Not sure what's going on w your set up, but Peachtree works fine on high sensitive speakers w no noise. Something is wrong w/your unit if there's an audible hiss, even w your ear to the speaker. I have a pr of excellent Zu Omen @ 101dB and 0 noise is present w the 125 or the novaPre/220 for that matter, although the 220 is way over-kill.
Also not sure whom you spoke w/at Peachtree, but if someone told you that our class D amps inherently produce more noise than a standard A/B, they were simply wrong.
Please send your unit in and we'll get it tested.
Best wishes,
David Solomon
davids@peachtreeaudio.com
Peachtree Audio