Amp Internal Wire

Something like that may well have blown your comments out of the water!

Man, I couldn’t believe my eyes when I saw it. Like double take, think, look again, then realize. It had to have been making contact, the leg was tightly up against the through hole/pad - but wow. I took a photo of that too, I should have posted. If I remember correctly, since I was mainly looking at the underside of the board, it was a negative lead - the positive was soldered properly.

If you replace the AC power wiring use a larger gauge .

Also you have 2@  5 x 20 fuses in your IEC connector that are probably glass ,

you should replace them also with ceramics , Bussmann or Littelfuse .  

2 days, 3 evenings of this Mundorf cable in my amp - Every 4B-ST should have this, I'm so glad I did it.. I think I'm going to order another 1M, chop it up into 20cm increments for speaker jumpers. 4B-ST even today isn't a cheap amp, but I now have a high-end sound which far exceeds a 4B-ST.

+1 @rickysnit 

I have a Jolida 502b tube amp. I rewired it with 28 gauge soild core 9n pure silver wire. The difference is night and day after the wire burned in. The amp has a new hifi sound quality.