Buzz when GPU is loaded

[beefkabob]

It's red to 2 and shield to 1 as built. Lots of hum.

Tried red to 2 and shield to 1+3. My 708p then stopped working. I had to do a factory reset on the monitor.

I tried red to 2 and shield to 3. Same amount of hum as 2 and 1.

I suppose I can try to 2 and 1+3 again. Hopefully it doesn't break the speakers. I never had to do a factory resent before.

 

[antcollinet]

My adapters are wired RCA center to, when looking at the back of the XLR, upper left, and shield to upper right. I think it needs to be shield to 3 or to upper right and 3. Gonna solder.

Does your RCA cable have two conductors plus shield.

An RCA to XLR cable can't do anything at all for noise unless it does. Standard single core plus shiled can't implement any sort of pseudo balanced connection.


Then you need at the RCA end:
Ring connected to shield AND black (cold).
Pin connected to red (hot)

At the XLR end,
Shield connected to pin1/green.
Black/cold connected to pin 3/black
Red/hot connected to pin 2red.

 

[beefkabob]

Does your RCA cable have two conductors plus shield.

An RCA to XLR cable can't do anything at all for noise unless it does. Standard single core plus shiled can't implement any sort of pseudo balanced connection.


Then you need at the RCA end:
Ring connected to shield AND black (cold).
Pin connected to red (hot)

At the XLR end,
Shield connected to pin1/green.
Black/cold connected to pin 3/black
Red/hot connected to pin 2red.

Na. It's a super cheap solution. One conductor and one shield. None of the twisted wires for rejection. I have a bunch of xlr wire from massdrop. I don't know what the quality is. Maybe I'll have to wire these up myself from scratch. To say that I'm bad at soldering is to insult every bad solderer. I'm abysmal. Shameful. Terrible.

 

[antcollinet]

One conductor and one shield.

Then it doesn't matter how you wire it - it will do nothing for ground noise.

 

[AnalogSteph]

I tried red to 2 and shield to 3. Same amount of hum as 2 and 1.

Weird.

Cross-check: Short 2 and 3 together. There should be silence.

Tried red to 2 and shield to 1+3. My 708p then stopped working. I had to do a factory reset on the monitor.

???

At this point I would whip out the multimeter in ACV and check whether there's any massive ground potential differences between both sides or something. I was assuming that both the PC and the speakers would be grounded to much the same PE connection, but maybe there's some electrical shenanigans going on in your mains wiring.

Thinking about this some more, if the adapter wire is just basically twin lead rather than coaxial and receiver output impedance is on the high side, the insufficient shielding may be a problem. You can make any old cable work when output impedance is just about zero.

When converting from unbalanced to balanced, the cable type to use on the unbalanced side is coaxial, the one to use on the balanced side is (shielded) twisted pair. While the location of this transition is obvious when you have an extra resistor in line to balance the impedances, it's not quite as easy with these adapter cables. Gnd+Shield --> 2+3 is basically unbalanced and should thus be coaxial, the kind that splits Gnd into 1+3 should be STP from that point on.