Gallium Nitride Class D Amplifiers

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JFRMusic

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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?
 
The AGD room at the Florida Audio Expo has been a favorite of mine for a few years.
 
I heard the ADG with a speaker I'm not familiar with, I believe the name was Ocean Wave. This was at a show, I thought the sound was good.

One or two members have the Atmosphere and Ralph pops in from time to time.

Future Audiophile reviews a lot of Class D but they really seem to push them. They don't try to hide the bias.

Not long ago I was hunting an amp and didn't want one that weighed 100 lbs. My amp then weighed 65 lbs. the replacement weighs 107. Not looking forward to moving it again but my ears are happy.
 
Love my Atma-Sphere “Class D” monoblocks. Light weight, cool running, more powerful than my DIY Firstwatt amps. These amps have linear power supplies, and have both RCA and balanced XLR inputs.

I have 95 db speakers, so 100 watts is great, in fact I use -10 db adapters. I do plan to get the pre-amp adjusted (resistor change for -6 db).

Being class A fan previously, I use a tubed pre-amp, but the amps run great straight from the DAC. Ralph did a great job designing, and voicing, these amps.
 
Bones13 said:
Love my Atma-Sphere “Class D” monoblocks. Light weight, cool running, more powerful than my DIY Firstwatt amps. These amps have linear power supplies, and have both RCA and balanced XLR inputs.

I have 95 db speakers, so 100 watts is great, in fact I use -10 db adapters. I do plan to get the pre-amp adjusted (resistor change for -6 db).

Being class A fan previously, I use a tubed pre-amp, but the amps run great straight from the DAC. Ralph did a great job designing, and voicing, these amps.
Click to expand...

Yes, I have the Atma-Sphere Class D monos too. I'm very pleased with them after previously using SET tube amps. No regrets in switching.

For me, the "Class" of an amp or whether it's tube or ss is irrelevant - it's just the sound that matters and how much enjoyment I get from listening. I home-auditioned many ss amps and chose a Purifi Eligentakt based one that matched or bettered the others and my earlier SETs. Recently I bought the A-S amps and there's very little difference though perhaps (hopefully) I'll notice a bigger difference when I upgrade my preamp.
 
When Merrill went to the Element series the amps went out of my budget reach. I have still yet to hear one.

I did get to audition his former top of the line monoblocks in my system. I wanted to like them. I heard a set at Axpona driving Sadurna horns and the sound was incredible. In my system they were fast and clean, neutral. I was using Pass at the time and maybe the contrast was to much at the time. I just wasn't engaged.


GSOphile said:
No mention of Merrill Audio (which seemed to make quite a splash several years ago)? Not inexpensive though.
Click to expand...
 
I got it in my mind (after watching some firstwatt SIT4 amp reviews) that I had never played my DIY DIYAudio VFet amp with the new tube Pre. Previously, I had only played it via the passive volume control on my previous Bricasti DAC. The VFet has a 10-12 watt power output. (vs 100 watt for the Atma-Sphere Class D amps) and stereo vs mono block.

My VFet is a Sony VFet amp using an input card that uses the AD 977 chip. As I use balanced interconnects from Pre to the Atma-Sphere amps, I utilized a Jensen transformer box to convert to the single ended of the VFet.

First, the Modwright tubed Pre amp really sounded better with the low powered VFet amp than from the Bricasti.
Secondly this amp needed about twice the volume dial turn than the Atma-Sphere amps (and I currently use -10db attenuators on the Class D amps)

Sonically, the VFet is a sweet amp, with a marvelous midrange. However, it was a clear second in comparison to the clarity, extension, and "jump" factor of the Atma-Sphere Class D amps. And the midrange was still sweet and clear. The VFet sounded a bit "smeared" vs the clarity of the Class D. VFet went back into the closet.

My speakers are 95db speakers, perhaps 99db+ speakers would be better to compare these amps.
 
JFRMusic said:
Orchard Audio offers a 250 watt Amp
Orchard Audio's base model is around $2700
Click to expand...
They make 150w models starting at around $1800 iirc. I have a pair of the older 150w monoblocks, they are transparent and can drive 2 ohm loads, so just about any sane/competent speaker. No need to function as a heater here in FL.

cheers,
AJ
 
I had my Dartzeel NHB 108 model 1 and Orchard audio at my house and both at a friends house. The Daetzeel was notably better on many levels. My friend still bought the Orchard as it was good, and $2700 compared to over $12k used Dartzeel.

I also had the Atmasphere mono at my house with the Dartzeel. I don't know anyone could tell them apart. Very close on all levels.

I wonder what a Atmasphere would do next to a $70k plus SS amp. I see people swap out these very expensive amps all the time. Its a love fest for a while. Then they trade it in and share their shortcomings.
 
