Gallium Nitride GaN Class D Amplifiers

A friend of mine brought over a set of AGD monoblocks to try in my system for an afternoon. They performed extremely well for their cost (?$8K). Natural sounding and dynamic. I was comparing them against my Audio Research Reference 160m monoblocks. With the rest of the system being Audio Research Reference, the substitution was not a huge difference in sound quality. The AGD did not render the treble as well.. but for the price great deal. I would probably identified more differences if I had them in my system for much longer… but they did a good showing for themselves.

The reason I mention that the rest of my system did not change is that if you substitute one component of a carefull crafted synergistic system and substitute one component, it can often maintain its character. But switch two or three and the whole can fall apart.

@jfrmusic, the dual mono stereo (DMC) unit is $4000, not $5500.

I do sell ultra monoblocks as well that are more expensive and can be configured to be $5500.

Reach out with any questions.

@tvad 

Since you have had direct experiences with these two amps I would be very interested in more specifics of the SQ and character of the Atmosphere and AGD amps. .Did you auction the AGD Tempo or the mono blocks?

@mapman 

From the many reviews theses amps may provide a more Class A / Tube like sound character which would be attractive to me.

I had demo of Atmasphere Class D followed by Atmasphere tube amps at CAF 2022. The two sounded more similar than different so that is a good omen for the tube amp camp.

i also heard AGD at another Audiogoners house who also ran Linear Tube Audio amplifier. LTA is a tube amp that does tubes in a way that resembles very good SS or Class D amps in general. Very good sound but more towards the tonally neutral side. Atmasphere amps have just a bit more touch of tube like “PRAT” which many audiophiles will find very desirable and harder to find outside of actual Tube gear.

@jfrmusic of course the speakers matter a lot as well. Did you mention what speakers you are running? Thanks.

@jfrmusic, I have not heard the Atma-Sphere GAN amps. I mentioned having auditioned Atma-Sphere OTL amplifiers; specifically, M-60 mono blocks.

I auditioned AGD Audion mono amplifiers.

They share common characteristics of naturallness, tonal richness, excellent frequency balance (actually I think the AGD Audion had slightly better balance), and an expansive image. It’s been a few years, but my fuzzy recollection is the AGD Audion amps were more tonally neutral. The Atma-Sphere M-60 always struck me as pleasingly warm in tone, but not syrupy. This is a wonky comparison, though, because I have no idea if the Atma-Sphere GAN amps convey the same house sound. Maybe someone who has heard both will respond  

Preamp was SMc Audio VRE-1C. Loudspeakers were Audio Note AN-E/SPe HE (95db, 6 ohms).