Atma-Sphere's Class D monoblocks

45rpmspinner

45rpmspinner

Super Member
http://www.atma-sphere.com/en/classD.html

Ralph Karsten's surprising post on another forum......

"I think it was one of these amps [another company's product] that I heard about 6 years ago at AXPONA that was really telling me we had to sort out class D and not treat it like we had SETs (which we never regarded as a 'threat'). So as soon as I got unpacked from AXPONA that year I began prototyping. I felt that since we had the engineering talent on staff it would be sending the wrong message to use someone else's module. We worked with several topologies and on the way obtained a patent. About a year and a half ago we completed our first production run. Of course we did a lot of comparisons with our triode OTLs in our system, at my home (using Classic Audio Loudspeakers T-3s) and with local audiophiles. I think the class D sounds better than our tube amps and so I've been running them at home and don't miss the tube amps at all- to my ears the class D has IMO the same liquidity in the mids and highs but is slightly more transparent (easier to hear into the rear of the soundstage.

At this point I'm of the opinion that tube power amps are on borrowed time."
 
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I think Ralph's correct regarding SS surpassing tubes, but it happened back in the late 80s/early 90s. (ymmv)

A pair of his class Ds were available a few months ago on US Audio Mart but were priced too rich for my blood.

Wondering what class D amps he heard at AXPONA..
 
45rpmspinner said:
more transparent (easier to hear into the rear of the soundstage
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That's a funny comment to make about an amp. Soundstage is primarily a fiction created by speaker placement. Not many recordings are made as purely 3D acoustic events where the venue is treated as a specific space to be captured as real.

For example: https://royerlabs.com/recording-orchestra/

That's a lot of mics pointed in all sorts of different directions. The real space can't possibly be preserved.
 
It's more accurately a sound field and speaker placement does indeed have the greatest impact.

Nice article. BTW I enjoy sitting in different places in the hall and listening with eyes open and eyes closed. The performance sounds different based on open/closed and there's also a difference based on where I'm sitting.
 
I'm not familiar at all with the GaN amp tech, and after reading ASR threads, am no more educated than I was to begin with. I suppose it's cool engineers are exploring other ways to make small electrical things, big electrical things. I would however be fairly disappointed in spending $5500 for some new tech in what appears to be a Parts Express case.
 
Rick Vestal said:
I'm not familiar at all with the GaN amp tech, and after reading ASR threads, am no more educated than I was to begin with. I suppose it's cool engineers are exploring other ways to make small electrical things, big electrical things. I would however be fairly disappointed in spending $5500 for some new tech in what appears to be a Parts Express case.
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Why would you even consider and then buy something that you know will disappoint. :crazy: :cool:
 
DesertRatt said:
That's a funny comment to make about an amp. Soundstage is primarily a fiction created by speaker placement. Not many recordings are made as purely 3D acoustic events where the venue is treated as a specific space to be captured as real.

For example: https://royerlabs.com/recording-orchestra/

That's a lot of mics pointed in all sorts of different directions. The real space can't possibly be preserved.
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Recordings made to preserve the venue ambiance and perspective are the reference, not random examples done any which way.
Dorian usually does a fine job of it as do many diligent recordists. I would cite our own Mike French (@mfrench) as a great example.
 
Pio1980 said:
Recordings made to preserve the venue ambiance and perspective are the reference, not random examples done any which way.
Dorian usually does a fine job of it as do many diligent recordists. I would cite our own Mike French (@mfrench) as a great example.
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Cool. What would be a specific recording I can buy?
 
Class D does seem to be getting better and better as time goes by. If those distortion specs are true, that skins of impressive. It would be cool to see distortion specs through various frequencies with this amp along with the dampening factor and noise floor.
 
DesertRatt said:
Cool. What would be a specific recording I can buy?
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Any direct to disk LP will have a good soundstage. Many of them have been converted to CD format. Some have been re-issued as LP's using the backup tape from the original recording session. They don't sound quite as good as the direct to disk originals. However, IMO they sound damn good,

As for purely digital recording, anything from Groove Note is recorded live to a two-track master. There is a soundstage in all Groove Note recordings.
 
DesertRatt said:
Cool. What would be a specific recording I can buy?
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I'd like to be able to mention specific examples of venue ambiance preservation recordings, maybe a good thread subject. I recall hearing some made in cathedrals that conveyed the sound of the space before the performance began and being impressed. There are labels that made a point of getting the most honest natural capture of the ambiance with the performance.
Mike has made many of his reference quality recordings available for digital download, PM him for availability.
 
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Lavane said:
Class D does seem to be getting better and better as time goes by. If those distortion specs are true, that skins of impressive. It would be cool to see distortion specs through various frequencies with this amp along with the dampening factor and noise floor.
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I have commented many times on the Allo Volt+D as being a budget-priced high quality implementation of the TI TPA 311# class 'D' chips for a taste of what the tech does well.
 
Pio1980 said:
I'd like to be able to mention specific examples of venue ambiance preservation recordings, maybe a good thread subject. I recall hearing some made in cathedrals that conveyed the sound of the space before the performance began and being impressed. There are labels that made a point of getting the most honest natural capture of the ambiance with the performance.
Mike has made many of rhis reference quality ecordings available for digital download, PM him for availability.
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Understood. Back in the 70s I had many of those Sheffield LPs and the Tam Henderson LPs, binaural recordings, and whatnot. But that's, of course, in the category of "specialty recordings." A thin library at best. If people say that is what the Atma-Sphere honcho uses as a reference, that makes his comment more understandable. "Using very specially recorded material.....etc, etc, etc, "
Thanks!
 
Regarding D2D LPs, of which I've more than my fair share, while all are live uncut performances most of the jazz and other nonclassical ones are studio recordings, i.e. not on stage. Some are not as spacious as the best commercial recordings and many are not all that musically stimulating. However numerous excellent jazz artists made D2Ds.

All the RR recordings are pretty damn good, both sonically and performance wise,
 
Pio1980 said:
Recordings made to preserve the venue ambiance and perspective are the reference, not random examples done any which way.
Dorian usually does a fine job of it as do many diligent recordists. I would cite our own Mike French (@mfrench) as a great example.
Click to expand...

The Delos label also falls into this category and who can forget Chesky's fine work.
 
nailer said:
Regarding D2D LPs, of which I've more than my fair share, while all are live uncut performances most of the jazz and other nonclassical ones are studio recordings, i.e. not on stage. Some are not as spacious as the best commercial recordings and many are not all that musically stimulating. However numerous excellent jazz artists made D2Ds.

All the RR recordings are pretty damn good, both sonically and performance wise,
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I long ago disposed of my LPs, and I doubt my memory of those D2D LP SQ is reliable or valid. My question is this: How many mics are involved in those jazz recordings that were D2D? My "guess" is that they are not simple two mic recordings, but were multi-mic'd in much the same way as all studio recordings. To wit: 3 or 4 mics on a drum kit, 2 mics on piano, a mic on every horn and so on down the line. When those are mixed and mastered, any sense of an "actual" space - be that a studio, hall, or closet, is lost. The space recorded is strictly local to that mic/channel on the board. 20 channels like that mixed down to 2 for stereo does not preserve any real space. It's just a hodge-podge of spaces. The engineer will add his own reverb as he sees fit. In multi-mic recordings the space you get is the reverb added on the board.
 
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