AGD Audio Mk2 review


This is my review of my AGD Audion Mk2 monoblock power amps. These are Class D amps with Gallium Nitride power MOSFETs.

As those who follow me know, I am a Single Ended Triode tube amp guy since I like high efficiency single driver speakers. I've tried to like solid state power amps and have bought and tried the First Watt F2J and SIT-2 power amps but ultimately selling them as I find that they fall short of my 300B SET amps.

I first tried the AGD Audions when they came out in the Mk1 version. I was very happy. It had great dynamics, better bass extension, smooth, organic and natural sound comparable with my best 300B (and I use late 1930s to 1950s WE 300Bs). Finally I found a solid state amp that I can live with.

Then this year, the new KT88mk2 GanT Tube modules became available from AGD. These boosted the sampling frequency from 400khz to 800khz. Power remains the same at 170w/4ohm or 85w/8ohm. The improvement was quite a bit better in my system. Better separation and soundstage. More air and organic nature to the sound. So much so that these AGD Audions Mk2 are now the primary amps in my systems. I still play with my 300B amps but I  am spending more time with the Audions in my system.

Highly recommended and just wanted to share with others my excitement about these Class D GAN amps. No connection whatsoever with AGD other than a happy customer. They are, in my opinion, game changers.


@ddriveman I have the AGD Grand Vivace's and absolutely love them! I'm not a SET or tube guy for that matter, but they were still game changing amps for me. I have the Andante Pre/Dac which is also  a wonderful piece!

Yes, there are now class D amps that challenge the best tube amps on their own turf!


When are you going to have production of your GaN mono blocks and when will they be added to your website and when will they get a formal review?  How many proto types are out there?  The only comment on the sound seems to be from June of this year on your feedback page.  Is there some other feedback somewhere we can read?  Hoping your amp is a super success......but where is it?  Are you having supply issues like so many?

I will say that my Bel Canto REF501S is one of those class D amps that challenge high quality tubes like my AH Qualiton X200.

I am really enjoying this this Bel Canto system along side the X200.

Class D is here and getting better.

When are you going to have production of your GaN mono blocks and when will they be added to your website and when will they get a formal review? How many proto types are out there? The only comment on the sound seems to be from June of this year on your feedback page. Is there some other feedback somewhere we can read? Hoping your amp is a super success......but where is it? Are you having supply issues like so many?


We completed our first limited production run and are now working on the second. No idea about the review- we’re looking into that now. All the amps in the field are from the first production run. It is tricky getting parts. We had to wait 3 months just to get GaNFETs... when in normal circumstances we’d have had them the next day. Once we can make the amps on a larger scale we’ll be putting up a page on it.


Good news. Maybe you can encourage some of the first production customers to comment online. So far, we know nothing of how it compares to things. I would love to recommend the amp but we need some feedback from owners. I know, I am just impatient.........but GaNs and class D seem such a nice fit and we NEED less expensive, smaller, lighter, more effecient amps that sound great......Hopefully soon, you can crank them out faster.

Happy holidays, everyone.......feel the love.

In response to some of the posts...I would say that Class D amps have arrived for sure but in GaN form.

As for 300B amps, I am very familiar or have owned these: AudioNote Quest and Conquest 300B amps all the way to the silver versions, Border Patrol 300Bs, Sun Audio 300B, Berning 300B Siegfried and newer offsprings (1 own 3 Berning 3ooB SET ZOTL amps), different versions of 91a/300B SET amps including one build by Thorsten Loesch with nano crystalline OPTs, Rest assured that I'm not comparing the AGD to run of the mill Chinese 300B or typical 6SN7/300B amps. I also own a Fi 421a (Don Berger) with Silver Cobalt OPTs. Other 2a3, 71a SET amp and other types of SET amps.

Wow, That‘s qiete a bit of 300b armoury there and lends substantial weight to your view on the Audions. If I might ask: what about timbre and naturalness? It seems obvious that in terms of resolution, attack and decay the Class D amps have a lot to offer. Is there any graininess or harshness typically associated with silicone as typically associated by tube lovers?

@ddriveman ,

Good to know about the AGD amplifiers. And it is even better to read when the owner has a fantastic experience. I wish we had more posters like you who have been here for quite some time and post their experience when they genuinely feel about a product. You have great systems posted, which gives you more creditworthiness (in my eyes). Replacing the SET amp with this GaN amp - wow...that's says a lot about these amp's performance, knowing how faithful SET owners are. One more thing - please do post new system pics. Congratulations and enjoy your music!

