Accupgase c-200x preamp - high pitched constant stereo tone

[johnson.tc]

Any advice or ideas to getting rid of constant blaring tone? I was let down by our audiophile friends in Japan, waited a month for a “perfectly functional” piece of gear and,… it be broke. Preamp ain’t workin’

My accuophase p260 and p102 amps are 100% operational, cables and interconnections, great, source, great. (iPad streaming tunes through tidal direct connect to amp)

Once I use my preamp as the go-between, as soon as I engage the amp, (there’s a source on/off button on the preamp) I get a constant high pitched tone, no music, both ears.

Same with headphone jack.

Is this a ground issue? Something grounding out somewhere?

Once again, amp directly, …audio bliss. Hook up my 200x (with excellent rca cables), and smile turns to frown. No music, just constant “beeeeerrp” thru both speakers. I’m definitely stumped on this one. And yes, it’s set to 117v.

 

[zebulon1]

Start at the power supply.
It has four regulated supplies.
It uses op-amps.
Maybe some misguided feedback?
Find a good operational manual and read the fine print. I have several pieces of Accuphase gear and know its difficult to understand the connections and operation.

 

[johnson.tc]

Start at the power supply.
It has four regulated supplies.
It uses op-amps.
Maybe some misguided feedback?
Find a good operational manual and read the fine print. I have several pieces of Accuphase gear and know it’s difficult to understand the connections and operation.

Thanks!!!
I’ll trace the route. It’s frustrating, this baby is complicated.