Hissing noise from Microlab Solo5


2013-01-19 2:59 pm
Hello, over the years my multimedia speakers with built in amp (Microlab Solo5) have developed a problem of hissing. Now it is almost unbearable. Using online tone generator I managed to reproduce how it occurs playing at low input volume and very low frequency, at say 5 Hz noise beats twice the frequency. If I increase the input volume, it sounds like white noise with fluctuations. I tested it with built in volume knob turned to middle. Turning the built in volume knob increases the noise. At high input volume noise is masked by what is played.When playing music at normal listening levels it looks like a constant white noise and I find it very irritating...

Does anybody have an idea what can be wrong?

So far I changed all electrolytic capacitors which made no difference.

Any help is appreciated :)