New Generation Class D - AGD Audion Mkiii upgrade

I have always had a preference for horn-loaded loudspeakers which, whilst typically easy to drive, can be quite revealing (good/bad) of any changes in the system. I am running Avantgarde Duo’s and have until now always preferred valve amplifiers for their mid-range and lack of fatigue.

I have heard a number of Class D amplifiers and one or two have sounded pretty good but a bit lean compared to valves. Tha changed when I purchased a pair of AGD Audion Mkii amplifiers. The Audions have an almost valve-like mid-range but with a wonderfully transparent top end and great sound-staging. It’s always been difficult to get really convincing bass with my Avantgarde’s because if you increase the bass level the low frequencies can sound detached from the glorious mids/highs. This changed with the Audions as the bass is faster, more dynamic and just overall more satisfying.

These compact amplifiers have what appears to be a valve for each amplifier. This ‘valve’ glows red and I rather like the effect. I did think this was a bit of a gimmick at first but it contains a Gallium Nitride MOSFET power stage. However, this ‘GAN-Tube’ means that if an improvement is developed you can just swap the tubes for the new version. That is exactly what I have done as AGD have launched a Mkiii ‘GAN-Tube.

I was extremely happy with my Mkii Audions and wasn’t sure what to expect with the Mkiii tubes. But as audiophiles it’s difficult to resist an upgrade. The new tubes were fitted in under 5 minutes. I’ve found most components need time to warm-up and ‘burn-in’ so wasn’t expecting too much initially. However, it immediately became apparent that, even at very low volume, there was more detail. I pumped up the volume and was astounded by the wider soundstage which extended beyond the speakers and allowed you to pick out instruments and vocals even clearer. This is something that I’ve found difficult to achieve with Avantgarde’s and I didn’t have with my previous OTL amp. Dynamics are a strength with horns and the Audions really produce a ‘live’ sound, quite startling at times. I’m not great at describing all the audiophile things but would just say that these amps make the system sound so enjoyable and exciting to listen to. They are the best by far that I’ve had in my system.

I know some people will have a hesitation over Class D amps (like I did) but I really think this next generation amps like the AGD Audions will become more and more popular once people get the chance to hear them.


@rajugsw Jay said the AGD Audion amps were the best/top two best amps he has heard.  He said he has heard over 300 amps in a “meaningful way”, whatever that means, but that’s how he came to his conclusion. If Jay hasn’t reviewed/heard the Atmasphere class D amps yet, it’s reasonable that he wouldn’t include them in his ranking.  Stereophile will not add any hifi product to their recommended components list if they haven’t reviewed the product yet.  That doesn’t mean all other hifi components are trash. Stereophile prefers to recommend what they have heard.

It’s in the top two best amps that Jay has “heard” thus far.  That could change once he hears the Atmasphere class D offerings.


@agdproduction Your post was spot on!  I don’t understand how people speak negatively about a product or a hifi tweak without trying it for themselves?

"@agdproduction Your post was spot on!  I don’t understand how people speak negatively about a product or a hifi tweak without trying it for themselves?"


Because it's much easier to write about something they know nothing (or very little) about than to take the time and effort to actually listen to a product!

Some people just like to argue.  What are you going to do? I've encouraged my wife to join in on these discussions many times but she says she just prefers to argue with me 🙃

There is a fine line between discussions and arguing...

The love for truth and the values and role of the arguments set the scene...


I cannot argue with my wife in any trivial day to day mundane matter... She is a very wise and intelligent woman and she is never "wrong" really...i dont remember being able to really fault her save on a unique subject, but she was too innocent and honest in a way to imagine such wrong doing possible by the corporate system... Then it is the only times she was wrong in his life for me...It was about the last crisis ...But i will not go further here...

She could had been  be a psychologist or a philosopher, an artist , because she was gifted,  if she was loving cerebral matter more... She is more pragmatic and on the point in any discussion  than everybody i ever meet... Discussion with her are rational and to the point and  with no back intention ( conscious one ) ...She will never discuss here with people about acoustics and gear as i did ... She "argued" with someone perhaps one time in his life on internet about a moral fundamental issue...Never again...

She stay silent ...Most of the times...


I marry her the day i seduced her by lending to her one TOP books in S.-F. after the others after 5 masterpieces she invited me to a coffe and as intended by me to give me back the books ( i was devilish here)... Then i make his university  philosophical essay because she hate writing philosophical essays and she wait too late , and at the end  she was pleased by the final notation she received ...She was interrogated one hour to investigate a book plagiarism case  because the text as it was written for the teacher could not correspond to his level... Because she was more than lazy, i briefed her before the official interrogation,  one hour about it and she passed the inbvestigation in answering the teacher and investigative group of teachers... It was my best notation too at the conclusion ... She received the highest note..😊

i wrote the 25 pages text in two hours, she corrected it and submit it... But she ask me for a short course on the matter... it was about history and consciousness phases manifestations  in a university masters degree..

We marry after ...😉 It was 50 years ago...


Some people just like to argue. What are you going to do? I’ve encouraged my wife to join in on these discussions many times but she says she just prefers to argue with me 🙃

This Audion GD is just a Class D circuit stuffed into a KT88 glass envelope. It has zero relation to a real vacuum tube. A clever marketing ploy! Add some LED's for that tube-like glow and the gullible are smitten and like Jay's Iyagi proclaim it the best sounding amp ever!

Oh gee! We should be thankful the savior has swooped in, as always, and saved the gullible from being duped by the unscrupulous class D manufacturers. Anyone who buys anything made after 1967, with Topping being the only exception, is gullible by definition.