Tilpo wrote:Thanks for your reply. I tried to match the scheme from your website quite carefully, and I don't really get the difference, but I will take a closer look very soon.
There are some glaring differences -- the website diagram does not tell you to run a wire from the RCA jack ground to the power supply. Instead, it calls for wiring the RCA jack ground to the volume pot and then to the amp boards (I would run separate ground wires for each channel for this purpose). But those appear to be missing in your build.
The electrical tape for isolation is only temporary. I couldn't think of a better way to isolate them from the chassis at the time.
Most RCA jacks should come with isolating washers, but if not, you should drill a somewhat oversized hole on the panel and then mount the jack to the panel using two non-conductive washers (one on each side), taking care to center the jack such that it doesn't touch the edge of the hole. Tighten the mounting nut really well so that the jack won't shift when you connect/disconnect cables.
Is there a way to insulate the AC mains wires such that they would not cause hum/less hum? I really do want to have a power switch on the front panel.
It's hard to shield AC, if that's you mean. The better solution is to run the wires away from the sensitive stuff. It's all about wire routing.
Is there a way to shield the power transformer effectively?
It's hard to do it effectively after the fact
. A shielded transformer is constructed with shielding bands and/or other implements wrapped inside. You can try putting the transformer in a ferrous box (not aluminum) with mu-metal sheets lining inside, but chances are the magnetic field would still leak out. Rotating the transformer around sometimes helps a bit.