audible noise from amp

[stopdrpnro 0]

i was adjusting things on my treo ssx250.2 amp and noticed their is an audible noise coming from the amp. sounded almost as if the internals were squeaking to the music. thing is i don't htink it' s the amp i replaced the treo temporally with a us amps amp and it did it also . i'v enever seen or heard this in the past anybody know what the problem could be?

[johnecon2001 82]

Just the capacitors charging and discharging. Most amps do it.