production so they can stay in business :)

@@UncleDoug Sell out....you're the man Doug, and Rusty of course.

@@donaldlogan3626 Thanks so much, Donald.

@@UncleDoug Personally ... I think you're all wired up ... heh-heh.

@@Tonetwisters My wife would agree, TT.

You're welcome, Stony. Amen :)

You're welcome, Mega. Every once in a while we just like to have some fun, and these ridiculous filter caps were a good excuse to do so. We're glad you enjoy the videos :)

You're welcome, DR :)

Thanks, Dennis :)

You're welcome, Brian. Sometimes the simpler things are the best :)

You're welcome, RW. It sounds like a great amp that has found an appreciative home. I like the fact that you are keeping it original, down to the microphone connectors. Keep up the good work.....and best of luck with all your projects.

You're welcome, KD. Best of luck with your projects.

You're welcome, Nf. That is our mission in life :)

You're welcome, Lep :)

Glad you enjoyed it, Richard.

Pretty Kinky, Hijme ;)

You're welcome, ATL. As I said, it isn't rocket science, but it was SO BAD that I thought you all would get a kick out of it :)

We will, Cass. You're welcome. It's always good to hear from you :)

Glad you liked it, Chris.

You're welcome, Brogh. Let's hope that neither of us ever hears that sound again :) Rusty and Jack say "Hi".

hehe :) I really hope we all do !! Looking forward to the next video !!

You're welcome, Tom. We're really glad that you found our channel. The mechanical tremolo requires a lot of lathework and machining. Have you seen the Ricktone tremolo videos? It's purely electronic and might suit your needs better.

Ah that is actually exactly what I meant! Confused as I was watching your comparison video of the two as I was typing. Cheers and take care

Good luck with your project, Tom.

The patient did respond well to treatment :)

Thanks, T1. I repaired several Philco Predicta TV's many years ago, but have since hidden/declined whenever anyone asked about TV repair. It is true that some caps were doomed to fail shortly after manufacture, while others seem to last forever.

Thanks for your helpful input, Robert.

Glad to help, John. Best of luck with your repairs.

Thanks, SS. Like death and taxes, Rusty always comes through in the end :)

You're welcome, Wyatt. I agree that practical, hand-on training is way better than boring lectures and theory. Thanks for watching and commenting :)

Because school won`t teach you anything you need in real life after the first 3-5 years ;)

Good point, AK. Thanks for spotting it :)

This is definitely the worst one I've seen in a long, long while. A dead shorted cap will usually blow a fuse or fully illuminate a current limiter bulb, but the partially shorted ones will blast you with that dreaded 120Hz tone. I wanted all the beginners to hear that sound, so they will be able to recognize it quickly and know what it indicates. Rusty is still sneezing after smelling that wretched cap.

Thanks, Paul :)

I understand the economics of ESR vs simply buying caps, Colin, but in the long run....especially if you do this a lot.....it will pay off (I think :) Congratulations on your successful Tremotone and Champ projects. It's great to hear that the videos are helpful.

Thanks, Adrien. You're right about it being simpler to go straight to trusty Rusty.....but his contract requires that I at least try some other methods first, so as not to unfairly interrupt his nap time :)

Thanks, Bart. His diagnostic skills are truly impressive :)

This can cap was unusually tall, at least 6". In the future, I will be on alert for the tall ones :)

We agree, TM, and yes, as discussed in many of our videos, all filter caps are discharged prior to any work on the chassis, especially when taking ESR measurements.

We will, Cory :)

Yes, they are :)

Thanks, OG, and welcome to our channel. We hope you find lots of good videos to watch :)

Thanks Doug.

You're welcome, OG :)

You're welcome, Whaler. Thanks !!!

You're welcome, Strat. After a successful sniff job like this, I always treat Rusty to a treat or two. I'll tell him that one of them came from you :)

Thanks, T73 :)

Thanks, Fino :)

No pun intended I hope :) You're welcome, William.

You're welcome, AT :)

You're welcome, Shaun. Their contracts stipulate occasional individual starring appearances. Jack's turn is coming up.

Wow, that would be a bad combination....an explosion that involves a newly purchased part, and it all happens in the dark :(

Solder in backwards ?

Keep looking, Andy, and I'll bet you find even more unseen videos :)

Thanks, JT. Glad you enjoyed it.

Thanks ,Mike :)

Thanks, Ryan :)

Thanks, Phil

Thanks! You too!

