Hum in Aleph J

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My Aleph J is balanced (XLR). From XLR I have conected plus and minus to RCA. I use jumpers in the XLR connectors between ground an and minus.

When nothing is connected on input I get hum with jumpers.
Without jumpers it's quiet.

When I connect preamp/source its also hum with jumpers inside. But the strange here is that its becomes quiet if I only remove one jumper.

Can someone help me?

Is it necessary to use jumpers when I use rca connections. If I remove jumpers and only use plus and minus it will become quiet. I also think minus and ground will be connected in the preamp side. with jumpers it will be connected at the Alpeh side two, but is it necessary.
 
Hi, I have connected ground and plus to rca

The blue wires is ground wire for experimentation.

If I use the blue wire for ground instead of ground to the cards on each side it's less hum. You can see a thermistor between chassis ground and power connection ground. The best solution is If I remove ground to each cards on the sides and connect one of the blue wire to chassisground and the other one to powersuply ground. Then it will be quit in one chanal and a litle bit hum in the other one.
 

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Hi,
It's two power boards, One for 24v plus and one for 24V minus.

I'ts ground jumpers between the boards. My idea is to remove these ground jumpers and ground each of the board to chassis ground, one directly and the other one with a CL60 thermistor. Then I will connect ground from the left power board to the left signal board and opposite with the right one. Is it possible to do like this? Then I will break the ground between left and right.
 
I'm still working with the ground in Aleph J to keep it quiet. With XLR it's completely quiet, but with RCA it's noisy.

If I connect as shown in the picture, it will also be quiet when using RCA. I then connect ground from one XLR to chassis ground and from the other XLR to ground in the power supply. It's a CL60 thermistor between these ground points.

Are there any disadvantages to grounding this way?
 

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