After 50 years, I have finally found my destination amps... AGD Audions!

We've heard your proclamation on several threads now. Congrats on finding your end game amps....over and over again.

Looks like a couple of you guys love the AGDs. I’m curious myself after building/using class D for several years. Hypex UcD, Ncore, newer Purifi’s.

What kind of speakers are you using and how do you source your content.

I use Roon on front end with Qobuz as my streamer. Never been a tube/vinyl guy, so never went down that path. Had plenty of older Levinson, Pass, etc... Class A, so don’t tell me Class D is inferior.

thx

Congratulations. I think it is incredibly gratifying to purse something for this long and to reach the pinnacle at this time in our lives. I think I bought my Marantz 1060 in 1972. I am enjoying my system as well.

The designer, Alberto Guerra, has a long background in integrated circuit development holding 10 patents including those for the MOSFETs used in AGD amps. The galium nitride modules are the only, and patented, GaNs designed specifically for Audio. All other GaNs were designed for battery chargers, radar or lidar, etc.

@mglik While I'm sure the amp is just fine, the above statement isn't correct.


To be clear, Alberto does share a patent on GaNFETs (US8847408B2). And the modules he makes are of course designed for audio. But it appears to me that you've conflated the modules with the GaNFETs themselves, and the latter cannot be specifically designed for audio. This is because class D are switching circuits which have a lot in common with switch mode power supplies and the like. Put another way: there isn't a way that the device can be specialized for an audio switching application where it will not also benefit a switching power supply or battery charger in exactly the same way.

indeed. they look like such a gimmick so i hope the sound is better than that

underwood hifi has a GaN amp coming out, so he's not the only game in town. 

Mbolek
I run an analog only system through Tetra 606 speakers.(91db 6ohms minimal)
My front end is a Woodsong Garrard 301, Triplanar arm, Lyra Atlas SL cartridge and Atma-Sphere MP-1 preamp.

Ralph
Not sure I understand. If Alberto does hold a patent on the GaNFETs, are not his modules then uniquely designed and one of a kind. (other than the “tube” enclosure) Surely this is the case for much or some central part of the design? Are you saying that AGD are not unlike other GaN based amps?

atmasphere06-15-2021 8:01am To be clear, Alberto does share a patent on GaNFETs (US8847408B2). And the modules he makes are of course designed for audio. But it appears to me that you've conflated the modules with the GaNFETs themselves, and the latter cannot be specifically designed for audio. This is because class D are switching circuits which have a lot in common with switch mode power supplies and the like. Put another way: there isn't a way that the device can be specialized for an audio switching application where it will not also benefit a switching power supply or battery charger in exactly the same way.

I believe mglik's information comes from a 6Moons review or maybe direct conversation with Alberto.  From 6Moons quoting Alberto:
"...The device I use was developed very specifically for class
D audio, *not* for power supplies, low-voltage points of load or RF circuits. Hence the key figures of merit for the device were optimized for best performance within specific voltage ranges, frequencies and current..."
and
"...On why nobody else can use his KT88 GaN, it's like with Nelson Pass' proprietary static induction transitor.  Alberto acquired the entire remaining lot..."

Not sure I understand. If Alberto does hold a patent on the GaNFETs, are not his modules then uniquely designed and one of a kind. (other than the “tube” enclosure) Surely this is the case for much or some central part of the design? Are you saying that AGD are not unlike other GaN based amps?

I'm sure the modules are uniquely designed! That to me is really obvious. But at the same time the circuit design is probably very similar to other class D self-oscillating circuits. It would of course differ in how the circuit is laid out and what parts are used. All class D designers are faced with the same circumstances in this regard.

The idea of the output device being designed specifically for audio sounds a bit like hype to me. GaNFETs are desirable for three reasons- the speed of them, they low resistance ON state and the reverse conduction characteristic. While these things benefit class D amps, they also benefit other switching circuits as well.

What parts are used specifically the GaNFET which is patented. As stated, like Nelson Pass and the SITs. Although I don’t believe Nelson has a patent on SITs.

mglik

Nice to read when someone has found something in audio that is truly special especially when it comes to someone with your experience it lends credence to what you say.

I met Alberto at THE SHOW this last weekend, he is a very intelligent man yet humble and in many ways reminds me of Nelson Pass. It only takes a minute or two to realize that they know what they are talking about and are the real deal. I met Nelson decades ago before all of his current fame, back at that time i knew he was someone special, when i met David Wilson in the 70's i got the same vibe the same vibe i got from Alberto this pass weekend.

I too own the AGD Audion's and concur that they are special regardless of class. Spend some time with them in your own system and you will understand.

