sharp and piercing high pitch /frequency coming out from Harbeth C7

its the amp or the room

not likely the speakers - its garbage in garbage out with speakers

Thank you all for your advice. However, I tried a more powerful Amp with 300 W per channel, the frequency is stronger. I also brought the speakers to another audio shop for testing. The same tracks with the sharp freqency happened on the Sonus Faber speakers too. But the sharp frequency was lessen by the high end speaker cable with filtering so I upgraded my cables too.

I avoid turning on the volume too loud, like just turing it not over "12:00 o’clock". I agree that It might be the power supply and the electricity fuse..... and also the placement of the speakers. I have moved them and they sound better now.

Speakers > amps > CD
Are you sure it's not the CD source?

whats the track?

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)