Hello all, I know this is an older thread, however, I would like to add my experiences. I have been a long time reader, but I have never posted before- until now. I read this entire thread, and I agree with some and disagree with some.
There are very much audible differences in top quality amplifiers. Those that claim other wise are either deaf, or have no real world experience.
I presently own and/or use the follow gear. Krell, Magnepan, Harman Kardon, Cambridge, NAD, B&K, ATI, Denon, Oppo, Audio Refinement, PS Audio, Project, Thorens, Shure, Grado, Linn, Integra Research, Integra, Proton, YBA, JBL, Marantz, Infinity, M&K, Odyssey Audio, DynaCo, Van Alstine, Audio Quest, Kimber, Kenwood, Klipsch, SAE, ClearAudio, Rega, Athena, Thiel, Panasonic Plasma, Visio Razor OLED, Pioneer Elite projector Sony ES, and many others.
Pro Audio - AB International, JBL, Crown, Carver, Mesa Boogie, Orange, Gallien Kruger, Urei, DBX, Revox, Apogee, White Audio Labs, QSC, Cerwin Vega, Wilson Pro- and others.
I'm not trying to brag, really I'm not- audio is / has been a life long passion for me, I guess my dad got me started when I was kid because he was in secret electronic stuff during the Korean war while he was in the Marine Corps, he showed me the value of tube gear- beginning with Fisher.
I spent some time with several bands in my younger years- ah, if only I could relive those years.
Any way, I'm not going to down or comment on any one's post save one- And I already did that up above.
I will tell you this, no joke aside- there is a huge difference between a Krell amplifier, and say NAD. Just as there are large differences between tube and SS- it really is that drastic- the Sonic's are vastly different. That being said the same holds true with PA designed gear, it's all power with no finesse- I have directly compared my Crown K series, AB International, and QSC amps against my Krell, the Krell wins every time no matter the program material. This on both cone speakers and Maggies. One thing to note: a good pre-amp can make ANY amp sound vastly better then it really is - (given volume level of course) keep this in mind.
However, at very high spl, long term usage- the Crowns are better because it's what they are designed for, they sound good, just not spectacular, like good quality home audio gear can and will, set up correctly at lower demands (say under 300/400 wpc).
As for hiss at low volume? Heh, I'd say you have some problems with your equipment, quality equipment doesn't make a sound until you want it to. If it has noise at idle, I can only imagine what it's doing at volume. (vinyl exempt)
Of all the gear I own, or have owned, my favorite's-
Receiver- B&K AVR 507 S, beats the hell out of my NAD T785, Period, I've owned many receivers.
AMP- Krell Evo series, with a special place for my KAV-400xi integrated- so small but huge sound and power. I presently own about 20 different amps.
Speakers- Magnepan 2.7qr and 3.5r, I do really enjoy the 803's but I do not own them, for my pc- Klipsch 2.5's. I presently own 9 pairs of speakers, not including SS speakers.
CD player- Cambridge 851c, an amazing digital source, replaced my YBA. However, my all metal (even the transport) Marantz CD-1 (first ever cd player made) still sounds quite good.
DAC- PS Audio
Blu Ray- Oppo
TT- Thorens TD-2001 / TD 321 with Shure Ultra 400S, and a tweaked Project Tube box w/ bugle boys.
SUBS- M&K I use two MX 5000 series.
What I am trying to get at here is that audio is a never ending experiment, and over the years, friends, family and ebay have been very good to me.
I learned long ago, never hang your hat on any one design, for the time will come, and something else will prove other wise.
I know.... rant.
Sorry