Hi, We just purchased a new pair of M700 mono’s and we are having issues with ground loops and a high frequency sound coming from my PSB Synchrony One speakers. I fixed the ground loop by plugging everything into the same Furman PST8 power strip. But I have a very faint high frequency sound coming from both speakers when I use my high end desk top computer that I use as a music server. I custom built it with a high end, low noise power supply as well as a high end motherboard. My DAC is a Luxman DA-06. My preamp is a Pass Labs B1 that I built.
I tried different RCA interconnects but there was no change.
I tried a cheater plug on my computer, no change
I tried shielded power cords and power cords with ferrites but the sound remained.
I moved the computer about 4 ’ away higher up but no change.
I tried an AQ Jitter Bug and an Uptone Regen with a second Jitter Bug plugged into another usb port. but no change. My usb cable is a Wireworld Starlight Red.
I had issues with my Pass Labs X250 amp and a Parasound A21 amp. If I can’t figure it out I will have to return the amps which is too bad because they sound great.