GaN FET Amps vs. Traditional Class D Amps

First you would have to describe what is meant by 'traditional' class D designed amplifiers.

All "traditional" Class D amps do NOT sound the same.  You have to compare specific models.  The devil is in the details.

In general GanFet  ups the ante in terms of performance level possible. Does not mean all GanFets are necessarily better.

I have several Class D amps including Hypex Ncore,  Class D Audio GanFET, and other chip based Class D amps. Have owned "high end" Icepower in the past as well.

They are all good but each different.  The Class D Audio GanFET is the best performer in all regards.  HYpex Ncore is no slouch but sounds clearly different.  That’s just one specific Hypex Ncore amp.  There are many designs  at various price points with different power supplies, opamps used, etc.   You have to compare specific models to draw any meaningful conclusions.  

Buckeye Amps on GaN FET…

https://www.buckeyeamp.com/blog

That blog post by buckeyeamp is your typical ASR tripe. He whines that the GAN transistor shows little measurable improvement over mosfets used in most class d amps. 
 

So what? We are interested in how things sound. Like the OP I too am interested in how GANfet based amps SOUND compared to the usual Class-D offerings.

The limited amount of UCD and ice power amps I have heard so far were all smooth, clean, and lacking realism or lifelike sound the better class A/B amplifiers can achieve.

My GaN FET amps sound every bit as good as my tube amps without the heat.

Thank you for all that took the time to reply. I appreciate it. 

I know I wasn't specific and was probably confusing as well. What I meant by 'traditional' was anything that is not GaN FET based. I should probably ask an additional question. Besides GaN FET class D amps, are there many other class D types out there?
 

I should probably have stated up front that I know almost nothing about class D amps other than they typically seem to be smaller than class A/B and class A amps, they are considered to be more efficient and because of that typically don't get as hot as those other two classes, and some might say that they have less "body" to the sound or can sound lean. I'm not saying that those are fair assessments. They are just general statements. I've heard some cheap class D amps and they can sound cheap, but not always. I've heard some better class D amps (4 figures+) that have sounded very good. I haven't gotten to A/B compare any against class A or class A/B, nor have I been able to compare GaN FET based class D amps against non-GaN FET based class D amps. 

I guess one of the reasons that I asked the question in the first place is that what I'm hearing about GaN FET based amps makes it sound like it's a better technology, but better how? In what tangible way? Does it improve the sound (I know that's a loaded question - sorry). Basically I'm trying to understand what all of the fuss is about. I'm not trying to bash any particular technology. I'm just trying to understand. 
 

Thank you. 

GanFET technology and Class D amplifiers both represent advancements in amplifier design, but they have distinct characteristics and advantages. Here’s a comparison of the two:

### 1. **Technology Basis**
- **GanFET Technology**: Utilizes Gallium Nitride transistors, which offer superior performance characteristics compared to traditional silicon-based transistors. This includes faster switching speeds and better thermal performance.
- **Class D Amplifiers**: Typically use MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and operate by rapidly switching the output devices on and off to control the power delivered to the load.

### 2. **Sound Quality**
- **GanFETs**: Known for producing a sound quality that can rival Class A amplifiers, with a smooth upper midrange and controlled bass. They are often described as having a more natural sound due to their minimal feedback requirements, which helps avoid harshness [[3]](https://www.audiocircle.com/index.php?topic=183615.0).
- **Class D**: While modern Class D amplifiers have improved significantly in sound quality, they can still exhibit artifacts such as distortion and ringing, especially at lower frequencies. Traditional Class D designs have often been criticized for their sound quality compared to linear amplifiers [[1]](https://futureaudiophile.com/what-the-hell-is-a-gan-gallium-nitride-amp-and-why-is-it-changing-the-way-audiophiles-now-see-power-amps/).

### 3. **Efficiency**
- **GanFETs**: Achieve efficiencies of up to 95%, which means they waste very little energy as heat. This allows for smaller and lighter designs without the need for large heatsinks [[3]](https://www.audiocircle.com/index.php?topic=183615.0).
- **Class D**: Also highly efficient, typically around 90-95%, but may not achieve the same level of performance in terms of sound quality as GanFETs when designed with lower-quality components [[1]](https://futureaudiophile.com/what-the-hell-is-a-gan-gallium-nitride-amp-and-why-is-it-changing-the-way-audiophiles-now-see-power-amps/).

### 4. **Size and Weight**
- **GanFETs**: Their high efficiency allows for compact designs, making them lighter and easier to integrate into various audio setups [[1]](https://futureaudiophile.com/what-the-hell-is-a-gan-gallium-nitride-amp-and-why-is-it-changing-the-way-audiophiles-now-see-power-amps/).
- **Class D**: Generally compact as well, but the size can vary significantly based on the design and components used.

