if you switched amps and speakers and the sound is still there - then it may be your source, or even cables, if its some kind of emi (airborne noise pollution captured by rca cabling)
sharp and piercing high pitch /frequency coming out from Harbeth C7
I have a problem with the sharp and piercing high pitch coming out from the C7 40th anniversary speakers when sometimes listening to the soprano or complicated loud passage in CDs. I changed the speaker cables from Analysis Plus Oval 12 to Transparent Musicwave which has a filter for frequency. It got better but not totally elimiated. Any solution for this ?Thank you!