Having a problem with my setup - when pre and power amps are on, i hear a very soft but high pitched sound from both channels.
Would very much appreciate some advice on this issue.
My (initial) setup: Rotel 1080 power amp, Rotel RSP960AX Pre Amp.Mirage F2 speakers, Tara Lab interconnects, QED Qudos cable. Rotel equipment was purchased 2nd hand, from a reputable dealer. With this setup I would hear a high pitched sound from both channels if i placed my ear right up to the speaker. The sound was practically inaudible, and so it didn't worry about it.
I recently upgraded the pre-amp to a Rotel RTC-965, also purchased second hand (but not from a dealer). Pre amp was in as-new conditioned, never used apparently. Now, with just the pre-amp and power amp on, i can hear the sound within a few metres of the speakers, providing the room is quiet. It appears to be higher in pitch.
At first i assumed it was a grounding/power related issue, so i 'invested' in one of those circuited, isolated power boards. However this has made no difference.
To confuse(?) the issue, i have found one instance where the sound is eliminated. If i select a source with is connected via optical cable (SPDIF connection to my MD deck) then the sound stops. Otherwise, it is always there regardless of wether sources are switched on/playing or not.
Grounding problems are always low frequency noise; typically 60Hz hum. It sounds like you might have a transformer that is making the noise. Switch back to the other power amp to isolate the problem. After that it is probably going to require a technician to solve the problem. Call Rotel for assistance.