### 5. **Load Handling**
- **GanFETs**: Capable of driving difficult loads, such as planar or electrostatic speakers, effectively. This versatility makes them suitable for a wider range of applications [[1]](https://futureaudiophile.com/what-the-hell-is-a-gan-gallium-nitride-amp-and-why-is-it-changing-the-way-audiophiles-now-see-power-amps/).
- **Class D**: While many Class D amplifiers can handle various loads, they may struggle with very low impedance loads unless specifically designed for such applications.

### 6. **Cost and Availability**
- **GanFETs**: Currently, GanFET amplifiers can be more expensive due to the cost of Gallium Nitride technology and the relatively new market presence. However, prices are expected to decrease as the technology matures [[1]](https://futureaudiophile.com/what-the-hell-is-a-gan-gallium-nitride-amp-and-why-is-it-changing-the-way-audiophiles-now-see-power-amps/).
- **Class D**: Generally more established in the market, with a wide range of options available at various price points, making them more accessible to consumers.

### Conclusion
In summary, GanFET technology offers several advantages over traditional Class D amplifiers, particularly in sound quality and efficiency. While Class D amplifiers have made significant strides in performance, GanFETs represent a newer, potentially superior option for audiophiles seeking high-fidelity sound with the benefits of modern technology.

---
Learn more:
1. [What the Hell is a GaN Amp and Why Audiophiles Care](https://futureaudiophile.com/what-the-hell-is-a-gan-gallium-nitride-amp-and-why-is-it-changing-the-way-audiophiles-now-see-power-amps/)
2. [Orchard Audio Bosc (GaNFET Class D) vs. Hypex & Co. ? | Audio Science Review (ASR) Forum](https://audiosciencereview.com/forum/index.php?threads/orchard-audio-bosc-ganfet-class-d-vs-hypex-co.15980/)
3. [Class D Showdown: Purifi vs. Gan5](https://www.audiocircle.com/index.php?topic=183615.0)

@mcraghead - This is such a hard question to answer. I own both (AGD Audion and Nuprime AMG One) but still couldn’t tell you how the technology affects the sound. They would have to be designed by the same person for me to know. I think @mapman gave you all that can be said about this. You would need to listen to different amps and pick the one that sounds best to your ears. Good luck.

That was great information. Thank you for taking the time to provide it.  I'll be sure to check out all of those links. 

GaN operates at a much higher switching frequency and allows for less noise, higher efficiency and less distortion. There are quite a few Class D types out there and each has its own "sound" based on the designer and the quality of the output filter. A lot of Class D has a very neutral sound, for example the 3255 adds no distinct flavor at all. I find GaN to be a bit more easy on the ears and a bit more musical. Of course you can add to this with tubes in the input stage even direct heated triodes (DHT). https://quarkhifi.com/products/master-series-dht-gan-fet-hybrid-amplifier-300wpc

I'll have a lot to read this weekend. Again, thank you to everyone for adding to the discussion. 

Class D amplifiers barely scratch the surface of the capabilities of GaN semiconductor devices.  Compared to Si devices, GaN can operate a higher frequencies, higher voltages, higher power and higher temperature.  An amplifier can be designed to take advantages of these greater capabilities.  Just swapping out Si devices with GaN devices would do little to change the amplifier but if you design the amp to run a higher frequency with fewer devices then things may sound different. 

@tosnc +1

I have yet to hear any GaN Fet amp design, so can’t comment on the sound of those. My comments have more to do with my class D journey--how I proceeded amidst the pro- and con- hype.

First: I know my own sonic tastes and preferences very well. I prefer amplification that is slightly warm, definitely spacious & resonant, has a midrange that is expressive and full, and conveys the natural weight of lower frequency instruments. In short: sound that is "musical" (sounding a lot like the real thing IRL), not sound that is forensic and unnaturally detailed.

Second: I addressed my own ignorance by reading vast amounts of reviews and user comments for dozens of class D amps, new and old. At first I wasn’t much concerned with cost or availablity, but more with sound. This took months, mainly because relatively few reviews really characterized the sound of amps in ways I recognize; and even fewer user comments drilled into that side of the amp in question. Instead, there was a lot whiz/bang stuff about S/N ratio, damping fact, amperage into low impedance loads, blah-blah. Those things are obviously important, but lacking characterization of the amp’s sound, they don’t mean as much to me.

Third: I finally identified three or four class D designs that were (more frequently than others) lauded as sounding like music. The first was an ICEpower design, the Wyred 4 Sound ST-500 class D amp. I found one used and liked the sound a lot right away. I felt extremely lucky that all my homework had paid off. Next I picked up a used pair of Bel Canto 600M NCore monoblocks. Again, I liked the sound right away. Another huge piece of luck.

