If it only happens in your system, could it be something upstream? Try shorting plugs on the input and see if there is still popping sound from your speakers. Does the sound increase when you increase the volume from your linestage? If it does, it is not the amp, but something upstream. How efficient are your speakers? If they are very efficient you may hear low level sounds that all those other repair folks would not find to be as loud as you hear it.
Is My Tube Amp Unfixable? Help Needed
Hi All: It's been a while since I have posted, but I am posting now because I need advice from those who may have experienced something similar. I really am in a tough spot with a tube amp that it pains me to say I am tempted to literally throw away or give away. This is a long story, so grab a beer or cup of coffee:
In October 2020, I bought brand new Quicksilver Mono 120s...FANTASTIC sounding amps, btw, and the third pair of Quicksilver monos I've owned (I also own their line stage preamp). Immediately, the left channel amp began emitting static pops and crackly, intermittent noise...low level but loud enough to hear from my listening position 8 ft. away. After painstakingly exhausting every possible source of noise (power tubes, driver tubes, speaker, preamp, interconnects, iPhone, CD player, electrical socket, power cords, etc), I called Quicksilver and was told to send the amp back...could be a bad resistor but now sure. Quicksilver looked it over and determined that it was working perfectly...no noise. I got it back 3 weeks later and...same exact noise. Several months later, I called QS and explained the situation in detail. They said to send it back a second time with the tubes I was using. Again, I shipped it back, and Mike Sanders did a very, very thorough check of the amp. He called me to discuss, and the verdict was the amp was exhibiting no noise and working perfectly. I got it back and yep...the same noise with the same exact tubes Mike had. In addition, UPS had dropped the box so hard in transit that when I received it from QS, 2 of the 3 binding posts has completely sheared off and were rattling in the box.
So now I had a noisy amp the manufacturer could not diagnose and that was unusable. I was not going to send it back to QS a third time ($100 in shipping a pop), but I needed the binding posts repaired. So I drove it an hour to a local tube repair shop that specialized mainly in guitar amps but who told me he could work on it. And yes, you guessed it..."Your amp is working fine. We checked it out top to bottom, and no noise." $160 later for repaired binding posts, this amp is STILL noisy and actually worse than ever. Btw, I have since moved to another state and set the amp up in a completely new place...same noise.
So, I have a $2,000 amp that I cannot use and apparently no one can repair, and I am at my wits end. Btw, the amp is still under warranty, but QS no longer makes the Mono 120s, so they cannot swap it out for a new one. Do I simply just keep shipping this amp to random repair shops only to hear "it's working fine," or do I literally throw it away? Audiogon, I need your advice.