The Audion Mono Amps from AGD Production

Hear Here

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There's hardly a word about this miniscule Class D amplifier in this forum, so I'm wondering if anyone here owns this odd-looking mono amp, or has first hand experience.

It's a cute looking thing that has most of its electronics built into what looks like a vacuum tube - but it isn't!

On another forum, a fellow Avantgarde speaker owner uses these amps to power his £47K Avantgarde Mezzos. At $7500 per pair in this polished finish (or £6800 in standard), it seems pretty good value, judgung by its exceptional reviews.

Any useful observations welcome. Thanks

Details here - https://www.agdproduction.com/static/audion.html

AGD The Audion.jpg
 
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spiritofmusic

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I wonder what Audion Audio, who make ACTUAL tube amps, think about their choice of name.
 
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awsmone

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I have heard these on ocd mikey site

these are very impressive sort of a cross between tube and ss sound but more detail as they are incredibly fast and with that super bass class d is is famous for

they have a much higher switching frequency that other class d

Mikey Did a nice comparison with 845 tubes
 

Hear Here

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I have heard these on ocd mikey site


Mikey Did a nice comparison with 845 tubes

Thanks - any chance of a link to the site you mention? Peter
 

QuadDiffusor

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sbnx

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This amp uses a Gallium Nitride (GaN) transistor as opposed to silicon. This transistor technology is relatively new but you will see much, much more about it. They have super high voltage (600V) capability and power handling. As well as they have a much higher switching speed compared to silicon. What makes them interesting is that it makes a "high" power single ended solid state amplifier viable. Which Is what I believe AGD is doing here.
 

Sablon Audio

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The AGD options certainly look interesting and I love the cheeky way they have put the GaN board inside a KT88 - admirable juxtapositioning!

Having extensively used both hypex ucd and ncore amps, I find class D technology rather interesting albeit hitherto unfulfilled in my experience. That said, I have always appreciated mosfet power and now have a GaN amp on order from Java. Hopefully Blue58 will give it a whirl on his modded AG Duo Omegas and share his considerations here.
 

cjfrbw

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Class D epiphanies seem to occur on a cyclic basis (caveat emptor, try and trust your own ears first?).

The GaN transistors have low capacitance and very high switching speed with nice square waves without over or undershoot, great attributes for switching amps.

I don't know that they have used them in class A or A/B circuits yet, unlike VFETs which also have very high switching speed and have been around since the 70's and also sound great in A/B, class A, albeit at lower powers than class D (Sony TA N88 was one of the first high power Class D commercial amps, all the way back to the late 70's).

http://www.thevintageknob.org/sony-TA-N88B.html

I think Nelson Pass said in passing somebody at UC (Davis??) might be trying to build GaN SITs, but my memory is hazy. Those would be interesting to hear in audio.
 
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awsmone

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Apparently the use of the tube was used as a way to fool the eye into thinking when people walked in it was a tube rather than class D which makes some people switch off ( pun not intended)
what I am not sure of if they are using similar technology to hypex about their feedback, or if this inherently a more linear transistor
certainly the sound is impressive so far which is what counts and one gets the feeling that Class D is maturing as an audio technology
 

Hear Here

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Apparently the use of the tube was used as a way to fool the eye into thinking when people walked in it was a tube rather than class D which makes some people switch off ( pun not intended)
what I am not sure of if they are using similar technology to hypex about their feedback, or if this inherently a more linear transistor
certainly the sound is impressive so far which is what counts and one gets the feeling that Class D is maturing as an audio technology

Thanks for all replies so far. I understand one of the reasons for encasing much of the electronics in a vacuum tube (no vacuum I guess), is that upgrades can easily be achieved. The "tube" in the Audion's big brother is more powerful and (I'm not sure about this) can be used in the smaller Audion. In future other developments could be catered for with a new tube.

However I rather agree that it's a way to suggest this little amp may be tube based. It looks good and I believe this particular Class D technology offers an SET-like sound so perhaps SET owners who crave better bass, less noise and maybe more power (despite our impression that our SETs are already very good), may be attracted to this amp. I certainly am and agree with you that Class D has reached the stage that buying older technology may be misguided. After 2 years experimenting with a dozen amps of all types, I'm currently using Class D in a NAD M32. I want to improve on this and am torn between the "easy" upgrade to the new NAD M33 (with the latest Purifi module), or to get a power amp such as these AGD Audions or possibly the Bakoon 13R to power my Avantgarde speakers. Peter
 

pdubya

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I’m the Avantgarde owner with Audion amps previously mentioned. A few comments:
I have no complaints about what I hear with this speaker/amp combo, but must admit I’m pretty inept at parsing this satisfaction into audiophile terms.

Mike Bovaird, owner of Suncoast Audio/AG dealer/Mezzo owner for several years, tried at least a couple dozen SS amps with the horns. I think the FirstWatt SIT3 ended up his favorite, but the surprising runner-up was the class D MBL Nobles. Of course, overall he preferred tubes ...