Hi antigrunge2 and milpai,

Firstly, need to correct a Fi Audio 421a is by Don Gerber, who unfortunately passed, back in 2017. A true SET genius. Sorely missed.

Don't want to sound like I'm bragging, but another important point is that when I compare the AGD Audion 2 to my 300Bs, it's with the vintage WE300B early 1950's tube. I have in my possession, engraved base WE300B (late 1930-40), early 1950's, late 1950's and 1960's and a couple of 1970-80. Any WE300B that is after 1982 (i.e with a round getter) is not as good and don't have the WE "magic", IMHO.

The thing that impresses most about the Audions is in fact, their timbre and naturalness. It's very good. Put in this way, the mids/highs are better than 300B tubes like Sophia Electric Royal Princess, PS Vanne ACME, EML, Elrog and comparable to Takatsuki 300B (I have all these tubes) in my amps/system. It just loses out slightly on air, in the mids, compared to 1950's WE300B. Nothing can touch the vintage WE300B's in the mids for timbre, naturalness and presence. And that's the reason that I decided to post my review. It's that good. For me, it's a better way to use these Audion's than to go with typical 300B amps up to $10K (the Audions cost $7.5k/pair) And bear in mind that when you throw in good 300B tubes, vintage driver tubes, rectifiers etc, a 300B SET amp can add thousands more $$. Now, I'm not saying the Audions will beat all 300B but it is up there amongst the great ones. Just for the sake of comparison, what other 300B SET amps could be better... maybe the AudioNote Japan Kegons, Wavac EC300B are the ones that come to my mind.

Of course, IMHO and in my system and YMMV etc, etc.

Note that I'm comparing on my Rethm Saadhana V4 speakers, 100dB, 8ohm, Single driver speakers (albeit with integrated subwoofers). No harshness or graininess at all. I do use external Townshend Supertweeters on my Saadhanas, When I use the Audions, I turn the supertweeters off, because you don't need them. With the WE300B amps, a low setting (2 out of 7) on the supertweeters can add a little bit more air and extension at the very top end although sometimes I also turn them off. Depends on the music and my mood.

In summary, GaN Class D, as made by AGD, can compete very well with good 300B SET amps.

Hi ron1264,


What speakers do you use with your AGD Grand Vivace?

I'm also considering the AGD Andante Pre/DAC as a second simpler system

I think I will get to hear these AGD amps next weekend.  Looking forward to it. 



that is high praise, indeed! BTW we seem to have surprisingly similar systems philosophy: I have a Wavac EC300b (EAT or Takatsuki) drive Duevel Bella Luna point source omni-directional horns with Murata super tweeters. I haven‘t had access to vintage WE300bs. Any views on their newest incarnation?

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I have heard the Duvel speakers. So yeah, we have similar taste in sound. Nice that you have the EC300B. You should get yourself some 1950 WE300B. As gor the new stuff, they are not quite there. Check out the PSVanne ACME. These are close yo the 1980's WE300B.

Anything after 1988 are new WE300B and not from the otiginal factory.

@ddriveman I have the Persona 3f's. I do like them a lot, BUT....lately I have the bug to try another speaker.


I have AGD Audions that I use with Joseph Audio Perspectives.  Full disclosure I tried feeding directly from my DAC (Bricasti M30) but did not like as much as having my Rogue RP7 in the chain.  The tube preamp added a little "fullness" to sound.


Hi testrun64,


Do you have the Mk2 version? If not, I highly recommend upgrading which is easy. Just get the new KT88 GanTube form AGD and replace by yourself.

I also like to drive my amps with a preamp because I have a lot of sources, DAC and Phono Preamps.

I have never tried driving the Audions directly from the DAC, The Audions are very transparent so you will surely hear differences between preamps, DAC outputs etc.

I do have the Mk2's.  I may have tried prior to sufficient beak-in.  The amps are keepers.  I'm thinking / hoping the end to my amp chasing.  I love the amps and at this point don't plan to change unless Alberto brings an upgrade to the market. I'm all in to the AGD Audion Class D amps.

I also like the preamp because it offers a little playing around with tube rolling and inputs with / when needed.

By the way, the volume control on the Bricasti M3 is really nice.  The control it offers, the smoothness and speed of its operation via "hands-on" and remote are really nice.  Best I've experienced. 

Just have seen the big review of the AGD Andante

I have the Gran Vivace-- I may have a go with his preamp!!!!!