Hi All.

Post follows on from my previous one about speakers v. monitors. I learned a lot from that - thanks.

Upshot is that I got some Wharfedale Diamond Pro-Active 8.1 monitors from ebay (used)

Initally the sound was excellent - I was very pleased. But afte a week I suddenly developed a mains hum that I cant lose.

I've connected them direct to laptop via unbalanced TRS/RCA (phono). When powered and cabled up, but with the TRS jack out of the laptop I dont get any hum. If I connect the TRS to the laptop, but disconnect either of the RCAs from the monitors I dont get any hum. If I switch off the power to one particular monitor I lose the hum - But not if I depower the other instead.

Its most odd - either one seems to work OK, but not together. Because the hum resolves when one unit is depowered it suggest to me a defect in one unit.

I've had lots of help from these forums - but this is probably too big an ask. Hoping for flash of genius/insight/wizardry

Any ideas gratefully received. BTW I've had a quick peek inside and nothing obviously fried.

thanks
Tom