What are the best GaN Amplifiers available today?

Folks, just so you know, if you are going to be successful with a class D product, one thing it has to do is meet EU Directives for radiation, so it can obtain the CE mark for use in Europe. In the US, you have to meet FCC part 15.

But its more than that. If the class D circuit makes noise, which will be in the form of RF energy due to parasitics in the design, this noise can leak into the AC line as well as being radiated to other components in the system. Both digital and analog gear can be quite sensitive to this sort of noise. It might blot out certain FM stations on your tuner and generate noise on the AM dial. GANFETs in particular are insanely fast and can switch at some amazing speeds. Just before release of our class D we were concerned about the devices running warmer than we thought they ought to- we found that there was a tiny bit of noise coming from the comparator chip, causing the outputs to switch at 60MHz!

When you change out parts in the output filter or elsewhere in the design, the change can result in parasitic noise due to extra inductance that is introduced. An example is the lead inside a capacitor, which can and is a different length depending on the part used.

For this reason the product needs to be tested for RF and AC line radiation. Failing to do this means that the probability of noise introduced through modification is very high!

Any class D designer will tell you this.

They will also tell you that any such modifications voids the warranty.

@ricevs 's comment about distortion is simply false and this has been known for 90 years in the audio world 😀 (ref.: see Radiotron Designer's Handbook. 3rd edition). Perhaps he could get out there and show us all how its done by designing and building his own design from the ground up.

Ralph,  

I have been modding class d amps since 2005.  No one has ever heard birdies or AM signals or whatever.  I can clearly see the harmonics on my scope riding on the 400-500K waveform.....What I do does not increase the noise and as I just said, NO one has ever had a problem...........The modified Wima caps I use have super low inductance (5mm long).   The real issue here is that the mods I do work (make the amp sound better and that my customers all agree on this) and it goes against your "philosophy".   You don't believe that fuses, wires, jacks, etc. into infinity make any sonic difference.  Fine, go to ASR and join the bunch there.  But for those of us that listen....we know different.  WE EXPERIENCE TRUTH with our ears. 

I think you should get a 90 year old amp and be done with it....since they knew everything about how something sounds 90 years ago.   Living in the past is not living in the now.  You have to come out of your comfort zone to experience anything new.  What is real can be experienced in the NOW.....it is not a philosophy.   

God forbid we should void our warranty!!!!!  Do you know how many people void the warrantee on their brand new Corvette (etc.) and take it to a speed shop to have 2-300 horsepower added, etc?  Tons of people do this because they want better performance.  These guys will spend $20-30K doing these mods....even more.  My mods do the same for $500!

Back when SACDs first came out I made a comment online that my highly modded $200 Sony CD player made the CD layer sound better than playing the SACD layer on the Sony SCD-1 that I had at the time.  This did not sit well with the editor of Positive Feedback....as he had just said SACD was the next coming.  He was also using a stock SCD-1.  Wellllllllll.....he then discovers a local modder (Richard Kern) and realizes that the modded player sounded way better......then he takes it back to be modded two more times and it keeps getting better.. He actually wrote an article in Positive Feedback called "I don't drive stock"....about his experences with modding.  HE WAS OPEN ENOUGH to listen.......Now he knew I was right about the SCD-1 not being very good stock.

Really snarky to add the usual....."Well, if you are so smart then why don't you build your own thing, from the ground up".  Being a skilled designer and being a skilled tweaker are two different things.  Those few that do both bring some seriously great products to the market.  I have been bugging Clayton at Spatial for years to use better parts, wiring and construction.......Finally.....he is doing what I suggested.......many, many years later......he did learn.....some never learn.....some will take their limited knowledge and experience to the grave.   

May you all learn the magnificence of your own being......You are all amazingly beautiful.....Open your hearts and minds and experience the joy and Love that you are........it has always been here....it will always be here.....this very NOW.  LOVE....yourself and everything......EVERY SECOND.

