The Amp Garage

I've thought for a long time about making an adaptor for putting a 12AX7 or whatever number would work best, and an LND-150 fet to cover the third triode section and be done with it. You might even do it all FET's. You could change the socket to a 9-pin in some models (except most Ampeg's have them ...

I do wonder sometimes if it’s such a great idea to replace old caps when they are obviously in good condition, the rationale is people are looking for the sound and response from the vintage parts and I’m cutting them out and throwing them away. Of course my opinion maybe deeply flawed and if you s...

Maybe manufacturers like FUCHSAUDIO will start retrofitting a suitable MOV across each half-primary as a simpler and more direct way to mitigate such faults. It's not a substantial expense in production, although we never did it in 20+ years. We rarely get amps back with this type of failure. Hate ...

We use F&T and MOD in the shop. MOD's are a great value, most likely imported, but no reliability issues. F&T are top of the line, a little more money, but I think they sound a touch better. We use them in vintage amps always, especially since they are often owned by cork-sniffers. We use in our twe...

We use ceramic sockets for our power and preamp tubes. I usually use them for repairs (chassis permitting) as well. We do both manufacture and repair. More often than not, we find guys with bad speaker wiring or cabinet issues will end up with the 2/3 burn. It's the most common spot (apart from a ra...

You forget the EL84 and 6V6 have a different bias point, so the modulation will be weaker with a tube needing more negative voltage (and more tremolo swing too), to get the same effect. You could raised R-72 to get more output from the chip (clever circuit btw), or toy with the divider into the LND-...

They also need to be mounted right next to each other so that all wire length used is the shortest. Also I consider the leads of semiconductors as part of its built in heat sink and as such contributing to the items wattage rating. For Zener diodes used in tube amps ( especially if near the output ...

bcmatt wrote: ↑Tue May 07, 2024 5:59 pm

FUCHSAUDIO wrote: ↑Tue May 07, 2024 4:31 pm No reason you can't. I would add a 100 ohm series gate resistor on each, and also keep the 10 ohm source resistors on each, the input drain leads can simply tie to the same point.

So, like this?
2Mosfet.jpg

YUP.

No reason you can't. I would add a 100 ohm series gate resistor on each, and also keep the 10 ohm source resistors on each, the input drain leads can simply tie to the same point.

Anyone know anything about this ? : <iframe src="https://www.facebook.com/plugins/post.php?href=https%3A%2F%2Fwww.facebook.com%2FTrainwreckCircuitsAmplifiers%2Fposts%2Fpfbid029g1UF3x1sESLcEegnVKVZSSZhTWcyC8wMPNSSHRGdwByZHHhnbuzLLUJM5VhPxGml&show_text=true&width=500" width="500" height="818" style="b...

Peavey made tons of 5150's with the cathode caps installed in reverse....I can only imagine how many.

xtian wrote: ↑Tue Jan 16, 2024 4:48 pm Be aware of wires running along the chassis--mechanical vibration during play can make them rattle.

Ampeg used contact cement liberally on the old Jersey builds. They used solid core wire dressed down against the chassis, and then a coating of rubber cement to stop movement.

I’ve had great success with the F&T caps. Just be sure to put a dab of silicone between the cap and circuit board to hold them down. In the bigger Fenders with the doghouse cover the foam block won’t contact the smaller F&Ts and the leads can break. I’ve repaired a few. The wire gauge and electro s...

I am very curious about the mojotone caps , didn’t know about them , thanks for sharing that suggestion Andy I've had pretty good experiences with Mojotone electrolytic caps, but my sample size is pretty small; I've used and installed about 5 radial multi-section cans and about another 6 axial elec...

FWIW: I usually unclip the output transformer CT wire from the main board, and use clip leads and a 1-ohm resistor. Same with Blues Juniors. If the bias is where it should be (or close), I don't mess with a trimmer. If we're doing an overhaul (cap job and tweaks etc), I'll add a ten turn pot with a ...