UBC01 for QSXM3

[yiancar]

heaveno
I get a real good hum out of the balanced output of the ubc01 when connected with a qsxm3

here is how my wires are connected.


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[peranders]

Is your ground connected in your balanced wiring?

[yiancar]

Pin 1 of the xlr is connected to the shield of the wire which connects to theground of the ubc01

[peranders]

If you disconnect one channel (the balanced output) does the hum disappear? I suspect that you have a massive ground loop.

[yiancar]

if i disconnect one of the xlrs completely, yes it does
any suggestions of how to rewire my ground?

[peranders]

Try to identify how a ground loop is created.

[yiancar]

By disconnecting one by one the grounds?

[peranders]

Yes. This should be quite visible.

[yiancar]

I have tried all possible round combinations, and virtually no change.

However i released that if i remove the inputs from the qsxm3 and i put jumpers j1 and j3 it is dead silent.

what does this man? is it my turntable?

[peranders]

Your tone arm must be grounded via a separate wire to the QSXM3. Is that the case?

[yiancar]

Yes its done. By the way the right channel has a louder hum than the left

[peranders]

So...

Cartridge connected to the QSXM3 and then via unbalanced to the amp = no hum
Cartridge connected to the QSXM3 and then via balanced to the amp = hum
Shorted inputs of the QSXM3 and then via balanced to the amp = hum

Shorted signal into the UBC01 = no hum?

Is that the case?

[yiancar]

ok tried everything again, i turned my transformer and puff hum disappeared, there is only a slight sinusoidal sound (much higher frequency than 50hz) but its down to the cartridge noise floor. I guess I can consider this normal?
unbalanced or balanced makes no difference, except that in balanced its more notable as all the volumes are louder anyway

with the outputs shorted now i get perfect silence

[peranders]

You mean inputs shorted?