AGD Duet Monoblock Amps BLOW MY MIND! Desert Island Amps!

My Desert Island Amps. AGD Duets BLOW MY MIND!

By Steve Huff

Over the past several weeks I have been listening to TWO sets of monoblock amps that are very small, very light, have a drool worthy design as well as a sound that I have never heard from any amp, ever. It’s not that these amps are “better” than all I have heard so far in my audio lifetime (37 years of audio, 55 years old), rather they are just several levels up in the experience that they bring to my listening room. Several levels up from my previous favorites in amplification. Different from the others I have heard. 

My Video Review of the AGD Duet and Audion MKIII

Sure, that statement my sound like hype but in this case these pieces I have here from AGD deserve all of the hype they can get, and they deserve it for so many reasons. I will explain these reasons within this review clearly and plainly. I will talk about why these amps and the tech within them are (or should be) the future of premium music reproduction.

Spoiler alert: These AGD Duet amps unseated my previous 4+ year reference monoblock amps that cost much more, weigh much more, run much hotter and are huge. The Alto II Preamp unseated my 3+ year long reference pre, which cost almost 2X that of the Alto II. While I have not used my separates much over the last 2 years due to weight, heat and some buzzing noises I placed them back in during this review period and yep, the AGD easily bested them in all areas and it wasn’t even close.

I have had the AGD Audion MKIII and the AGD Duet Mono Amps in house for several weeks now. I have had the AGD Alto MKII pre-amp for less but will give my early thoughts on it as well within this review. As soon as I saw and heard them I knew these were created with a strong passion from a music lover rather than a head of a corp who calls the shots. 

Yes these come with gloves as the polished finish will be a fingerprint magnet. I wore them as to not smudge them up before filming the video review. These user upgradeable amps also come with a polishing cloth and audiophile power cords. 

It is 2024 and yes my friends, there is certainly new tech in the audio amplifier world and this small company called AGD is proving this again and again. I heard of AGD a couple of years ago when some were raving about the brands very unique and beautifully designed Audion mono blocks. These amps surely looked cool with a big KT88 style glass tube sitting on the top of each amp and the brands very old school logo carved out in red. What made these special though was much more than the glass tube design.

Oh and to be clear this AGD is NOT “Audio Group Denmark” which has the same initials. Rather, this AGD is the brainchild of Alberto Guerra, hence the “AG”. I can assume, maybe that AGD stands for “Alberto Guerra Designs”, but I could be wrong (and most likely am). So before we get rolling on the Duet review let me first talk a bit about the Audion MKIII from AGD. 

The Audion MKIII is one unique mono amp but not only in the looks. These sound even better than they look, and then some. The brands DUET amps sound even more refined. 

Yes, you do see a tube here but this is not a tube in the traditional sense. I am sure most of you reading already know about these tubes and what they do but I am certain some of you may not.

This design with the Audion amps is about as unique as it gets in high end audio. I have seen some unique pieces of HiFi over the years and these sit up there with the coolest designs I have experienced. The tube here does not house the parts of a tube but instead it houses the actual amplifier, which uses GaN technology that was worked on, created by and brought forth by the amps creator and company owner Alberto Guerra. In fact, this amps tech is quite different from every other GaN (Gallium Nitride) amp made today. This one doesn’t use Purify modules, nor Hypex. It also does not use what Aavik uses in their class D designs, Pascal modules. Let’s face it, even with the advancements in Class D audio, and there have been huge strides over the last few years…some still have very little soul and only a very slight few can convey the emotion within music.

These class D GaN modules in the AGD amps are said to be made JUST FOR AUDIO by AGD and you can tell from the first musical note that emerges from your speakers that this is indeed the case. These are instruments of the highest caliber for recreating the musical performance in your space and yes indeed these ARE instruments. Just as I consider some of my speakers instruments, I feel the same about AGD amps after spending considerable time with them.

As I write these words now I am listening to the Duet amps with the AGD Alto II preamp hooked up to some lovely Pearl Sibelius speakers. The sound is ethereal as I listen to a track by Brique a Braq called “Le 4 novembre”. The Piano is haunting here and the notes just do not just hang in the air, they float outwards towards my seat. Such an amazing experience even when streaming from Spotify, which I am. The HiFi Rose RS130 and this DAC inside of the Alto MKII can really make Spotify sound quite stunning and at times, bests Tidal or Qobuz with the same tracks. I also stream Tidal and Qobuz and even have ROON. Even so, sometimes Spotify with this setup gives me more chills than using ROON and I am not sure why but it does. The RS130 is one of only two streamers I have had that does this with Spotify (Lumin U2 as well).

BTW, the Alto MKII also has a streamer built in and works with ROON as well as Tidal and Qobuz. It’s does Airplay as well and it sounds very good, maybe 90% of the 130 Streamer, which is a $5400 box all by itself.

The AGD Alto MKII is one of the brands pre-amps. This one has a custom, built in house R2R DAC, Streamer, as well as a killer MC and MM phono stage. A perfect mate to the AGD amps. Simply gorgeous in every way. The attention to detail impressed me as I do not normally see experience these things, to this level. 

