I've had the Orchard in my system twice..for a week each and it is a great sounding amp...but as we all know, it ultimately comes down to personal preference.

Fortunately, the amp is on tour and if you join the tour, you can try the amp for a week for just the cost of shipping to the next person.

Go to Steve Hoffman Forums and search the following thread:

Orchard Audio Starkrimson Stereo Ultra Amp Tour

Fronting the Audions with a Primaluna EVO 400 pre-amp is the best of both worlds. .

@aball

After reading your last message, I am even more puzzled.

Who is he using GaN in linear mode???

Honestly, it makes no sense.

Also, instead of continuing this conversation via potentially misread posts, please give me a call anytime and I will be more than glad to see where this disconnection between whatever written and whatever implied, is.

@aw-agd

If you read my post you will see that I’m assuming linear operation. I made the same mistake you did: I didn’t read carefully.

Also, it turns out you actually agree with my statement you said you disagree with, since 800k is high frequency.

And finally, I’m a PhD EE in power electronics who designs converters using GaN, so I’m already quite familiar, but thanks for your concern.

@aball 

I'm sorry, but I have to disagree with your statement that "They have low parasitics, but that only applies at high frequencies, not audio." The statement is completely inaccurate and misleading. The Class-D output stage runs at high frequency (our GaN modules at 800Khz), and the output MOSFET, whether Si-based or GaN-based, must have extremely low switching losses to operate efficiently. Any "parasitics" impact the efficiency and purity of the switching waveforms, causing slope variations, overshoots or undershoots during the transition. All of these factors affect the quality of sound reproduced. To better understand the fundamental principle of operation, it would help to look at the principle of operation of a switching amplifier (CLASS-D). Many articles are available online that can help you understand this better.

A while back I asked John Stronczer at Bel Canto about the GAN amplifier modules. His take was the folks at Hypex have a lot of experience with, and have done a lot of research with the NCore modules, and if there was an advantage to the GAN’s they would be in the forefront of their implementation. I’m not in tune with the industry like John is, but for what it’s worth, I do know Bel Canto class D amplifiers sound extremely good and natural. I’ve owned several over the past 10 years. Presently, I’m listening to a Rogue Audio Pharaoh 2 that also uses Hypex NCore class D modules, and which also sounds quite good in my system. I think it’s as much about the overall implementation as it is about the amplifier module in the circuit. Just my two cents worth. YMMV.

What SQ characteristics do distinguish from the auditioned Class D Gan amps that cause you to still prefer tubes. I suspect I would agree with you and pick tubes but for my rooms allergy to heat.

Have you ever experienced a class AB amp that got you closer to your tube preference ("soul"?) than a Class D Gan? If so, which one(s)?

#1 on the list was 3D soundstage. Depth was more convincing using a 300B SET tube amp.

#2 was texture. The tube amp conveyed a bit more.

Regardless of what chip amp I’ve auditioned, they all sounded a bit sterile and artificial compared to the 300B tube amp. The AGD Audion GAN mosfet amp was the least so.

I have never experienced a Class AB solid state amp in my system that came close to a tube amp. I have heard Class A that approached a tube amp - Pass Labs XA-30 and XA-60.

@marco1 , @tvad 

What SQ characteristics do distinguish from the auditioned Class D Gan amps that cause you to still prefer tubes. I suspect I would agree with you and pick tubes but for my rooms allergy to heat. 

Have you ever experienced a class AB amp that got you closer to your tube preference ("soul"?) than a Class D Gan? If so, which one(s)?

I am always interested in reading other peoples opinions on various components.  And so many people mention reviews.  I find that most people really have not heard components that consistently outperform most components.  I have said this over and over, learn what makes sound do what it does and then you can cut through so much of this and know how to find a component that performs in all systems.

BUT hey, what do I know anyway.

Happy Listening.

GaN FETs are for high frequency (>500 kHz) switching circuits and are not really meant to be run in saturation with a Q point.  They have low parasitics, but that only applies at high frequencies, not audio.  Using them is more marketing than any intentional advantage over a MOSFET.  There are too many other factors involved to attribute sound quality strictly to the output devices.