Kingrex said:
I had my Dartzeel NHB 108 model 1 and Orchard audio at my house and both at a friends house. The Daetzeel was notably better on many levels. My friend still bought the Orchard as it was good, and $2700 compared to over $12k used Dartzeel.

I also had the Atmasphere mono at my house with the Dartzeel. I don't know anyone could tell them apart. Very close on all levels.

I wonder what a Atmasphere would do next to a $70k plus SS amp. I see people swap out these very expensive amps all the time. Its a love fest for a while. Then they trade it in and share their shortcomings.
Click to expand...
Many times amplifiers are poorly paired up, wrong pre-amp is mostly one reason for bad sound or wrong amp for load.

Easy to have misconceptions on audio equipment without serious due diligence ..

I few years ago i went thru quite a few class D amplfiers , compares with different pre amps and loudspeakers. Could never get over the odd Timbre of them , non stayed.

This new cycle of class D magic i have yet to try , non has dropped in and not going thru another buy and sell cycle with them until i really hear one convincing enuff , hasn't happen yet from listening at shows ..

Regards
 
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JFRMusic said:
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?
Click to expand...
I have two AHB2 running in bridged mono and love them.
I recently “downgraded” my electronics (moved to smaller footprint and lighter amps, preamp, and DAC) and ended up with better sound.
What speakers do you own? Maybe the issue is not the amp.
 
Most of the High $ systems are matched amps and pre. It could just be justification for selling $140k in gear to get $200k in gear. Money does not matter to many people.

I personally like my tube amp. I like tubes in particular when done well. I have had tube amps I was not impressed by. I have had very few SS amps. I hear a lot of SS amps. A good friend wants me to listen to his setup again. Class A 200 watt SS with a Focal speaker. I am impressed by how well it plays. How well tuned the room and system are. How seamless the subs integrate. Its still not my flavor. Someone could spend all day pounding specification into my brain on why his system may be near perfect. Does not mean I'm not more satisfied with my open baffle speaker and tube amp that with the power tube I am using has a little hum. When its playing its more close.to optimum for me. I would not purchase audio amps or speakers because they spec well. I would buy something because I like the way it sounds.
 
Matching pre amp doesn't mean same brand , most times same brand is the lessor setup ...

You can end up with the weakness of the brand ..
 
a.wayne said:
Matching pre amp doesn't mean same brand , most times same brand is the lessor setup ...

You can end up with the weakness of the brand ..
Click to expand...
I don't understand "Matching doesn't mean same brand". It means exactly that. A CH Precison amp and pre. Or a Boulder amp and pre. Or a Luxman amp and pre.
 
It means exactly that ,a Boulder pre or CH Pre is not necessary the best Pre for their respective amps , not every company knows how to make a good SS pre amp its not simple like toob Pre amps ..

Note : Im using those brands as examples , not them being specifically so ..
 
nicoff said:
I have two AHB2 running in bridged mono and love them.
I recently “downgraded” my electronics (moved to smaller footprint and lighter amps, preamp, and DAC) and ended up with better sound.
What speakers do you own? Maybe the issue is not the amp.
Click to expand...
I must let you that I bought an AHB2 soon after release and before any worthwhile reviews. I bought it on the rave recommendation of an Avantgarde speakers owner. As I also owned AG speakers and was looking to replace my SET tube amps with ss, I took the plunge and bought it unheard. This was a poor decision as it soon (after a month of running in) became obvious that it was nowhere near as satisfying as I was used to.

My dealer kindly took it back after 3 months and kingly offered a full-value credit. This started a year-long search for a much more musically engaging and exciting amplifier to match the satisfaction-factor (without imitating) my earlier tube amps. After research and canvassing other ss recommendations for my speakers, I bought or borrowed 10 other ss amps of all Classes for home trials of between a week and a year. Some were poor and some very good. The AHB2 was an amp where the temptation was to turn down the volume rather than to pep it up - and that's the kiss of death as far as I'm concerned. It wasn't the worst, but far from the best amp. It has some admirable features - good looks, nicely built, accurately measuring, dead quiet, adjustable gain, etc - but it was distinctly disappointing sound-wise.

Of all the amps I tried, the best sound-wise were the GamuT D200 Mk III (but this caused an unacceptable thump through my 100+ dB speakers on start-up and shut-down), and the Class D Purifi Eigentakt NAD M33. Other good amps were an Accuphase Class (a little too "polite" for my linking), a Mark Levinson and a Micromega, but in the end I chose the excellent M33. No regrets, but since then (in anticipation of getting the NAD M66 streamer / DAC / pre), I've bought a pair of Atma-Sphere Class D monos - highly recommended if your speakers are reasonably sensitive and need no more than its 100 watts.

I often wonder how many AHB2 owners have bought them after reading reviews or forum recommendations, rather than by conducting extensive home trials with a number of rival amps. I'm sure they may be content with this amp - it's a "nice" amp but a little dull - and that's being more generous than I felt at the time!
 
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