Tube Amp Archive

Measure the volatage at the junction of the PI coupling cap, 220k and 1k5 grid stopper resistor to see if it is the same on both sides. I think it is likely that there is a high voltage leaking into one grid circuit from somewhere. Since you are observing this on two amps, is the problem on the sam...

...I always get a difference of 10 ma between the tubes. Of course I reversed the tubes to be sure ... Bonjour! Just to be clear on the problem, the higher current follows the tube or stays with the socket when you did this? bonjour :wink: When the tubes are supposed to be matched, it stays on the ...

Unless you specifically buy a 'matched pair' of tubes, you cannot assume that any two tubes of the same brand/model/batch are anywhere near matching. If I misread your statement, then I apologize for sounding ... impatient. Such is not my intent. Then there are some other things to consider - you m...

Hi Everybody, This my first thread here. So first, please let me thank you for your help and I apologize in advance for my English. It's not my native language, and believe me, I try to do my best. :oops: Here is my question : I recently built two Vibrolux AA964 and I have the same issue with these ...