I don't represent Orchard, to make sure that's clear. I recently pulled the trigger on Orchard's Starkrimson Ultra 2.0 DIY kit with dual power supplies. So it is technically the DMC. It was a breeze to build and the questions that did come up, Leo was there to help and he is a pleasure to deal with. It is refreshing to be able to speak with the designer behind the equipment like Orchard, Rogue, Southerland, to name a few. There was a question earlier about being balanced, they are , but he has an adapter available if you choose to go that route. I am driving it with a Rogue RH5 preamp with Telefunken NOS 12au7 tubes and Martin Logan XT F100 speakers. Soundstage is deep wide and tall, separation between instruments and vocals very impressive for half the cost of the competition. And no sub needed.

I play the Technics SUG 700-2 which is around $3,000. It looks and sounds great I can't imagine anything sounding better.

Technics SU-G700M2 integrated amplifier | Stereophile.com

@marco1 all good, just not for you. I am firing up the tubes right now.

And if my post makes no sense now it’s because you just edited yours.  Now I have really no idea what you are talking about.  But that’s ok.  Just enjoy the music.

@audio_is_subjective64 not quite sure what we are debating here.  My point since posting initially was to say that I didn’t think my Class D amps sounded like or as good as my tube amps.  If you’re certain it has something to do with synergy, my speakers, or my other components not even knowing what they are then I guess you’re a pretty smart fella.  I think I know my system a little better than you and can assure you it doesn’t.

@marco1 Sure I get it. It did not work for you, however many others rave about them. Many people say the same about Class D and G (Benchmark) amplifiers I rather enjoyed my BC e1x (daughter hijacked it). It just wasn't for you. Having Cardas Clear makes nothing fool proof. I enjoy my tube system also.

Therefore what I perceive as a lack of soul, I can only attribute to the change from tube to Class D amps.

@tvad “Nevertheless, I believe AGD Productions GAN amps (and I suspect Atma-Sphere GAN amps as well), are worthy of recommendation and audition.” I agree that they are worthy of audition.  I quite liked the AGD amps when I heard them at CAS this year.  Sorry to say not quite so much for the Orchard. I liked the Atma-sphere the best out of the three I’m just not ready to recommend as a substitution for a tube amp though.  Hopefully they will continue to improve.

@audio_is_subjective64 by “other synergy issues”  are you referring to other components in my system?  If so, what I can say is the only thing that changes during my evaluation of my Class D amp is the amp itself.  Everything else including cables, Cardas Clear btw, remain the same.  Therefore what I perceive as a lack of soul, I can only attribute to the change from tube to Class D amps.

@marco1 I suspect there are other synergy issues. I rather enjoy my GaN amplifiers, I do not put them in the same category as my tube amps I do think they are very close. Love the detail. YMMV and I only have OCC copper IC's and speaker cables in the GaN system. 

I have too much stuff already but would love to find a spot for the new HiFi Rose integrated.  That company and a few others are really upping the bar when it comes to new and innovative HiFi products, or Future Fi as it is increasingly being referred to online.

@mbmi, It's interesting that you mentioned the Pascal module as a step up, having heard the Pascal in Aavik, Axxess, and JRDG amps I think you may be correct as those amps all sound top shelf.

@marco1, thank you for specifying the amps.

Interestingly, two of those...AGD Productions and Orchard Audio...were two I also auditioned about four years ago.

I arrived at the same conclusion as you did.

Nevertheless, I believe AGD Productions GAN amps (and I suspect Atma-Sphere GAN amps as well), are worthy of recommendation and audition.

@tvad The three Class D amps that did not meet my expectations were AGD, Orchard and Atma-sphere, the 3 amps brought up by the OP.  I currently own A/S OTL and Conrad Johnson amps and recently sold some Pass amps all of which I am comparing to.  Over the years I’ve also owned quite a few other amps, both tube and solid state, so I do have some foundation to compare to.  Like I’ve also said in other threads the GAN amps imo are getting close to the sound of tubes.  They’re just not there yet. Whether they ever will is not for me to say.  The easiest way to explain it and what I have also said before is that they don’t have the “soul” of a tube amp. There are of course several pluses.  They’re light weight, run cool, and in some cases a good value if that is what you’re looking for.  Again, sorry to say they just don’t sound like tube amps.  I had hoped they would.

