Update: Tried three sets of 7199 driver tubes. All tested excellent on a sencore tube tester. Original RCA set is gray plate, humm is minimul ie livable. Second set RCA black plate, humm increased over gray plated set. Third set is GE 7199's, right channel scratchy/crackling sound, pulled them immediately. I find this interesting as all tested excellent on the tube tester, this only proves to me that testers do not tell all. I'm new at the power amp tube game but I am quickly getting the idea that tubes must be graded by ear. Your experiences in this area are greatly appreciated, thanks.
Audible low level humm from Vincent st-70
I'm experiencing a low level hum from my speakers when connected to my Will Vincent st-70 that is audible when not playing music. It is constant and does not increase or decrease with volume setting. Replacing the amp with a SS amp eliminates the humm. I have tested all the tubes and replaced the ones that showed weak. All current tubes show strong with two of the Kt77's showing minor grid leakage but still well within the good range. Humm is in both channels. The amp sounds great but I find the humm annoying between discs. Even though my GZ34 rectifier tube tested good could it be the problem?
- ...
- 14 posts total
- 14 posts total