dual primary//dual secondary toroid

[larryg]

Good day! I have two boxes for my project; the first is for the amps, volume control, in/out, both channels.
The second is for the psu/bridge rectifiers ( some suggest placing
the bridges in amp box?) Will be using xlr's to connect. (NOW?)
For the grounding between the boxs. Any suggestions for this?
larryg

[AndrewT]

Hi,
the first box containing the transformer is mains powered. It must have a safety earth.

The second box is not mains powered. Can you guarantee that your construction will never introduce the risk of mains appearing on/in the second box? If yes then you do not need a safety earth. If you are in any doubt then be safe put in a safety earth. Do not connect any of the safety earths to audio ground.

The wires coming from the PSU box to the Amplifier box do not contain any grounds. I can hear you asking "has this guy gone crackers".

The PSU wires are +ve supply, 0volt supply and -ve supply. You can call the 0volt supply the PSU common if you prefer. BUT IT IS NOT a ground.

If you can get your head to think in this direction you are less likely to make a grounding error that will afflict your amp with hum.

[larryg]

Hi AndrewT. A very 'good' answer for me, 'Your' knowledge and of
others, helps me a great deal; and many others, past & present,
I'm sure would agree. Thank You, larryg