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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
nonoise's avatar
nonoise
11,226 posts
 
Sutts:

I might be totally wet on this but check out Nelson Pass' First Watt series of amps-especially the new J-FET one. It has about 1/5 the distortion of MOSFETS and even though it is of low wattage, your speakers should present a decent pairing. He only makes a hundred or so and then its DIY time. He does it all himself so there is a waiting period.
jtgofish's avatar
jtgofish
525 posts
 
Muralman,
I am interested to hear about the way chip amps switch compared to transistors and why this could be a clue as to their sound.
Are there any web articles about this?
cdc
1,929 posts
 
Agree about chip amps being great but don't think they have the drive of bi-polar solid state. They just can't pass that much current.
Digital and chip amps are not the same thing. Look at measurements and digital switching amps (Class T or whatever) and you will invariably see a lot of HF hash or filtering to try to get rid of it. A well designed chip amps has neither.
kalan
185 posts
 
What are chip amps? Could some one please explain/clarify.
kalan
185 posts
 
Sutts, Yes the Super E III's do tend to mate with a lot of different amps. You are lucky to live so close to "Izzy's" there in Toronto. I visited Toronto two or three years ago and phoned Israel Blume to get a tour of the Coincident factory. No go. He said that there were no Totals, Supers, or Victorys in house to hear, etc.
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