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.


@dseltz I'm sure they are.  Ralph has certainly been successful for a long time and probably has a great plan in place.  I just love the idea of not having to send the amps back for updates and having the updates essentially delivered to you.

I am a fan of the AS Class D (I own a set)

I have not heard the AGD so can not comment on the sound

I believe BOTH companies designed a GanFET Module from the ground up for their own purposes. Building an amp with the sound characteristics that they felt was best.

Although an easy, at home upgrade is awesome, so is an upgrade that includes new Caps, resistors, and other parts I am not comfortable doing myself. Again, probably an individual preference so we should not be insulting one another over which one they prefer.

@arafiq - I, too, would be willing to do an at home audition between the two (if someone wants to let me audition their AGD lol


I can't afford Ralph's amps, much as I'd love to get one, or the AGD amps, but I have my eye on the March Audio amps. Owners seem to love them. 


You can score used LSA Voyager 350 GaN amp for ~ $1800, have it shipped to Ric Schultz (Tweak Audio) for mods and be beyond happy; You might even find a modded one ~$2500