Tube Amp Archive

I'm very interested in these and would buy at least 5 at a time if this is moving forward. Thanks!! email: jonesyATjonesyampsDOTcom...

Have you looked at Hoffmanamps' stout series? They have a 6V6 plexi that is pretty nice! and would work great in a lunchbox type setup.

If you are already re-orienting the sockets, why not do the Soldano heater technique of a bus wire down each side?

What are you using to create those awesome drawings?

for troubleshooting, I removed the tubes starting at the preamps, then PI and found the hum continued even with all of the tubes except the output tube removed. I did the ripple test and found approx. 25v of ripple on the first stage(output transformer). I added the cap that is specified for the fir...

I replaced the hum balance pot with 2 x 100ohm 1W resistors that I verified were closely matched. I used one of those converter plugs to use a 6u8a tube in place of the 7199. I bought two tubes and two converters at the same time and have swapped both to see if that was the issue. I have a 7199 on o...

Yes, I replaced the 100uf bias cap. Polarity is correct. As for the first filter, I cannot see any remnants of a cap being hooked up their. Solder joints are un molested and there's no mounting brackets or marks showing that there ever was one. I did add a cap emulating the schematic but it didn't s...

I'm restoring a 1969 Ampeg B25 and have replaced all of the Electolytics but the amp has a TERRIBLE hum - even worse as I turn up the volume. I replaced the 30 and 40uf caps with 50uf caps thinking that might help a little but no difference. Also, the first 30uf cap that is attached to the leg leadi...

I'm looking for Marshall JCM 800 style chassis with faceplates. I need the 100w version with the "square" power and standby switch but I can't seem to locate them. I can find the 50w version but not the 100w. I'm working on a custom build where a customer wants 2 each 100w and 2 each 50w but they ne...

No clue what else would be needed. Look closely at the pics. Not trying to be difficult but I don't have any experience with HiWatt. Let me know if you want any more pics - and tell me where you want me to photograph. As for price, I'm open for trades or offers. Biggest thing is I want to see this g...

I've built probably 4 amps in a row now that I've wired the output transformer backwards and had the amp do the whole oscillation thing. I understand why this happens (all had NFB) and I quickly reversed the leads on the power tubes to the transformer but is there a simple rule of thumb so I don't k...

Thanks guys! Very helpful!

Yes, I am attaching the common lead to the sleeve but on a Cliffs, that doesn't mean grounded as I'm sure you're getting at... Some will say it is floating, others will get all technical and say there's no such thing as a floating ground. :) I'll just say its not referenced to ground in anyway shape...

Not sure I follow you. I was referring to the secondary common connection of the output transformer, not the primary CT. I don't recall what power supply I had and I don't see the relevance because the current would flow from the CT to the Anodes of the Power Tubes and be coupled onto the secondary ...

Does anybody know why you are supposed to ground the secondary of the output transformer? What is the harm in leaving it ungrounded? I've accidentally left the common lead of the output transformer isolated from ground using cliffs jacks and the amp seemed to work fine. Then I would add a ground and...