Do yourself a favor and just find the right amp.  I went the Class D route and now sorry other than it will probably be my summertime amp.

@marco1, you have made this comment in different threads.

I respect your opinion, and I made a similar decision, but I hope you won't mind if I ask you to share some details.

It's helpful to readers if specific Class D amplifier(s) are discussed, because akin to other audio components, chip amps (I use the term chip amps, because not all are Class D) don't sound the same. At least the chip amps I've heard in my system had different presentations and characteristics.

Which Class D amp(s) are you referring to that did not meet your expectations?

Just commented on your too heavy to lift thread. Do yourself a favor and just find the right amp. I went the GAN Class D route and now sorry other than it will probably be my summertime amp. It just amazes me how to some people they sound like tubes, or even better. They just don’t. Of course that’s just my opinion like everyone else’s. YMMV.

I have the Technics SU-G700M2 which uses GaN FETs and it's really nice sounding. No etch, great extension, slightly warm, lots of PRAT, great tone, you name it, it's got it. A keeper if there ever was one and it got me off the audio merry-go-round.

All the best,
Nonoise

My Audions are fronted by a Primaluna EVO 400 pre which has been in my stack for 2 years. This sounds good, but in a few weeks supposedly I will be receiving a Holo Audio Serene KTE pre. My DAC is a Holo May KTE, and the Serene is supposed to compliment the May quite well. However, I am a little apprehensive. New Record Day’s Youtube review of the Serene said something to the effect that the Serene took the totally clear window of the May and smashed that window out of the way which is what the Audion already feels like it is doing. Clear I like - "clear light" as in the famous old time LSD could be harmful to your health. LOL

I own the Peachtree Gan 400 amp.....Match it with a nice tube preamp and you have a beautiful , musical sound. Nice.  OR go with the Pascal Module that Aavik , Axess and Gato have for a step up in SQ.

@bhvf , care to say what the old and new cables were?  It might help others who happen to be using similar cables

I recently purchased a Hifi Rose RA180 that I have paired with Focal Diablo Utopia standmount speakers and an SVS sub. It also utilizes GAN transistors and had some interesting features such as bi-amping capabilities, BTL mode for difficult speakers, selectable tone controls, and a dedicated sub out.

I also really like how it looks on the rack and stacks up well with the highly rated and equally gorgrous Hifi Rose RS130 streamer. 

I wanted to give an update. I needed to drop off a couple DACs I was trying at my local AGD dealer. I mentioned this thread and told him about my thoughts on bass. He said he never heard that nor experienced it in his own systems with their amps. He speculated it may be my speaker cables so gave me something to try. There's a huge difference on the bass side between my regular cable and the ones he gave me. I'm shocked at the difference. I bought the cables when I had a totally different system so they may just not work with this amp and speakers as well. Crazy hobby/addiction.

A Pass XA-25 and a Had Firebottle HO...why should I care?

Check out audio group Denmark , they have very good products ,even their entry level has technologies their brilliant designers have that most Donot .

well worth checking out ,their entry level is better then most of any type of amplification per $$ dollar spent. Lots of cutting edge technologies.

I would not let GAN transistors be your deciding factor ,that is just one small influencing part of a big chain of parts . Much has to do with how substantial the power supplies are , quality of build ,and output stage . Some build pretty boxes 

look at Merrill a fine product but  put a pretty face on it with nice machined cases 

and then $25-$30k I was shocked ,just 3 years ago they were around $10k .if I am going to spend over $10 k  AAvic from theDanish Audio group makes Outstanding 

gear That get get very $$ ,But they have a entry level line that is very refined with lots of trickle down technologies  that is reasonable a integrated starting around $6k. The Danes  are known to build excellent products .I owned a class D product 

I regret selling from Gato audio very natural and musical. I think they have a Canadien distributor .their 150 monoblocks with a meter is very well respected .

check these guys out . Sorry I cannot remember everything here but it’s a good starting point.

Peachtree also carries GanFet products.

Another thing I had change with the Audions - the 10 gauge "western electric" speaker wires I had been using with the previous set up had to be changed over to 16 gauge. With the 10 gauge wires the sound was way too overbearing and difficult to get right. Sounded like a run-away horse.