From what I understand, both Ric and Ralph make significant contributions for audiophiles and music lovers all around. As both engineers and designers, it is healthy to have different viewpoints and approaches. In this case, it seems this disagreement is making the thread go off the rails a bit.

Generalized statements are painful. While Ralph may prioritize noise elimination, is it true that he believes it is the only thing that matters? While Ric focuses on improvements to existing architectures, does it mean he doesn't understand distortion or how to do his job without keeping noise away? As system thinkers, you probably share more than you think, but it's obvious you've lost track of common ground with each other. I hope you regain it, at least to agree to disagree in ways that enable each of you to push each other to make even higher performing components. And hopefully, so you don't spite each other on a public forum.

I vote for both of you to have a 5-day hackathon locked in a room somewhere to land on a design together. I bet great things would happen, that is, unless only one of you would come out of the room alive at the end of it!

The reason I went to Ric for mods was I had my Sony SCD-1 modded 20 years ago the way Ric described in his post (by KERN I think). The change in sound was incredible, especially in the SACD layer. I had that player for over 20 years, and it only died earlier this year. Someone bought it from me for the parts. The warranty was the least of my concerns.

Regarding the Magenepan LRS+ and the GAN400. I had this setup in the past and getting the GAN400 delivered either today or tomorrow for the LRS+. It has a bit of hardness to the top that makes it slightly less than fantastic.

I was not aware that Ric does mods on the GAN400 and that the module is the same as the Voyager 350 GAN. He did the mod on my old Voyager 350 GAN so I may consider getting the GAN400 modded if I plan on keeping it. The warranty on the unit I am getting expired already.

Generalized statements are painful. While Ralph may prioritize noise elimination, is it true that he believes it is the only thing that matters?

@blisshifi Of course not! @ricevs apparently has a lot of misconceptions and is putting words in my mouth, making claims that I never made. My position about distortion has been clear for a long time. I've been building class A triode zero feedback OTLs for over 45 years and in amps like that everything you do makes a difference because the amps lack feedback. This is the same as in SETs, of which most also lack feedback.

Just because something was knowledge 90 years ago, like 2+2=4, does not mean its not true today. What is different now, which simply had to be accepted back then, is we know why our ears respond to distortion the way they do. In his comments, Ric conveys that he has not obtained this as part of his knowledge base. He's got a lot of company in that regard- many solid state amplifier designers don't really care what sort of harmonic spectra their amps make.

But some do and not surprisingly their amps get more regard in the audiophile community where people 'follow their ears'. For one to push exactly that sort of philosophy, which I've no problem with at all, since that very thing has kept me in business, that the reason why is being described as poppycock is really a bit astonishing and ironic. You'd think this would be of paramount importance to one who has built his business model 'following one's ears'!

Obviously not all amps are the same. Those with very high feedback amounts will respond less to things like fuseholders, IEC connectors and the like because they have the ability to reject that which is not like the signal. But amplifiers with little or no feedback are very prone to these influences.

Regardless of how much luck one may have had doing mods, class D amplifiers are quite sensitive to layout problems, stray capacitance and parasitic inductance that other amplifier technologies simply are not. It may be that you don't hear any audible artifact from a modified amplifier, but without testing it you really don't know what's actually going on. That's a fact and no amount of remonstration on Ric's part will change that. Integrity requires that sort of testing for noise be conducted, if one is being paid to make changes.

The simple fact is that audio would not exist as a hobby if engineering did not exist. Nothing that we do in the audio world is magic- there is an engineering correlation to everything we hear. But you have to know how the human hearing perceptual rules work to be able to sort out some of the whys.

I find it amusing that someone is trying to denigrate me by lumping me in with the measurement camp. I'm not part of that; what I've found is that correlation I mentioned. Both the subjectivist camp and the measurement camp hate the idea that you can draw a direct line between what we hear in audio circuits and what we can measure in them. Many audiophiles still live their lives according to the myth that we can hear things we can't measure (which was true in the 1980s) as if somehow measurement technology had not marched into the present the same way that every other tech has improved over the last 35 years! Imagine trying to surf the web on an Apple 2 😁