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previous: Dai Hirokawa Re: Same noise, plus hum and oscillations - HELP! -- 11/6/2003 3:28 AM View Thread

Oscillations

11/9/2003 6:32 PM
Albert Kreuzer
Oscillations
Thanks Dai,  
 
I checked all grounds, everything ok. Still oscillating. Changed tubes again, appeared that the culprit was a microphonic tube. In the Prosonic gain channel the systems of each tube are in phase (V1a - V2a - V1b - V2b), so I'll blame Mr.B.Z. on that...  
I also resoldered the power supply board, discovered a bad solder joint from R204 to C205 (the last filter cap). Cleaned and retensioned the tube sockets, lots of resin on the back of V2.  
So at the moment the amp seems ok - no strange noises on the bench. Back to real life testing...  
 
Regards  
Albert (hoping for the best)