The Amp Garage

I may stand corrected: I believe the caps Freidman had issues with were A R S not A E S... just changed out a batch in a Marshall from 2003. We do work for Boutique amps and saw our share of leaking or simply open caps causing all kinds of fun. No idea how or why Marshall would use ARS caps from a d...

At work last month a recapped a Friedman that was no more then 4 years old. It was built with a 2 section can cap from AES and was already swelling up pretty well. Whatever brand filters AES relabeled as theirs seem to suck! I hope it’s not CE! I’ve used many CE cap cans in the last few years with ...

Do a google search for Hayseed Hamfest... Wow, they have really dressed up their site! Catering to the Ham and Hi-Fi crowd, mostly. I use them regularly for Silvertone, Danelectro, Valco, and similar amps using the smaller size. I would rather not open up the chassis holes, especially on older, rar...

Do a google search for Hayseed Hamfest. They custom make quad caps and these smaller 3-section caps as used in Valco, Supro, and Silvertone amps (and likely others).

Due to the high plate voltage (around 700 volts) the screens are at 50% of that, and the bias is low (about 20 ma per tube). The bias is measured at the 3.9 ohm emitter resistor and the Pacair schematics and tech notes explain what you are looking for. Matched tubes is a good idea, and quality tube...

Due to the high plate voltage (around 700 volts) the screens are at 50% of that, and the bias is low (about 20 ma per tube). The bias is measured at the 3.9 ohm emitter resistor and the Pacair schematics and tech notes explain what you are looking for. Matched tubes is a good idea, and quality tubes...

Masco wrote: ↑Fri Nov 10, 2023 2:54 pm Anyone have any experience with Musical Power Supplies iron?? https://www.musicalpowersupplies.com/products/

Musical Power supplies is decent stuff, especially if you are on a budget. Mojo sells Heyboer made iron which is good.

Is he still too cheap to include bias controls? Funny story: I was working in a repair shop (Triple S), and we were an east coast service center for Mesa-Boogie in the 80's. A customer comes in with a fresh set of Mesa tubes (premium, tested, etc) for us to install in his Mark amp. I put them in. T...

Mike Bendinelli at Mesa told me "we rip those out and put in real tubes, as well as the constant current diodes in the cathodes"...Oh, why ? "they sounded like ass"...

Nuff said. With modern LND-150's you can do so much better as far as solid state tube substitutes...

Our shop can fix it, maybe even improve it .

@FUCHSAUDIO: That approach works, all right. Using higher-rated resistors and/or moving the generated heat off to somewhere else can take care of it. This is a simple, expedient way to fix an amp with this problem. My disagreement with the resistor-and-zener approach is that it constitutes penny-pi...

Honestly, it's not the hot resistors (assuming they are used within their ratings), it's how they are implemented. If they are on a crappy, single-sided circuit board, not elevated so they can breathe, they will be a problem. On the Hot-Rods, I usually replace the resistors and the zeners, and raise...

They are aware of this and working to stop this as well as getting the mark back. Time will tell how successful they are.
These guys are slime.

I would add a 1-M cap to the output of the V1b coupling cap to ground.
I would put 10-Meg resistors from the swinger to the nc and no contacts on the relay(s).
I would add a 1uf electrolytic to the relay diode.

that should clean things up...imho of-course.

I recently restored a '66 Vibroverb that had seen water. There was rust under the board when I lifted it, even under the filter caps. There was DC all over the place.... I ended up buying a Hoffman board (which is fiberglass, FR-4 I think), and transferred the important parts over, and replaced out ...