Here's a great suggestion I got:
"Move the blue standby wire to the negative lug of the main filter cap C22 100uFd 450V. I mean TO that lug, even though this will mean a blobby butt-solder joint.
There are many other PCB problems, but when I started trying to work it out I got a headache. Combined with general low-cost "quality", I'd be real tempted to bulldoze the chassis and start over with proper turrets and sockets.
Getting the massive ripple-garbage localized within 1/8" of ground bus, instead of spread-out over two inches in the middle, may help a lot.
If you do not understand exactly what to do, you can smoke the whole amp.'"
What do you guys think?