multi-channel hum, one transf, multiple PS

[harvardian]

Hi,

I know this has been discussed ad nauseam, but......

Here is my wiring scenario:

115AC x2 -> 36VAC X2 -> 4 position terminal block

From the terminal block, I run 4 wires (2 x 36VAC) to each of four power supplies(BR/caps). The "gnd"s are commoned on each PS, not at the terminal block. There is only one BR to get the split rails.

SafetyGround->Chassis and transformer ES - not connected to anything else yet...

I get non-variable 60Hz hum with inputs shorted. Not a huge amount, but enough.

1) Should I connect the 2 "gnd"s at the terminal block before they run to each PS

2) Where should I put the disconnecting network to the ChassisGnd? From each PS? At the terminal block? Do I need one for each PS?

Thanks in advance...

Dale

[AndrewT]

Hi,
Bob Cordell has just posted a grounding scheme which should need only one disconnecting network. Power supplies.