Tube Amp Archive

Its been awhile since people have posted here. I've worked with P-P and SE 6AQ5s and 6005s for over ten years now, several DIY amp designs and builds, and have some Tips to share. My listening experience is with 6005s mostly, GEs. Be advised, in my personal opinion, after 4 plus decades of designin...

I like the way those Red PRP resisters look in a build, sound nice to but havn't got the amp broke in yet. Only had it up to bedroom level . Im going to try the 2 watt kiwames from mouser. $ 0.65 apiece same size as regular 1 watt, nice green color to. Bill I used those kiwames on my express build....

I'd say you're much better off selling tubes, rather than going through the paces trying to have amps created by someone else, that may or may not be tonal bliss. There is more value in selling what you have now, rather than investing in this venture. If you do have as many as you say and they are ...

How does one determine the appropriate value of a choke for a given circuit?
I have come across a few and would like to use them in future builds, but not sure how to work out which to use.

I like that video keppy. It's surprising the differences, clearly audible through YouTube and my smartphone speaker. I would like to know what the other cable was. This discussion is making me want to go out and start buying new cables. Hah. Do you guys find much difference in speaker cables? I've o...

Thanks tilly. Will do

Thanks for sharing that ginger ninja. Very nicely drawn might I add.

Looks like I was wrong. *facepalm* My last diagnosis was declared while playing with c9 disconnected, from the previous test. I'm surprised it actually worked with the circuit broken like that... All be it, less powerful. I reconnected c9, and it was back to itself. :( I replaced c10 and c12, in cas...

Check out the 12au7a, third from left. "YUGOSLAVIA" stamped on top of GE Electronics. What? Notice the flat plates, as apposed to the ladder or ribbed plates of the more common twin triode there. Flat plates indicate it was manufactured on telefunken tooling. The EI company bought telefunkens tooli...

Great find! I'm so jealous!
I've been searching for something like this for a long time. Doesn't seem to be many tube organs in Australia however just solid state Japanese stuff

Hey guys. Had a bit of success with the amp last night. (bias was ok once I changed resistor back to 220k in the bias circuit). I worked on the phase inverter, decided to change a few things at once, seeing as I was in the area. I lowered c13 and 14 to 100nf, lowered r16 and 17 to 100k, and increase...

I never fitted the diodes on the output tubes, read too many bad reports.

And that second jack has just been removed for the time being

Regarding the attenuator, I'm using an air brake, and the swirl/phaser effect is more noticeable with it. But still there with no attenuation. (I think it's more noticeable with the attenuator because it's in a frequency range that's bypassed by the cap in the air brake) I understood glens question...

Hey guys, thanks for all the replies. To answer your questions, no I haven't tried the amp without v2. That will be on the agenda for tonight. Tilly - The signal level in the final scope pic was in the same range as my les Paul, the scope needs calibration (I only got it recently) so it's amplitude ...

I haven't tried the zobel network yet, as I feel that I would rather find the cause than deal with its effects. Today I swapped in another output transformer, replaced the bias caps, tried 6v6's, replaced power power supply filter caps, cooled the pi bias, re flowed every soldier joint in the output...