[Trevor]

On 10/02/2018 10:16 AM, Gareth Magennis wrote:

No, I think we have our wires crossed, a la Star quad cable.

I suggested to Linda that the hum might actually be coming from the SMPS
wall wart, not the cabling.

I said that to check that, she could try connecting a different power
supply.

I said such power supply doesn't HAVE to have the capacity of the
original, which is capable of driving the inbuilt speakers.
I inferred it merely has to power up the piano so it is possible to
check whether the hum has gone away or not.

Even a smallish wall wart should be capable of booting and running the
piano, as long as you don't use the speakers.

If this experiment proved the original Wall Wart WAS noisy, she could
THEN start looking to procure another proper one.

Else, continue with the Star Quad shennanigans.



At least she said all along that the "Star Quad shennanigans" was simply
because she already had a ton of that cable, NOT because it would
actually solve anything. The real answer IMO is to put an isolation
transformer or DI between the headphone out and mixer. Changing the PSU
alone will probably make little difference. As will the "Star Quad
shennanigans" of course.

Trevor.