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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.

rocketiii
bolong
962 posts
 

In agreement on every point.

abd1
203 posts
 

This threads a few years old but it just is so interesting to see how many tube amp fans, even SET fans, love the AGDs. Count me as one too. I’ve been a tube guy since I first heard a tube system 12 years ago. It was one of the 3-4 audiophile epiphany moments since the first time I remember hearing an actual high quality 2-channel system. I’ve probably had at least a dozen tubes since then and another 6-7 solid state amps of all types. Liked to loved most of the tube amps and liked most of the ss amps but never loved one enough to keep it as my main amp over tubes. There’s just a texture, tone and depth to tubes that pulls me in and keeps me listening  I never got with ss. Until now. My main amp is a Line Magnetic LM845 premium. Love that amp for a few reasons but it is a heater. I moved to Scottsdale a bit ago and that amp is just too hot to use here 4-5 months a year. So I’ve been looking for an alternative that doesn’t make me miss my tube amp and doesn’t run hot. I’ve had Coda, LTA, Luxman, First Watt and while they all sounded fantastic and I could’ve been happy with any as the “summer amp.” But I kept hearing about ganfet amps and seeing so many tube amp lovers praise the sound. I also spent a few months with the LSA ganfet amp a couple years ago and it left me with a very positive impression and even some jaw dropping moments with vocal clarity and texture. So I decided to try the AGD Tempo Di Gan which is the entry model. Right away I was impressed with the sound. It has just enough of that tube texture while also having excellent layering, transparency and detail, with slam and dynamics. Since turning it on a few months ago I haven’t felt the need to switch back to the LM and now it’s already 100 here so it might be awhile. That being said I like this amp so much I just purchased a used pair of AGD Duets, which led me to this thread. I’m really looking forward to hearing them in a few days. Speakers are Fyne F502s and Cube Nunephar Mini. Amp sounds amazing with both. 

kerrybh
668 posts
 

I heard the AGD amps paired with Fisher and Fisher speakers at Capitol Audio Fest. I thought the sound was superb. Of course, it’s hard to tell what a specific component adds to a system and I generally give most of the credit to speakers, but those amps certainly weren’t doing anything to detract Hello hey how from the high-quality sound. The designer also gave a great explanation of the technology involved and his implementation of ganfet. I’ve never really considered class D but I think I could be very happy with those amps
 

ghdprentice's avatar
ghdprentice
9,403 posts
 

All might be interested to know the OP moved on to a DarTZeel integrated not that long after starting this. I had his ADGs in my system for a while I thought they were an excellent value although my Audio Research 160 was definitely a better amp. 

bolong
962 posts
 

Impedance Line Attenuator

My Audion 3 amps play very beautifully with the Primaluna EVO 400 tube pre. You have to watch impedance matching though, and maybe especially if your speakers are sensitive horns. I ran this pairing for 6 months without issue, but then it became a clipping issue which was solved with the above attenuator linked rig. I am beginning to think a tweeter driver may been slightly damaged to bring on this issue all of a sudden though I hear no difference in the upper registers. Could also be a mid or bass driver though I hear no distortion there either. I run My Cornwalls pretty hard sometimes.

Recently the two driver tubes were replaced with Apos Ray 12au7's with which I am heartily pleased. Some of the clipping issue may have been due to old NOS tubes giving out.

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