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SS amp mosfet 'haze' - ever experienced this?

Tried a new amp in my system on the weekend: the well-reviewed Gamut D200 mkIII (partly based on HP's great review), a single-mosfet SS design. At the dealers' place, it sounded great (speakers were Wilson Benesch Discovery, an isobarak, lower-efficiency design). I can't use a tube amp right now (unfortunately!) due to pending child and the system is on a LOT (2-ch/HT mix), so am looking for the most full-bodied SS amp I can find (prefer fully balanced design to match my modded SF Line 3 pre).

Well, to my surprise, the amp did NOT work out as well at my place. My speakers are 97db Coincident Total Victory. Yes, it was full-bodied, but I was definitely aware of this haze, or veiling around each note. I have a friend who designs amplifiers, and he said that this is inherent of mosfet designs. I called Israel (Coincident) and he was not surprised that I only heard this once I got back to my place, due to the high resolution abilities of my speaker vs the speakers at the dealer's. I guess I will be sticking with my Sim Audio W-3, as it is much 'cleaner' on my system (given that I must stay with SS). Too bad, 'cause my Sim W-3 definitely has the edge in clarity, but the Gamut was a touch more full-bodied.

Has anyone else experienced this 'haze' with a mosfet-based design? I admit, those with higher-efficiency speakers like mine (97db/14ohm) probably are NOT using higher-powered mosfet designs anyways, but I would like to know how others feel about mosfet designs and this issue I had.
sutts
sutts OP
700 posts
 
Wow- a response almost a year later on my original thread- thanks Kalan! OK- you might have something with the Super E/Gamut- interesting observation- what preamp; interconnects; and speaker cables though??
undertow
1,033 posts
 
I always liked Bi-polar designs over mosfet.. Don't know why but they are more organic sounding, mosfets have a more envelope sound to them and sometimes sharp, basically Mosfets were all the rage I remember with big name audio companies in the 90's and I tried a bunch out, it was kinda a trend like the Class D stuff etc.. going on right now, I find the new Digital designs to sound similar to the Mosfet designs to be honest, so its kinda a new twist on that sound, Cars sound best with mosfet in my opinion, at least the bulk of the designs I heard in the 1000.00 to 6000.00 range of amps.

There are a few big designers still using mosfet stuff, but honestly if you look around at the more expensive and discrete hi-end stuff its exclusivley bi-polar I believe.. I could be wrong but anyway thats what I see for the most part. Companies like boulder, gryphon, Mcintosh, Belles, McCormack, Odyssey etc.. that are the most mentioned and respected amps all seem to use bi-polars.
weez
14 posts
 
Interesting read...missed it first time around.

A mosfet operates more like a valve (tube) so it is no wonder that many have claimed they sound more 'tube like' than bipolar's. And they do- most of the time.

The 'haze' or 'mist' isn't a characteristic of the mosfet; it's a characteristic of the implementation. I think it was Sam Tellig that coined the phrase 'mosfet mist'. This from a guy who raved about the Unison gear that uses tubes and mosfets. Go figure.

By the way, Belles uses mosfets in the 150A Hotrod. John Hillig uses mosfets exclusively; as does Frank Van Alstine. None of these amps sound 'hazey'.

WEEZ
kalan
185 posts
 
Sutts: Yes, I took a chance on answering a thread that had not had activity for a year. Interesting topic, though. You asked, "...what preamp; interconnects; and speaker cables though??"

Pre-amp = First Sound 4.0/Paramout Plus upgrade
Interconnects from CDP (Ayre CX-7) to pre' and to power amp = Shunyata Altair.
IC's from TT rig (TNT 3.5/SME V/Benz LP) to phono stage (modified Luckaschek PP-1) = Audience Au24.
Speaker wire = Shunyata Andromeda

BTW, the First Sound/GamuT combo is fantastic. I expect a pair of Gamut M200 monos to arrive any day now.
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