Spend some time with them in your own system and you will understand.

I think he already does :)

What parts are used specifically the GaNFET which is patented.

A class D self-oscillating amp will have some sort of converter to convert a square wave to a triangle wave. It will have a comparitor IC to compare the triangle wave to the incoming audio. There may be divider networks to deal with offsets in the comparitor, and the also offsets from the outputs of the input buffer (usually some opamps to give the circuit a little more gain and also increase the input impedance).  After the comparitor there may be level switching circuits to put the comparitor output at the right voltage level for the driver circuits. After the comparitor is also where any dead time circuitry will be located. There are a variety of driver devices available- these are used to drive the gates of the GaNFETs without exceeding their range or causing weird oscillations.


Almost all of these parts are available off-the-shelf. Its good that he has a related patent; this is certainly helpful for knowing how to use the devices :) From what I've seen of the specs Alberto clearly knows what he's doing.

mglik

Wonderful! It must be quite relieving to end the Audio journey.
Enjoy the Music!

Happy Listening!

I also have a set of AGD Amps, the Vivace monos. They are the best sounding amps I ever owned. I'm now looking to upgrade to the Grand Vivace, hence why mine are for sale. 

Can’t afford the Gran Vivaces but am pretty sure that the SQ of the Audions is very similar to the upper models. Think they are beyond merely the “sweet spot” in the AGD line. Think the Audions are overachievers. The Vivaces should sound fuller so the Gran Vivaces. But this should be most noticeable on big musical swells. As it is on the Grans on the big organ piece on the “Gran Vivace” YouTube comparison video. Even though only MP4, one can hear that the SQ of the 3 models is, in fact, very, very similar. But the Gran Vivaces sound more dramatic on the big passages. Mostly they offer more than twice the power for those needing it. My speakers are super happy with the Audions 85 watts into 8 ohms.
It has been said that “the smart money goes for the Audions”.

Hey Guys, Ill weigh in on the difference between Grand Vivace and regular or Audion. The place I noticed it the most was when playing at LOW volume the full spectrum of frequency and dynamic stayed coherent and completely balanced. The Gran Vivace uses a totally different output GaN Tube, the others use the identical tube but Vivace has a larger power supply so you can run it harder for more output and a slight fuller texture in the mid. The Gran vivace is a different animal, as it should be It is the sweet spot if we are comparing world class, we can put this one up against Wavac, Gryphon, DartZeel Etc. remember it has a superior technology to Classes A or AB. Those technologies are drying on the vine, especially now that we have class D at world class level. so the Gran Vivace is like putting Bruce Lee in an amp. Its precise and deals a hell of a punch. Even at low volume your woofers will seize the air in the room. Its super cool to hear the full presentation of music at low volume, I am not accustomed to it. Normally the presentation of the music is not full scale until you get the volume up a bit , not loud but say 78-80 dB. Ill bet I hear full scale at 60 dB with Gran Vivace... in addition to this because I can only play so loud in my room and Audion can play to that limit, but the authority at which Gran Vivace operates is simply stunning. We could rock Scintillas. The Gran Vivace is for your big Wilsons, Magico, the giant Focals Von Schweikert and any of those big as a building speakers. but they still have the finesse to sound beautiful in my listening room for instance...

Hope this helps

By the way the patent is for the layout of a MOSFET, and as Ralph pointed out , It makes it better for anything that uses this MOSFET. That being said it does not mean that a MOSFET designed with audio in mind does not kick ass at everything, and in this instance since Alberto bought the full production run this MOSFET will never be used in anything but audio. So it actually is designed to improve audio performance and it also is exclusive to AGD. So nobody will be able to reproduce Albertos sound no matter how adept they are at copying others work.

And to the one guy who said Walter is bringing GaN on .... You’ve got to know that it means about as much as a Formula 1 team saying we have a Citroen Car running rubber on the wheels just like Ferrari. It absolutely blows my mind that some people can think like this .. Mark Shifter told me he would send me one of these $2500 gems to listen to but no cigar yet and Im not going to ask at this point.Ive got other things to concentrate on , but just like anything all class A is not equal, just like all GaN Class D is not even close to equal. In my experience Ive crushed Merril GaN sound quality with every user that buys AGD. Its unanimous, AGD clearly sounds better. and his amps cost over double Albertos , My observation and opinion is its also nowhere near the chassis custom build quality of Albertos CAST ALUMINUM chassis. Merril uses common aluminum sheet stock, stacked and screwed on in multiple layers to get any thickness, while the Vivace for instance is more than 1 inch thick, solid with no seams. Its a whole different level. Its easy to see where the actual value is, no more of the HiFi BS price level. AGD does not play games he means business. I for one want to see the result if we offer an honest strong value with high performance will audiophiles be able to recognize it and have no hesitation paying retail price, or will they have permanent damage from the way HiFi is normally sold without integrity and fake discounted. I stand against the old way of stroking a customer by high price/ low price selling. its a fake out so when you pay 50% off, its actually the full MSRP manipulated up for purpose of getting people to spend compulsively. I dont support it. So No, other GaN is not the same nor close to Albertos product for that matter...

