In my recent research for a possible upgrade to my current amp (Benchmark (AHB2) I was reading about the new higher end design for Class D. I'm very interested in learning more about these new GaN(Gallium Nitride) designs. Three companies are offering some very well reviewed products and they are not going crazy with Watts per channel:
Orchard Audio offers a 250 watt Amp
AGD a 100 watt
Atmos-Phere also a 100 watt
What's interesting is while Orchard is a new company AGD and Atmos-Phere have been around a while producing high end Tube amps. In almost every review it is noted how these newer designs sound like Class A or Tubes with all the benefits of Solid State. One reviewer couldn't go back to his tube amps after extended listening to the Orchard. No wonder AGD and Atmos-Phere are getting into this technology. It's very exciting as these amps are highly efficient turning over 90% of the power they draw into sound compared to about 78% with A/B designs and I believe even significantly lower for Class A. They run cool and usually weigh between 10-28lbs. I plan to do more investigation. Small size and light weight with decent power is very attractive. There are also mono block offerings for more power if needed. These are not cheap Class D products. They are well designed and constructed.
Orchard Audio's base model is around $2700and their Dual mono version with larger power supplies is $5500.
Both AGD and Atoms-Phere are $5000
Mono blocks for each are about twice the cost.
Has anyone had any experience, demos, etc ., with these types of GaN Class D amps?
My question is, why? I do not think other amps are embellishing the sense of power and scale. I am wondering what it means that GaN is not accomplishing the same? Is it more accurate? Controlling the drivers too well?
The sound is as good as anything I’ve had but the bass is light compared to others...or is it more truthful? I think it’s tad light but everything else about it is spectacular
@bhvfI've heard a lot of class D amps that were light in the bass. I have a hypothesis as yet unproven which is that many designers think that since the amp is so efficient that they don't have to have a beefy power supply. IME a beefy power supply is pretty important since the amp's current draw can vary quite a lot and the supply must be able to handle it with no worries.
@izjjziThe 'sound' of any amplifier has more to do with its distortion signature than anything else. If you know this then you also know as a designer to keep the distortion spectra (which is very measurable) as benign as possible.
If you get all the parameters right class D will have just as much impact in the bass as any other amplifier class. GaNFETs are not any more 'accurate' as they are switching devices. The design and how well its executed is what is important.
Gold Note of Italy has GaN mono blocks also that are quite spectacular and have sound quality that rivals the boutique builders and will save you $1 to 3k. PA-10s are well reviewed and received. Search the pages in this forum.
AGD does not make a Hybrid Tube GaN amplifier. The GaN circuits are located in the tube and it is 100% solid state GaN, pure gimmickry with some functionality.
Interesting, @izjjzi. I have the stereo AGD and feel the same about the bass. The sound is as good as anything I’ve had but the bass is light compared to others...or is it more truthful? I think it’s tad light but everything else about it is spectacular. Alberto, the owner/designer, sometimes chimes in around here as does Ralph at Atma-sphere. Maybe that’s how they sound so good everywhere else in the spectrum. SET’s often have the same issue, but I thought that was due to power. The AGD’s can handle difficult loads like Maggies and Quads.
I have had Audion MK 3’s for a few weeks now. It is the most educating experience I have ever had with a component. The difference that different cabling makes is much more apparent than it used to be. Moving around different brand cables within the component mix results in some quite unexpected advantageous relationships which were not so clearly audible in previous set ups. These modifications extend throughout the component mix.
The amps also very quickly educate you about what treatment the listening space requires. "Room nodes" are now distinctly audible to me across the spectrum. Bass nodes in particular are now more obvious as to where they are in the room and where treatment should focus.
With these amps volume can be turned up higher without bleeding the music or wearing the listener out. I feel that I have been learning more things about musical reproduction in general.
I owned the AGD Gran Vivace and they were spectacular. I had an Aesthetix Calypso linestage (tube) preamp in the chain and it was the best sound I've had in my room to date, save for one aspect - low end (reverb). Back to this in a second... what set AGD apart from the others is that they purchased all of the GaN modules that were designed for audio applications whereas all others only had access to modules for other purposes. I do not know if this has changed, but it seemed to be a true story a year or so ago. Back to where GaN fell short for me -
Enya "O Come, O Come, Emmanuel" - Opening deep synthesizer and second, John Rutter: "Pie Jesu" around the 1:02 minute mark. Both are Qobuz. What is missing? Power and emotion. My question is, why? I do not think other amps are embellishing the sense of power and scale. I am wondering what it means that GaN is not accomplishing the same? Is it more accurate? Controlling the drivers too well?
I have both a LSA Voyager 350 GaN amp and a EVS 1200 IcePower 1200AS1s. Both are dual mono in a single chassis. Both are excellent, and as good as any of the many amps I owned over the decades be they tube or SS. Sadly, the EVS is no longer made, but the Voyager is and it's a real bargain (MSRP ~$2700), AND, Ric Schultz modifies them
The Orchard products sound more compelling to me than the Atma-Sphere monos.
More power maybe? Not heard the AGD gear yet. Class D with GanFet or something along those lines is the future. The Euros have been doing it well for sometime now. It is better with warmer speakers for my money.
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.
I own both sets of amplifiers. I have owned the M-60s for over a decade and purchased the Class D around the time they came out. The Class D gives up very little to nothing compared to the M-60s, simplifies ones set up quite a bit, and if you care about saving the environment and some cash on your utility bill there's that too.
From the average audiophiles perspective the description of the M-60s by @tvad might sound nice, although I wouldn't use the term "pleasingly warm in tone" myself. From my perspective I would say both the M-60s and Class D have low coloration characteristics due to their low distortion, especially in regard to higher order harmonics which tend create unnaturally bright tones. They are both well balanced amplifiers (with AES48 compliant balanced differential circuits) that will pass the "truth" to your speakers. You will most likely find your speakers and components upstream from the amps introducing more coloration. The amplifiers themselves not so much.
As a long time Atma-Sphere customer and authorized dealer feel free to take my comments with a grain of salt.
Totally a swag guess based on personal experience but I suspect the Atmasphere Class D would sound somewhat more different from Benchmark than AGD, but the only way to know for sure would be to try both and compare. All three are very good amps so I think it mostly comes down to personal preference and how much change you seek. Sometimes you just have to go with your gut feel, or which product and company strikes you best. I think you have identified two very good alternatives.
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.
@jfrmusicof course the speakers matter a lot as well. Did you mention what speakers you are running? Thanks.
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?
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.
The benchmark is top notch. Nothing wrong with the others using GaN but hard to call a clear “upgrade”. Depends on the specific amp not what transistor technology used and what you prefer mostly. Atmasphere and AGD are popular with tube amp lovers otherwise. GaN has advantages but alone does not guarantee “better” at least based on objective measures alone.
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