Hi there,
I built 2 MU 524 two months ago, tested them, everything went fine.
I wanted to use them this week and one of them had 12dB more noisefloor than the other and weird noises coming out of it.
here is a link to hear what is coming out of the unit
Left channel is the one wich seems ok, right channel is the one with the issue
http://gofile.me/6MV5G/pL4IjCWVpPlease let me know if it sounds like something you allready know
Best regards
Cdp