My understanding from the Audion designer is that there Is no upgrade path for the smaller monos but the larger models have a more powerful replacement tube option. I believe Srajan has been covering those.
Parker
 
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cjfrbw

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My experience with class D is that they do sound great up to about 600 Hz or so, but above that, they get a little dusty, bland and not very natural sounding. H20 types on Apogee Scintillas sounded OKish, I guess.

I haven't heard everything, though, and technology does advance.

The promotion from the outset years ago was that they were SET killers, which never really applied in reality, except maybe in that stated sub-600 Hz range. That's the kind of hype that produces not just grains of salt, but a pretty large salt cellar.
 

analogsa

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My experience with class D is that they do sound great up to about 600 Hz or so, but above that, they get a little dusty, bland and not very natural sounding.


Hey, you are describing the old class D, with the wretched silicon mosfets. The new ones bring a paradigm shift ;)
 

christoph

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cjfrbw

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I'm part of the Audiophile Beat Generation: beaten down by paradigm shifts and game changers. Every time another one comes along, I feel giddy and a bit woozy in the stomach.
 

Kenc

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I gotta also say that when someone says "Audion" amps I think of the semi-venerable UK valve electronics company that decamped to France. I had their Quattro Premier preamp for number of years...extremely "musical", albeit a bit noisy in my hands.
 

awsmone

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I agree that paradigm shifts are overstated often
from what I have heard of these audion they are very good sounding unlike older class d
the new purifi modules are pretty specular in terms of specs

i guess it the age older dilemma is if technical perfection is associated with desirable sound qualities

on the sterephile blogs I had discussed with JA and HR the concept that recorded sound loses some harmonic content ie is bleached of harmonics, and that controlled harmonic spectrum which doesn’t change with frequency or output, may be sonically desirable
a number of good sound amplifiers appear to have these characteristics
I have recently experimented with adding a DHT tube pre in front of my goldmund amplifiers and found the results very desirable over a passive volume in front of them
at least in my system this seemed to work

Nelson Pass has trodden this role for a long time, and recently discussed second versus third harmonic distortion and how it’s perceived , interesting the reviews of the wonderful xa25 is perceived as very transparent is lower than his previous amps

xa200.8

xa25

i should credit these come from the Stereophile measurement section of both

there transfer functions are somewhat different
interested in anyone who has or has heard both ?
 

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cjfrbw

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I tried reading Srajan’s review of the AGD Audion. It’s one of his most discursive, opaque and baroque yet.

They say that French is the language of diplomacy, because you can gesticulate and talk forever without ever saying anything. That’s kinna how I felt trying to machete my way through the verbiage.

He must do pushups and jumping jacks in between the manic whirling dervish plugging and unplugging the review samples between multiple systems and speakers.

The only way I actually figured out it was supposed to be a favorable review is that he gave it an award at the end. Whew! I did get the ole’ saw about class D crushing SET (again), and, of course, all that clean powah. Lotsa power isn’t to be ignored! And in a cool running and kewl, compact package (or was it merely medium power because it was less than 500watts@8ohms?)!

They already have their Mk I, II, III, IV, V etc. etc lined up with the upgradability of the 'tube' portion containing the GaN array, so the marketing department is fully prepped for the future.

Has the class D train finally arrived? I think I need to unscramble my brain before attempting to listen.
 

the sound of Tao

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I tried reading Srajan’s review of the AGD Audion. It’s one of his most discursive, opaque and baroque yet.

They say that French is the language of diplomacy, because you can gesticulate and talk forever without ever saying anything. That’s kinna how I felt trying to machete my way through the verbiage.

He must do pushups and jumping jacks in between the manic whirling dervish plugging and unplugging the review samples between multiple systems and speakers.

The only way I actually figured out it was supposed to be a favorable review is that he gave it an award at the end. Whew! I did get the ole’ saw about class D crushing SET (again), and, of course, all that clean powah. Lotsa power isn’t to be ignored! And in a cool running and kewl, compact package (or was it merely medium power because it was less than 500watts@8ohms?)!

They already have their Mk I, II, III, IV, V etc. etc lined up with the upgradability of the 'tube' portion containing the GaN array, so the marketing department is fully prepped for the future.

Has the class D train finally arrived? I think I need to unscramble my brain before attempting to listen.
I’ve always thought Srajan’s writing was a bit too closely touched by the hyper-threading multiverse vortex out of a postmodern verbiage mixmaster myself... however I must defer...am definitely preferring your take on it, much more eloquent. You’ve just made it a (perhaps not) must read for me.

I get brain hurt concentrating on all the whirling anarchic thought deflections when wading through his text unfortunately. It’s like riding through a live demonstration of string theory. Also I must admit I am never quite sure which product exactly he is talking about as he whips never heard of references in and out of most every other paragraph. There is the odd gem in there at times but it takes very concentrated effort to uncover.
 
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