So I was able to find one example each of two legacy class D technologies (ICEPower and NCore) that sound really to me and were affordable. I suspect there’s at least one GaN FET design out there would fit the bill, too. My research is ongoing, but I have yet to find any affordable names to get interested in, plus the two I have (ST-500 is backup; 600Ms are in the system) are so good, I really have no need to upgrade.

PS: what started me on all this was the limitations of space I face in this home offic.e There is simply no room for an A/B class stereo amp here, much less a paif of A/B monoblocks. Class D definitely works here, with little if any heat output and far more compact case footprints.

"Basically I’m trying to understand what all of the fuss is about." 

Current flavor du jour explains the fuss. Where it goes remains to be seen. Current owners are still early adaptors. 

I fell down the Hypex NCore hole and convinced myself Bruno Putzy’s NC1200 monos sounded as good as the big Class A amps I owned at the time but, after spending quality time with them, I decided they ultimately didn’t. The NC1200 amps were simply not as natural sounding, at least to me.  As with regular Class D, advantages of GaN FET include size, cost, and lower heat.  As pointed out, there are potentially performance benefits. I am still not seeing much GaN FET with higher power ratings, although the monoblocks from Mytek do look interesting (link), and pricy. 

This isn't 1973. Today's Class D amps should be preferred by any audiophile if they want to hear what the music is actually supposed to sound like. 

@mitch2  so what what did you go back to after your ncore adventure?

I just look at reviewers reference equipment -which is an indication of what they truly like- and barely any of them use class-d on a daily basis. It never satisfies.

Although some of the recent GAN reviews may change that. Time will tell after initial enthusiasm wears off.

I own a 2K Peachtree GAN FET amp and an Aavik Pascal Module Class D amp ( the most expensive Class D Module to date @ 20K. The Aavik sounds in a different league ,HOWEVER...the Peachtree with a quality tube preamp is a delightfully musical experience. I have the Aavik to match the wonderfull highly regarded Borresen X-3 speakers......but the Peachtree drives them beautifully also and very musical I might add !

@agisthos - So at that time, Putzy's NC1200 Hypex amps were being hyped in the reviews as "better than Class A" with many adaptors happy to finally have an option for good sound with the conveniences of low heat and small size.  At first, they seemed to sound good with rich tonal qualities through the midrange and tight, powerful bass but, over time, I noticed things that just didn't sound as realistic as with the Class A and AB amplifiers I had owned.  This review (link) describes pretty much what I heard, and specifically:

"All notes were there but the illusion of musicians standing in front of me wasn`t convincing at all. The music didn`t sound inviting and involving, it was just… there.
The emotional content was missing and the tonal colours were somewhat bleached. For lovers of analog reproduction and concert goers the sound could also be quite fatiguing and plain boring."

As to my amplifiers, I had previously owned a pair of Clayton Audio M300 (Class A) monos, which I sold after purchasing the Acoustic Imagery Atsah NC1200 Class D mono amps.  When I sold those Class D amps, I purchased another pair of Clayton M300s.  Shortly after, I purchased a pair of Lamm M1.2 Reference amps, which also sounded very good but sort of ran out of steam with my low'ish efficiency Aerial speakers and so I ultimately ended up working with SMc Audio to build me a pair of high-powered monoblocks constructed from two DNA-1 amplifiers.  The two DNA-1s were totally rebuilt using SMc Audio's new boards, low-noise Plitron transformers, Gravity Base, and everything they could do in 2020.  The SMc Amps sound great and I have no desire to make any other changes.

Having heard several current Class D designs, gan-fet included. They sound fine, but I hear the lack of overtones, decay, body, and depth. They sound good though, I would not bash them, they are very clean and quiet and fast, 1st transients are their strong points, sound comes at you with impact. To me, it gets into what you enjoy, but if, over the many years, you have gained experience and an ear for real sound reproduction, class D would take some getting used to. I do love their lack of weight, so that is tempting for me, any amp over 75 lbs. I am no longer interested in it at my age. 

https://forum.audiogon.com/posts/2795609

Can someone describe how the sound of the Aavik is better? 

Need to listen to the Atma-sphere amps. To date, the best I have heard are the false tube type made in Italy. Cant remember the company name. Still not as good as tradition types to my ears. Most class D I have heard sound pretty pedestrian. 

@phillyb everything you said is what I hear. And it was exactly like that when the popular Nuforce class-d  amps appeared 20 years ago. Then you hear traditional amplification that has ‘realism’ and you notice the weakness.