Greetings, Mitch. Time to order some new filter caps :)

@@UncleDoug I got some coming cross your fingers I got the problem nailed down thanks again for the knowledge you share with your KZfaq following

Thanks, WTD. Best of luck with your studies and eventual repair :)

Hello Uncle Doug and and company! I'm happy to report that I simply had to replace a couple of pre-amp tubes to solve my problem after determining that it was merely 60hz hum that needed to be remedied. I think after a full re-tube and a tuning of the bias will make my Carvin MTS combo the amp it can be which should be ultra low noise, good clean channel with plenty of nice tube warmth...just gonna start with a simple matched set of EL34s, maybe try a low noise 12ax7 in V1 and regular JJ's in v2-5. Think that will make the mild,but present 60hz hum altogether disappear. Also Uncle Doug, I'd love for you to see this UNCLE Alberts Del Ray--very neat amp and would love to show ya--just go to Craigslist Indianapolis and search musical instruments and enter tube amps...won't be long before you find this intriquing and gorgeous piece of masterwork. It is really really neat! Peace out Dawg(as they said in the 'hood before it became trite.)

Wow, thanks so much, Randy :)

You're welcome, Stuart. Yes, there must be a balance between originality and reliability. Thanks for your input.

I do new builds with carbon comp resistors. There is nothing wrong with them and when chosen for select places like plate loads their high voltage coefficients will add some nice nonlinear distortion to the signal. This is of course wanted in guitar amps so be careful when replacing CC resistors, you may just make the amp too sterile by switching to film resistors. The larger the signal swing across the resistor the more harmonic distortion will be added. To those that say they are "noisy", ones that have failed can sound like bacon frying in a pan but high quality CC resistors will not make your amp noisy. The last high gain amp I made had an output noise level of

I always return the old, removed parts to the owners, 76. I'll see if I can amass some old caps for you.

Uncle Doug would be awesome if you did. I’m sure I could round you up something that could help with a video... I got an ex wife whose as annoying as a Sub tweeter, wish somebody would tune her up.. lol thanks uncle Doug, great video as always

Thanks, JC :)

Thanks, Ian. You will have them :)

Thanks, Otter. It could happen....I just need to do some research and figure out a way to explain it clearly.

+Uncle Doug awesome, thank you

You're welcome :)

Then you're in good company, Jeffry. We all love them :)

You're welcome, Jim. Congratulations on the successful completion of your project :)

Thanks, Delroy :)

I spend about 4 hours a day responding to questions and comments, Tim.

Thanks so much, Joey. Glad you enjoyed the video :)

Thanks for your input, SD.

Rusty thanks you for acknowledging his great talent :)

Long distance radio repair is simply a guessing game, Jorge. A variac will not protect the components in your circuit. For protection, you need a current limiter (see my video). You will have to test the primary input and all the secondary output windings of the power transformer with an ohmmeter (for continuity). If it fried, then you'll have to track down and install an suitable replacement. Good luck.

What model? There was one or two Zeniths around that era that used a pair of 6X5Gs for rectifiers. It was an improper design, and they paired them up with a marginal power transformer for the size of the radio, so they were notorious for shorting and burning out the H.V winding. There are two ways to check the transformer, one is by taking resistance measurements, the other is by pulling the tubes out and powering it up. A failed power transformer usually has one or more shorted windings and will get red hot within minutes, which you can also find by measuring the resistances of each winding, particularly the H.V winding between each outside leg and the center tap. It's possible that the sizzling was a tone correction cap across the output transformer primary, that cap has to be a high voltage one or it can fail and short out.

Safety precautions, including how to make your own capacitor-draining tool, are included throughout the videos, 39P. You really need to watch and acquaint yourself with all of them before touching any of the wiring or internal components of a circuit. A couple of quick suggestions: Never be grounded (skin touching concrete, pipes, etc.), and never touch any circuit with both hands (keep one in your pocket).

Uncle Doug Thank you for those tips! Ill watch your older videos! so far the ones ive seen have been really useful.

You're welcome, 39P. Best of luck :)

You're welcome, MP :)

With my small video camera microphone I have to be careful not to overdrive it too much, or the resulting distortion will give a false impression of the amplifiers true tone. The "2" was indeed rather loud :)

Thanks, Allan :)

I agree, EF. Ray and Dave rule :)

It's to prevent any inadvertent contact between the wire leads, Jon, and is done where necessary.

@@UncleDoug Thanks. I wanted to be sure that it wasn't for signal shielding or something more complex.

@@TheJstewart2010 Vinyl and plastic are only for insulation, Jon......neither is effective for shielding.

Actually, his contract calls for a 70/30 split (to his favor), since he is, as he always reminds me, the brains of the organization.

Man, he always comes out ahead. His handsomeness is what does it for him.

.....and his winning smile :)

Uncle Doug Right you are! You guys have a great night! Thank you for the great videos. I am an industrial electrician/maint tech but limited in electronics. With a few good tube amp books and your truly great videos I am gaining more and more knowledge about my beloved tube amps. Thank you very much for sharing your wisdom and knowledge!