CLASS D IS MIND BLOWING GOOD HERE, FORGET WHAT YOU THINK YOU KNOW ABOUT CLASS D!

For me this “AGD sound” has more soul and life than anything I have heard from Class A, Class A/B or any solid state design. Notice I said “For Me”. I still adore great Class A designs as they also have something about them with the sound that gets me. Even so, the AGD’s sound is just as beautiful and rich as the absolute best I have heard (for me), no matter the cost. Sure, others get close and I adore some Class A designs but for all out sound, artistic design and the tech…well, these are remarkable.

There are many doing Class D these days and my oh my has it improved so much since the early days. Even so, there are many of you out there who may have tried a class D amp back many years ago or even today and were let down. Maybe you bought an affordable Class D and it sounded dull and flat. Maybe it was harsh or gave you fatigue after a couple of hours. Maybe it thrilled you at first but then over time you noticed the lack of life and soul within the music. Maybe it was too smooth and boring.

Those early basic class D designs (and some current designs under $1k) were and are truly a mess IMO and I personally am/was not a fan. They could sound grey and thin or maybe not bring much of a foundation to the music. As for soul, forget about it. There were no early class D amps that had any kind of soul or heart touching qualities IMO. I had one of the first Class D amps/speakers from Bang and Olufsen well over 20 years ago now I believe. It was tough to listen to. 

Peachtree came out with the GaN 1 not so long ago for $1500. It has only one input, a digital COAX for use with a streamer. This is all one needs for a streaming setup, just add speakers. No DAC needed. I heard the Peachtree and now have a competitor of theirs in the house from VTV (which I reviewed HERE). They sound very good, very nice and very powerful. With that said, they do not have the soul of the AGD amps. Also, they do not have the price tag of the AGD either, so there is that. 

Not so long ago Peachtree came out with the GaN 1 (above), a GaN class D amp with speaker outs and one digital input, for your streamer. I heard this amp and also have one in house now that is similar from another USA company named VTV. Both of these GaN amps are very nice, sound lovely and are perfect for a simple and affordable one source solution. With that said, the AGD amps seem to be on another level compared to those two in regards to design and yes, even the sound is more refined and beautiful with the AGD set.

I get more life, more body, more organic sound from the AGD amps though stepping up to AGD will deplete the bank account a lot faster than these $1500 amps. There should not be any comparison but the simple GaN amps do sound amazing for the price.

So yes, class D amplification used to sound thin, harsh, dry, and was 100% without soul (in my opinion) but it has come a long way, at least with some brands implementations and creations.

These days it seems that some manufactures are upping the game with Class D and recent amps I have heard with this tech have been phenomenal. Amps like the Maria from Daniel Hertz had such an analog sound with rich bass, open mids and a warm smooth top that remained extended. I thought that would be the best I have heard in Class D but the Maria really was designed to be paired with the brands own speakers, as the Hertz amps are “tuned” to each speaker by Hertz and may not play as well with others.

Hear the Duet with Borresen X2

The flat tuned Maria (when tuned flat I should say) was very flat so I loved it most when paired with the Ambers using the Amber tuning. When flat it could not compare to the sound I am getting from these AGD amps. I would still own the Maria if it didn’t develop an electrical issue. I had to get a refund of that piece as Hertz had no idea what it was happening…to only me. We tried two and somehow both had an issue with static electricity in my home. So the Maria is no longer here for that reason and that reason only.

Going back to AGD, after experiencing what these AGD amps did for all of the speakers I have here (seven sets as of right now) I realized that these amps are very special to me for more than a few reasons. I realized that, for me, they sit above almost all other amplifiers I have heard when it comes to the qualities of what makes music reproduction stir the soul.

Organic, open, fluid, big sound, some warmth, world class detail but with body, holographic imaging and real and live sounding is right up my alley. I love when a system can really connect and suck me in for hours on end. Music, for me, feeds the soul and not all systems or audio products can do this for me. Only some have in the past, a select few. The AGD amps seem to be able to do this with ease for me as they deliver all of the qualities I seek when it comes to sound reproduction.

This tube houses the GaN amp module and when a new version is available, just buy the new “tube” and you now have an all new amp. 

These Audion MKIII’s that I have here have seduced me with their rich luscious sound that is very detailed and open but comes with a massive soundstage that has depth, layers and texture within the mids and bass. There is body to the sound and somehow these amps do this without muddying up the mids or lower mids. This is a sound I have never heard before, even when I had $30k-$40k+ pre and amps. This AGD sound is way above my previous reference mono block benchmark and I am excited that I was able to discover this brand and hear for myself what all of the rave was about.

But it does get even better than the AGD Audion MKIII for a little more. 

Enter the AGD Duets.

I am so happy I was able to hear both sets of amps, the Audion MKIII and the Duets. It showed me what I would get for the extra $4k that the Duets cost and also showed me that this company is not a one trick pony. The Duet amps bring a bit of a different (yet very similar) vibe vs the Audion amps.

