The Amp Garage

I would consider checking the voltage potential across C61 and it's leakage. It would be prudent to replace it with a 600V version. Especially if the bias voltage is going to be even more negative. At this age these amps are subject to severe bias drift and a leaky coupling caps are commonly the cau...

My rule is to always route the 'Line' or black through the fuse, regardless of the switch. A fused neutral still leaves the AC voltage connected to the equipment if the fuse blows. And yes green should always be ground. Make sure to get yourself a solid connection to the chassis with your green wire...

I've found the additional shielding well worth the effort. I pour both top and bottom layers and connect the two with a grid of plate throughs, to lower the impedance between them. Just a note; In case you're not already aware, potentials above 100V require much greater attention to trace separation...