You're welcome, Dave. We're glad to hear the videos are helpful. Our best to you and yours.

Thanks, Andrew. After working on enough amps, you can "wing it" in most cases, unless components of incorrect value have been previously installed.

Plpp

Thanks, Jon.

You're welcome, Christopher. Rusty was just a natural-born component sniffer. Even as a pup, he would sniff and bark at faulty transformers and electrolytic caps. Jack, on the other hand, is slowly developing his cat scanning abilities, but he's still young and I'm optimistic about his future in diagnostics. Perhaps your dog would be more interested in circuitry if you started using bacon as shrink-wrap :)

I believe the Hammond AO-44 (or perhaps the AO-39) uses some light bulbs as variable ballast resistors. It's actually a very clever solution, probably developed before varistors appeared on the scene.

Thanks, James :)

No you can't.....and after I wiped all the snot off the amp, it was ready for the customer :)

I did, Jake, and he ended up stealing the entire box of cookies and hiding under the car to eat them all :)

Greetings, SS. Have you checked the output tube bias? It could be that they are biased too hot and are distorting badly when driven at high volume. I have posted several videos on how to measure the tube bias. If you're nervous about trying this yourself, seek help from a professional in your area.

Amen, MR :)

Hopefully the electrolytic caps in it are better than the ones in mine were :)

I never considered that, M. Thanks :)

Obrigado, Luis, e os melhores desejos para você.

You're welcome, Damian, and thanks for recognizing Rusty's astounding talents. Little did I know when I adopted him many, many years ago that he would grow up to be the most famous amp-sniffing & repairing hound in history. Now, I better go feed him or he'll go on strike :)

You really can't fully test capacitors with a multi-meter. Even if the capacitance reading seems appropriate, the capacitor could still be faulty. ESR meters are specific for electrolytic caps and much better at spotting failing ones, but they don't fully charge the cap to operating voltage, which is about the only absolute way to judge them. I have an Anatek Blue ESR meter and use it all the time. It may not be the absolute most-thorough method to sniff out failing electrolytics, but it very practical and effective. You can use an ESR meter to measure all electrolytics in circuit, unless they are in parallel.....which is quite rare.

Thanks for the reply. So I would be able to test electrolytic caps in circuit with a decent ESR meter? I was looking at either the Anatek Blue or the Signstek MESR V2. I was just looking for a way to test electrolytics to see if they need replacing while still in circuit on my vintage amps. De-soldering would not be a big deal, but was wondering if it can be done reliably enough in circuit with either a multimeter, or a decent ESR meter. I'm going to be looking at as many videos as I can to see how testing on caps in amps like mine are done to determine whether or not they need replacing. I see you have a vid on this with the Blue, so I'll be posting there. Like I said, replacing the filters is straight forward enough, and re-biasing the JCM 800 out put tubes looks easy enough, but diagnosing the electrolytics has me baffled right now. I believe my Hiwatts and Sound City amps on the other hand, ( correct me if I'm wrong please..) dont have bias pots and will need to adjust bias through the resistors. Thats for another time. Right now the JCM is the easiest platform to start with. Thanks for the replies Doug!!!

Thanks, Andrew. The PD was 16.5W for metal 6L6's.....which is just about optimum in my book. I think the guitar input was overdriving the octal pre-amp, but the moment I heard the resulting tone, the Kinks came to mind :) Jack is on hiatus for a couple weeks, studying astrophysics at MIT.

You're welcome, CA, and thanks for sharing your interesting experiences with a PE30 amp. They are indeed excellent for guitar use. Best of luck with yours :)

Thanks, Brad :)

Ray and Dave rule, SC :)

By the way, i like the sound of that PA too 👍🔥

There is no telling what harm might have been done by overheating, Kyle. Yes, SS amp power supplies use filter capacitors. You might want to get a qualified tech to look it over.

Uncle Doug thanks for the reply. Around my area work is expensive, and questionable at best. Id be better off just to get a new amp, ill just have to do some more research. Got alot to learn :)

Kyle Olin or learn to read an use a meter and solder. i want to build one but damn still not that much cheaper with the good stuff.

There was one that was under 1K, LRoy......truly awful. I thought you guys might enjoy seeing this in person :)

Thanks for your input, Ben.

Yes, they were, Tock.....and I intend to test them and add them to my vintage parts stash ASAP :) Regardless of their tone capabilities, they really look neat in a circuit.

CIRCLE OF TONE. Stay away from bumblebee caps they are all junk by now.

The electrolyte, when badly overheated, does have a peculiar odor.

The nectar of the gods......virtually no sugar or fat, and tastes great !!!