Tube Amp Archive

The mixing resistors provide some isolation between the thee signal sources. But mixing resistors will always provide a bit of attenuation. Thanks slucky, now I see there isn't an easy way around it. Yes, each mixer resistor a provides path back to 0V, via the source impedance (eg about 38k for a t...

They mix/combine CH1, CH2, and the reverb signals to a single path that feeds into the PI. Thanks Sluckey, But maybe I should have worded differently, I've been told that B+ is the same as ground as far as AC is concerned, and from what I can see the reverb circuit is adding a pretty low impedance ...

Hi Folks, I'd like to preface this by apologizing quickly for a lot of posts in a short time - don't mean to spam or anything especially as I'm new around here. For those who saw my last post on the grid leak biased tremolo, this is on the same amp. Now I'm thinking this may just be a gap in my know...

Decrease the value of those 82Ks going to the INT pots. Thanks for the reply sluckey, I always enjoy reading what you have to say over on the hoffman forums. I'll give that a shot when the amp is up and running. This amp is actually being rebuilt as it was truly a horror inside when I received it, ...

Hi folks, I've been tracing through an old amp and haven't been able to make full sense of this tremolo design. Appears to be some kind of grid leak biased oscillator, similar to ones I've seen on old 50s - 60's American amps. Only trouble here is the separate depth controls for each channel which s...

Hi folks, first post here. Long time reader. If I've posted this in the wrong place please let me know. Just as a foreword, I have a background in electronics and have somewhat recently gotten into designing/building valve amps. I'm feeling fairly confident in the knowledge I've gained so far, but t...