Happy listening !

OCD HiFi Mikey

remember it has a superior technology to Classes A or AB. Those technologies are drying on the vine, especially now that we have class D at world class level

Lol

Yes, as much as they'd love to maintain their new persona, inevitably the facade begins to crumble. This is nothing compared to one on another thread he deleted.

As far as I can see, skypunk's a dedicated tube integrated enthusiast: Pathos Classic One Mk. III --> Raven Audio Blackhawk --> Audio Hungary Qualiton X200.

Yes, indeed.
Just a matter of time...
mglik, I think it's terrific that you have found them to be such wonderful sounding amps. Enjoy!

Stay close to any sounds that make you glad you are alive.

No matter what topology when listening to those sounds.


 

Not biting on your BS.

I own a Class D amp. Listening to it now out back watching Doves enjoy getting a drink from our pool.
I also have reached out to AGD and I am willing to buy their equipment and then pass judgement. Unlike others here. Maybe you included.

What I was laughing at was the ridicules statement that:

Classes A or AB. Those technologies are drying on the vine, especially now that we have class D at world class level

Poor clown its dying on the vine but yet they are not.

Please enjoy your evening as I will.

Ah, I see my mistake as I incorrectly thought you made that statement.
Never mind.

Whatever.

@earlyflynn if you cant see that Class A is dying youre not watching. I dont mean in our eyes, I mean in ability to buy the legacy components from which to build the amps. The devices to make old school amps is dwindling down and they are obsoleting them. There is no demand except for HiFi, so there is no demand. The generations under me (with a few exceptions im sure)  have no interest in heavy and hot and huge, its an embarrassment to them. Class A is a blatant waste of energy and these days its seen as gross and not applauded except for our little hobby. I own several Class A amps and am not willing to let them go at this point regardless of the aforementioned. Truth is production of Class A amplifiers will most likely be buried in 10 years. If things go the way they have been, expect Class A amps to have an energy waster tax attached to them. And I know its a hard pill to swallow but Class D is finally at world class level. I did not like it either. Im a class D hater. But Im honest and I can not argue this one out . 

All the best ...

@mikepowellaudio reading comprehension is an issue for you all. I am not a class D hater. Every month there are new class A and AB integrated’s, power and mono blocks hitting the market. 
https://parttimeaudiophile.com/2021/07/09/audio-by-van-alstine-dva-m225-monoblock-amplifiers-review/

We will see in 10 years as for your energy waster tax that will add what $4.00 to the price of a class a product. It will fail just as the Gas Guzzler Tax of 1978 did. Consumers speak with their wallets and Suburbans, Tahoe’s and Pickup Truck reign supreme in sales and all are taxed under that statute.

At the end of the day the consumer tells the manufacturer what to build and sell.

Also I have class D equipment in my house as well as A and AB equipment.

There is no argument and supply chain will recover and the market will make what the consumer wants. 

I was going to post this on the other Class D thread but that has Died On The Vine…

This silly argument reminds me of the Motorcycle Brand Wars in the 80’s and 90’s and kind of still lives on today by a few hard core HD riders. 
I was at a track day at the Hasslet MS Ranch in Oklahoma and I rolled out my latest piece of Italian machinery an Aprilia RSV1000SP a Factory Superbike. One of my customers was there with  4 year old Honda CBR600 and looked at my machine, he just said WOW and all I have is this little Honda. I was in the MC business as a parts supplier at the time and always had the latest gadgets in my shop. 
So we went out for a couple of sessions and got our timing sheets. The next session came up and I gave the kid the Aprilia to ride for that session. I then rolled out a 10 year old Honda RVF400 I bought in Canada (never was sold in US Market) I went out on the track and and lapped this kid twice on the latest gadgetry from Naoli Italy on a 10 year old Honda that had not been service in 4 years other than rubber and oil. 
We came back in got our timing sheets and the kid was slacked jawed his times were slower. I looked at him and said “You have have apple before you can polish it”. I told the kid it only matters that you ride and not what you ride. 

I think this relates and I am sure many will not get it.

Listen to what topology you like ABCDZRF, if it works for you then great I am happy for you. Bottom line for me is it’s about the Music (the ride) not the vehicle you use.