However there have recently been some ultra high end brands, such as Tidal and Aavik, who now claim to have cracked class-d in sound quality and the reviews seem to concur, so I keep hopes up.

Pickup a used Aavik (Denmark) U-150 Integrated if you can find one......Hook it in to your system...get the one that Huff says has a world class DAC and MC phono amp included........each worth 8K on their own merit...End Game....if you're not blown away send it back....TMR has one around $8500.

They are often described as having a more natural sound due to their minimal feedback requirements, which helps avoid harshness

@mapman This bit is nonsense, just so you know. The use of GaNFETs has nothing to do with how much feedback is or isn't used. 

Capable of driving difficult loads, such as planar or electrostatic speakers,

This bit is only true if the amp employs a fair bit of feedback. Otherwise it can be load variant.

GanFET technology offers several advantages over traditional Class D amplifiers, particularly in sound quality and efficiency.

The main advantages are lower parasitic noise due to reduced inductances, and a lower turn on resistance resulting in less heat.

I've been using a Classe CA-D200 class D amp for years.  I don't know which "type" it is, but I've been very happy with it in my main system.  I admit I haven't auditioned anything else in a long long time (I was using a B&K amp before the Classe) but I don't feel as though I'm "missing" anything. After visiting what seemed like 200 audio systems during AXPONA I was delighted to discover my system sounds pretty darned good in comparison to a lot of the megabuck systems I heard (I know, I know, the show systems are set up in less-than-ideal acoustic spaces). I probably should bring home a big old A/B beast to compare, but I'm experiencing a mix of laziness/satisfaction that makes it difficult to take that first step. My son and I listened to Paranoid Eyes from PF's The Final Cut (2016 vinyl reissue) on Saturday and the combination of microdetails, midrange sweetness (piano) and low frequency slam were breathtaking. 

@atmasphere thanks for clarifying.  

I love the sound of my Technics SU-G700M2, which uses GaN FET.
Takes me to la-la land every time.

All the best,
Nonoise

you know what - my peachtree gan amp sounds lucious, pristine, weighty, pure, etc - but what it doesn't have - is the ability to be musical and inviting

its "I'll settle for this gorgeous sound of my class d amp - but ill sacrifice musicality"

Listen to a more conventional amplifier and tell me its not musical - its a little sloppy - but its not robotic

My Peachtree Gan 1 is as MUSICAL as any of my class A or class AB amps....It's a tremendous value.....Peachtree has a return policy. Try it.  Saying that it's not musical is just not factual. .  I feel it's actually MORE musical than my similarly priced Belles Aria which is a highly regarded amp in the $2500 range.You like ROCK.....It would be a perfect amp for you. Everyone has an opinion......

The company that created the NCore amplifiers, Hypex, is now a full 5 generations beyond NCore.  Their latest circuitry is call Trajectum.  This advanced technology is used in Mola Mola amplifiers.  The performance of these amplifiers is a significant step forward in sound quality.  They have the speed and dynamics one expects, but are also wonderfully 3D, have body and presence, and beautifully smooth high frequencies.  They are found in Mola Mola's Kula integrated amps, their Perca stereo amps, and the forthcoming Ossetra mono amps.

Orchard Audio has terrific Gan amps, I think the tech has really evolved into something quite remarkable. 

I can't say enough good things about the Atma-Sphere GaNFET Class D monoblocks, which have been in my system for the past four months. They have been a big part of the transformation of my listening experience.

The A-S monos replaced a pair of excellent PS Audio M700 class D monoblocks, which used the ICE modules along with some fine-tuning of the output stage to improve the musicality of those amps. For me, the M700s had earlier replaced the classic Pass-designed Adcom 555 stereo class A/B amp, which sounded smooth, but emotionally subdued in comparison to the M700s.

In comparison to the M700 ICE monos, the A-S GaNFET monos sound much more transparent and smooth in the highs and midrange. When paired with the planar-magnetic drivers in my new PS Audio FR10 speakers (acquired in January), the A-S monos have incredible synergy. Their amazing transparency and smoothness make them a perfect match for the low-distortion drivers in the FR10 speakers. This is the sound that is often described as open and transparent without harshness.

The low frequencies are also outstanding with the A-S monos, but they took a bit longer to develop in my evolving audio system. With a recent upgrade in my streaming gear to the Innuos Pulsar streamer, I am now also hearing the deepest and most natural-sounding bass I have ever heard in my home system. (Listen to Joe Morello's opening drum solo on "Take Five" from the album "Morello Standard Time" and you'll know what I'm listening to.)

Anyone who questions the musicality of GaNFET Class D should listen to the Atma-Sphere Class D matched with the right sources and speakers. The realism is amazing!