Tube Amp Needs Help


I'm using a ASL AQ1001(KT88 P-P). Couple of days ago a subtle pop sound was heard on the right channel but nothing really hurts and everything still working fine after that. But now when I try to do biasing the reading just fluctuating and doesn't register a stable reading, When I turn the trimpots they are responding but the digits on the multimeter just keep jumping like 0.450,0.394,0.466,0.501 etc. I switch the tubes around but the problem persists. Can someone help me on this problem? Tks.
I had the exact same amp with more or less the exact same problem. It's just one of the tubes that won't bias, right? I mean, one of the tube sockets irregardless of the tube that is placed in it? Mine had both a faulty bias pot and something else going on, I forget. You are in need of a Jimmy Neutron-type tube geek who can get in there and test the circuitry. This is someone who will understand terms like "plate resistor" and other things that the average non-technical audiophile doesn't fully grok. The good news is, Divergent Tech (distributors of ASL) will probably send you parts in the mail for free if you describe the problem to them. Then you will need to have someone troubleshoot the amp and install them. I got mine fixed up by somebody who is no longer in business locally and it's making me nervous about what happens when my current tube amp (Anthem Amp 1) needs service. Alternativley, enroll in night courses and get a degree in electrical engineering :) Good luck, Jeff
Tks Jeff. Yes and no. I do have the same promblem as yours before. One tube couldn't bias but mine was one of the tube is damaged. What demaged the tube could be as what you said. After changing it the amp works fine but the extreme right(#4)tube that I replaced was the most unstable one(not haunting but reading changed everytime I on the amp, the rest were around 0.470v but this one quite often diff from the rest).
What I'm having now is the bias haunting. All 4 of them. I got someone told me it's either the feedback loop got problem or the tubes are not well. I doubt so is the latter.