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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
plelko
26 posts
 
Hey Grant,
No, I didn't, but did you hear this one, "Who is the best rapper of all time, MOS-FET!" I feel like George Constanza in the episode about the shrimp joke.
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saxo
98 posts
 
Just LISTEN to Pass X series. That will convince you there is no "looseness" or "lack of power" in power MOSFETs. I'm not trying to push the Pass, I'm just trying to get some rationality in this discussion.

Execution and circuit design. These make the difference. Many designers didn't know how to design a circuit to make these MOSFETs do their best. I like the sound of bipolars as well, if implemented correctly. It's not a matter of which device; it's a matter of design.
muralman1
1,527 posts
 
I did listen to the Pass X series amps, for a period of years. They were my mainstay in powering my system. My last was the X600. I needed the power to drive my difficult speakers. I was fairly happy with the sound. "What could be better," I asked myself.

Well, there is better, a lot better. Mosfets do draw a haze over the signal. It is a thick fog. That is in comparison with my present monos. They are leagues clearer. My X amps bested the solid states, and tube amps that I owned. There was nothing better to be expected. After all, it' s Pass, isn't it? I knew there were deficiencies, like thick midrange, and soft bass, but hey, They are beautiful amps, aren't they?

The future is here. Not everyone knows it.
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