Model 200 amps until I read the several threads here about their hiss problems.

May I ask, why exactly would these amps hiss? Users here have said that their 755's, etc do not hiss, but the Model 200's will hiss on exactly the same system. Why would this happen, could anybody please speculate?

Thanks in advance...

Since I don't consider the M200's to have a hiss problem (the pair driving my Studio/60's certainly don't), I did some digging through threads to see what sorts of hiss problems have cropped up here in the M200 forum. Many of the cases I've seen have been the result of ground loops or other equipment (space heater, dimmer) on the same circuit. As to why an M200 would be affected by a ground loop that didn't affect a 755, I'm not sure.

I don't see the several threads. In the only one with the word hiss in the title, I spoke of mine having a slight hiss that was only audible if you got your ear within two inches of the tweeter. The surrounds in my setup have the same degree of noise, but they are driven by my receiver, so it ain't the M-200's.

Yes you are correct, I should have said several members and not several threads - and even then, not all the members that mentioned the hiss considered it much of a problem or design defect. Looking again, I really only see two threads that talk about this at any length:

http://ubb.outlawaudio.com/ubb/ultimatebb.php?ubb=get_topic;f=10;t=000044#000007

http://ubb.outlawaudio.com/ubb/ultimatebb.php?ubb=get_topic;f=18;t=000127#000000

The first thread listed above was the one that really got me worried. Those comments there from alzy101 actually stopped me from buying the M200's, well at least so far.

Does anybody have any idea at all why the M200's caused such a significant hiss problem in that system, whereas the 755 in the exact same system would not have any hiss issues at all? Very curious about that...

It's hard to say with the information at hand. It could be that alzy101's amps were plugged into a different circuit, or that their interconnects were routed differently than previous amps and got tangled in some power cords - hiss at a distance of 12" from the speaker isn't difficult to produce with cabling, particularly with high efficiency speakers (I've done it with my Paradigms, which are pretty middle of the road on efficiency, and fixed it with some wire management). I'm not sure what speakers alzy101 is running, but yaffstone has Klipshs, which tend to have very high efficiency ratings and are therefore easily susceptible to minor system effects. I will offer this bit of first-hand experience, though: I'm running a pair of M200's and a 750 (the 755's predecessor), and the amps produce no audible hiss even with an ear at the grille cloth.

My 2 M200 are dead quiet, no hiss at all from my PSB Image Towers, and as gonk said, even with an ear at grille cloth.

Thanks to everyone who has replied so far. Perhaps I should order a bunch of these M200s after all!

So is it true then, that alzy101's very bad experience with the M200s was unique? Has anyone else, AT ALL, had any hiss, or any other problems whatsoever, with the M200s? Or is the general concensus that these little amps are well worth it?

5 M-200's, 0 Hiss

you can get a hiss from any system depending on wiring. i would say the hisses people experienced are not due to the m200s but more of an upstream issue.

I reiterate: 5 M200s, no hiss unless you are very very close to the speaker (Dynaudio). I am very pleased with mine and would not hesitate to buy more (7.1?) Good luck.