Didn't know where to put the topic, so hope it's the right place
I've got a pair of active speakers ESI nEar08 and it has some hiss in the tweeters that's just so annoying as hell.
Added some large caps to power supply, replaced ceramics in ps with mylar, but no effect, disconnected the preamp section from power amp, almost no hiss, so i guess the problem is in preamp section. Replaced JRC4558 with NE5532, no effect, tried ground loop braker with resistor and cap, no effect.
Pictures of board https://picasaweb.google.com/1039189548 ... /ESINEar08
Schematic of preamp (not full, after is commonly used active crossover for highs and lows and the to power stages, wich is pretty much the same as described in TDA7294 manual)
Hope to get some help here