@atmasphere I would love if you could try the two tracks I mentioned with your various amps and report findings. Maybe PM me? I am super curious. 

Yes. 

Aren't Orchard amps balanced input only?

Aren't Orchard amps balanced input only?

I have no experience with AGD, Orchard or Atmos-phere but I have owned a Peachtree Audio gan. 400 for a year, my local HiFi dealer had it in stock and I was able to audition it and bought it, 400 watts into 8 or 4 ohms.  I am quite happy with it, very detailed, but not bright, neither forward or laid back, more neutral. Wanted a little more power for my Magnepans than I had with my old 150 watt Threshold amp.  There may be better gan amps for a higher price but I can’t complain, quite happy with the gan. 400. I think class D is the amp of the future and they are constantly evolving and getting better, and the days of the 150 lb space heater class A/AB amps are growing shorter.  

@mapman +1, I also own the Bel Canto REF1000Ms and use them to power my distributed bass array for a bi-amp set up. No shortage of bass there and it's very fast and articulate.

When speaker designers of yore were making speakers with 32 and 16 ohm impedance damping wasn't quite as important. Back then tube amplifiers, zero feedback SET in particular known for high output impedance, were by far the norm. Nowadays with speakers being of lower impedance things have changed. It's been said by a few people I know who make tube amplifiers that the popularity of solid state amplifiers using feedback came about due to speaker designers making 4 ohm impedance speakers. Makes sense when you think about it as damping should be higher with that type of load. However, these same tube amplifier makers have said to me that anything over a damping factor of 20 makes very little if any difference. So the damping factor spec should be taken with a grain of salt as well.

I believe Most Class D amps have low output impedance which can contribute to damping factor compared to higher output impedance tube amps. That can make a big difference in how bass sounds in many cases (not all) in that the driver is better controlled and distortion lower. When I first heard my first Class D amp in my system, Bel Canto ref1000ms, it sounded like the bass was gone. Shortly after when my ears adjusted I realized it was all there but more defined and articulate than ever compared to several prior SS amps. A decent quality sound meter app is all that is needed to put any bass level question to rest. Ears alone may well not cut it in this case.

@izjjzi I can't speak for other class D designs. The sound varies from one class D to another more than it does with class A amps or tube amplifiers- IOW quite a lot.

But I know how our stuff sounds.

For reference I use LPs and CDs that I recorded- which helps since I know how they are supposed to sound. The bass issue you seem to describe doesn't sound challenging to me- I also play bass and keyboards (most of which are old school synthesizers) if that helps...

@atmasphere Respect and regards to you and to Alberto.

Please, it is not bass I am referring to but low-end reverb(?). The two tracks I previously mentioned involve a synthesizer and organ, not bass guitar or other. I own a pair of REL 212SX and yes, Billy Eillish tracks and others hit my chest like a truck. What I am describing is the emotion of deep notes, resonance (reverb?) that you can feel. My Accuphase A36 and PASS LABS x260.8s knocked those tracks out of the park, but were muted... benign with GaN. If this piece can be solved by GaN amplifier manufacturers, GaN will be my last stop. That said, I will soon be auditioning a new player in the GaN space (ArgentPur) some time this month or so.

No experience with Orchard or AGD, but I owned a pair of Atma-Sphere M-60s for a number of years, fully upgraded to 3.3 including V-Caps. After procuring a pair of the Atma Class Ds, the M-60s were sold and I've never looked back. The Class Ds are smoother in the top end, have better control of the bass, and are equal in the midrange, all of which is high praise as the M-60s sound great. I don't at all miss the heat output or the 24 tube anxiety of the M-60s; the Class Ds never even get warm, and I can leave them on all the time.

Speakers are Zu Druid V, which I've driven with 2 watts but sound way better with 50, regardless of room size.

On my GanFET Audions the bass was so impactful that I had to disconnect one of the two hot wires to the REL S812's. This was advised by REL if your system has so much bass that is cannot play louder than position 5 on the REL volume knob without creating excess bass.

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

@bhvf I'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. 

@izjjzi The '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.