High pitch sound from summits

[Malle]

I can hear a high pitch suond from my right summit, the sound does not come from the panel but fron the "box". The sound disappears after about 10 min. of listening but its very irritating. Any suggestion what it might be ? I am sure that you guys have the answer

Best regards
/Malle

 

[Pcar928fan]

Probably the internal amp as it warms up...

 

[sleepysurf]

Have you tried L-R swapping your amp speaker outputs? If the noise comes from the other speaker, then the source is your amp, pre-amp, or source.