dstarr3
1000+ Head-Fier
It might just be one of the tubes. Maybe one of the pins is corroded and the jiggling in transit is what makes it sound fine for repair folk. A good thorough cleaning of the pins and sockets might be all you need.In the chance that, hopefully, someone might have an idea of what I could try, I'm going to explain my issue and what I have tried in the past months.
My kit had been working perfectly fine for a couple of months, until suddenly it started having a noise issue on the right channel that with time became worse.
-The issue: it's a crackling/static noise that appears exclusively in the right channel, about 10 seconds after I power on my kit. It varies in intensity seemingly randomly, at times it's louder and at times it's quieter. Here's a recording of it. The noise appears with and without a source connected to the amp (simply plugging it into a wall outlet and plugging in headphones is enough). Changing the volume with the potentiometer does not affect it in any way. RCA's being connected or not doesn't matter.
-What I have tried: I extensively chopstick tested to find any weak connection in my solder joints, and reflowed every single joint in the amplifier. I have switched around many tubes that I know worked perfectly. I have replaced the potentiometer. I have replaced the octagonal tube socket with one that makes better contact. I made sure each tube I try has clin pins and a good contact. I have added the reccommended modification with two diodes at the ground tab (it got rid of noises coming from my noisy pc). I have tried different headphones and cables. Different power cords and wall outlets. I have moved to different places of my house and different houses altogether to get rid of possible radio/wifi signals (I even tried placing my amp inside a microwave).
-The most bizzarre part: I have brought my kit to two different repairman places, on two different occasions. In both cases my amp worked flawlessly at their place (in one of the two occasions I have listened to it with my own ears and there was no noise). Upon taking my amp back home, the noise appears again.
That is when, as I said previously, I tried every wall outlet in my house, made sure there was no signal interference and brought my kit at about 4 different places to test. The noise was always there. I have made sure that my houses grounding works fine, and that I wired my transformer for 245V, which is what I read from my outlets.
As of now I am at a complete loss. I can't for the life of me figure out what could be possibly causing this, and why the issue disappears whenever I bring my kit to a professional.
If you have any thoughts or ideas about what I could do, please tell me. I just want to listen to my amp again
Another option is plugging everything into an Uninterruptable Power Supply (UPS) instead of directly into outlets. That should eliminate any possibility of dirty power.