@mglik I am so happy for you and I am giving the AGD’s a test ride.

Many of you will twist this post all around and come at me with your agenda. Well enjoy your ride cause I going to get my deceased sons Triumph Speed Triple out and ride around the lake today it was his favorite place to ride.  
Let the twisting begin.

The ears have it. 

Have no idea what you are moaning about @thecarpathian. 
I have directed nothing at or about you.
Please let it go…..

@thecarpatian, I hold no animosity towards you.

And frankly have zero feelings for you either way.

Have a good evening. 

I also have reached out to AGD and I am willing to buy their equipment and then pass judgement. Unlike others here. Maybe you included.

Looking forward to hearing your report, once installed in your system.

Will be while, traveling a lot with work.

Jumping on a plane now for Amarillo to spend a few days with DoE folks. 

Just purchased the Vivace. Truly loving this amplifier and appreciating that it is Class D and so good based on the bad rep Class D has had in the past. I am coming from a decent pair of tube monoblocks (Opera-Consance Cyber 800SE) and the Vivace hasn't lost the tube magic those non SET amplifiers brought out and appreciated with those monoblocks. The Vivace has added so much more to the music that I just cannot compare the two. Again the tubes were a good pair of amplifiers that resided in my systems for years, but yes there are better tube amplifiers at a much higher price and if you are thinking tube magic you think SET not my amplifiers so my comparison is a limited one when comparing the Vivace to tube magic. I have only owned the Vivace for a couple days and still adjusting to all the improvements and know that over time like all things areas of improvement will likely become apparent so I am glad it is modular and there is an upgrade pathway open to me because I am sold on Alberto's designs. The one area that I may, not sure yet, might like to be a bit stronger is in the very low level listening levels. For this reason I was happy to hear that the next step up in the product line seems to have addressed this potential weak spot. Again I cannot say it is a weak spot with authority, because I do not have enough time to declare such a statement as fact. No matter this amplifier is so good that even if the lower volume does not match the higher volume I do not care. I have not heard an amplifier in my system create such realism and magic and when I say lower volume levels there hardly is any amplifier I have heard that matches the excitement that moderate to loud level listening brings, so maybe I should not refer to it as a "weak" spot, but just stress that at normal to higher levels of listening this amplifier is in the upper tier of amplifiers and maybe even in a class of its own for its price point.

First Class  axo0oxa -- I recvd my Gran Vivace yesterday!! Was up damn near all eve. I also have the regular Vivace- Have had that for a few months and just had to try the GV.  Vivace = 911  Gran Vivace = 911 Turbo -- It's that simple--- Not sure what I will do with the original pair?!?!!?  ENJOY==

Congratulations on your upgrade and it is wonderful to hear that it is that easy. I am curious about low volume listening and I mean kind of take a nap or read a book low level listening. Is it indeed much more dynamic at very low listening levels than the standard Vivace module?

Yes sir-- I'm on about 60db or less (quiet for me) and everything is there!! Thats with the Tetra 305 or Proac D2 or Spatial M3 Triodes or pick a Spendor classic 1,2 or 3-- have them all -- I'm done with amps until Al comes up with something down the road that could better the GV (don't see how). Then again I'm scared to change a thing.  I will put his Andante Pre up against my Levinson 526 soon. Who knew it could get this good-=-=

I’m late to add to this thread but I’ve posted elsewhere about my reviews on AGD Audion. I’m an early adopter and started with the Mark 1 and upgraded to the Mk 2, which brought significant improvements. If you look at my profile and systems in audiogoN, you will see that I am a devout SET fan. And the AGD Audions are the best SS amps I’ve tried and the only one I am still keeping. I’ve tried First Watt F2J and SIT2. They were bought, stayed a while, but ultimately sold. And I also no longer lust fir the next great SET amp. The Audions AGD Mk w and my custom Berning 300B OTL SET amp. If I want a little more wetness, air, I go with my Berning with 1940’s to early 1950’s WE300B. If I want a little more power and slam, I switch to the Audions. Ultimately, I’m looking yo have a permanent 2nd system for the Audions with lower efficiency speakers compared to my current 100dB Rethm Saadhana V4. Perhaps a Fyne F1-12 if I can afford it or a used TAD CR1. Would appreciate if anyone has tried their AGD amps on the TADs or Fynes.

Thank you Alberto, for a great amp.

Also, I’ve met Alberto in person at recent LA audio show. Such. Nice gentlemen and true audiophile.

@mglik do you still feel the same about the AGD Vivace's? I was lucky to purchase mine in February 2020 and have loved them since.