For the days after both of these amps arrived I was giddy, happy and truly blown away. My wife noticed it and asked me what I was so happy about. I tried to explain to her the “why” but she didn’t get it as she doesn’t care to know much about tech specs, she just knows when she likes how the system sounds. Yea, she loves listening with me and she does hear the differences in the gear.

The black Duet look a bit different from the polished versions on the AGD website. More subdued of course and the black will be easy to keep clean. 

The Duets vs The Audion MKIII

This whole thing started when I contacted AGD and asked if they could send me a set of their Audion MKIII amps for me to evaluate and possibly review. Since I only review gear I love, well…I made sure Alberto knew this. I would check them out and if I loved them I would review them and possibly buy a set as I am looking for new mono amps (lighter, smaller, cooler running). I admit, I have been searching for a new amp for a couple of years and it has not been easy to find the “one” that really satisfied my wants in an amp. I had high hopes for these AGD amps as something was pulling me to them.

Alberto called me and told me he would like to send me a set of the Audion MKIII’s in black but also wanted me to hear his latest creation, the Duets. He then explained to me what the difference was between the two besides the extra $3500 or so that they cost . He went on to tell me how many loved the Audion sound, but some didn’t like the Tube up top because it was not really a tube in the traditional sense. He explained how the tube was placed there for valid reasons, that are well, very valid.

The top view of the Alto MKII Pre Amp from AGD. Near perfection for me in a pre. I was told the remote that was sent (which is cheap and plastic) is not the remote that normally ships with the Alto II. Alberto said he was all out of the metal remote and would ship me one as soon as he gets them back in (He Did). 

With the Audion model, by placing the amp module in the tube (Audion MKIII), when a new version comes out one can just buy the new tube at a MUCH lower cost than buying a new set of amps. One can keep the various “tubes” and have different versions of the amp. To upgrade, remove the tube, insert new tube and you have an all new upgraded amp. HOW SMART IS THIS! A new tube costs around $1500. With AGD’s Audion amps, one no longer has to sell the old amp at a loss to get the new one. Just buy the new tube and you are set. I know of a guy who has all three “tubes” and he can go back to the old sound or the new sound at any time.

This is so much better than say “Company B” who puts out a $10k amp and then 1-2 years later has a MKII for $11k, telling you how much better the II is. You then sell your MKI, lost a few grand and put more of your hard earned cash into the new amp only to find in the end, it’s just a bit different but not really “better”. I’d much rather buy a new tube for $1500 and have my new amp, losing nothing but gaining the new sound.

I feel those who are speaking out against this “tube” design have an agenda. Maybe they make some big black heavy $10k+ amps and do not like this kind of competition. In reality it’s 100% genius and awesome and it looks spectacular as well. It’s about time someone did something different to shake up the audio industry which cam sometimes seem stuck in 1978 with big ugly black boxes using the same old tech from 1975.

These Duets are the polished versions. Gorgeous!

So the tube thing is great but for me, this is only one reason why these amps are end game.

The design is also quite nice on the Audion MKIII and I personally LOVE the way the “tube” looks as there are also nice LED’s there to light it up at night. I feel the design is one of the coolest I have experienced. It’s also not overdone or gaudy, looks classy, vintage and as vibe filled as it gets. While these were in my system I also received many compliments on the looks. Everyone loved the vibe. I could care less that it appears as a tube amp. All that matters to me is that it looks cool and sounds sublime.

The black Audion MKIII next to the black Duet

The Duets took away the tube and placed the module inside like a traditional amp. The Duet case is also slightly larger than the Audion but not by much. Also, the Duet can still be upgraded by buying the new module but the module goes inside of the amp rather than in a tube. Either way, the Duet is also upgradable by the user (so I am told) by opening the case and inserting the new piece. The Duets do look slightly cooler in the slightly larger casing and while there is no tube, they still have a very cool retro vibe with the way they are assembled and designed. I only prefer the polished versions as they remind me of some kind of 1950’s product with the shiny look and big red glowing acrylic standby button.

Turns out the Duets are improved over the Audions as they use a high end Class D GaN module for the power supply as well. The Audion does not. See, most class D modules were made for power supplies and some amps that use Class D for sound are using these types of “power supply” modules for audio. The AGD amps do NOT use these types of modules but rather have created custom Class D Gallium Nitride modules that are made JUST FOR AUDIO (and just for AGD amps) and let me tell you, this makes a huge difference when it comes to sound. These modules made by AGD are not “off the shelf” but only used within AGD amps so you will not see these modules anywhere else, or in ay other amp.

So the Duets have this upgrade to the power supply and we all know that the power supply can truly affect the sound of an amp or any piece of HiFi. The Duets have a cleaner sound yet they do not lose the overall character of the AGD sound. They are more refined, and even a bit fuller down below, in the deep bass regions.

The Duets also look even cooler than the Audion’s (to me) but I did not think so at first. They grew on me but the casing is nicer, looks very old school with the metal plates, visible screws and the best part of all in the design is the front button which is large and see though. It shows the AGD logo and when on they glow RED. This looks so awesome in person and especially at night when listening at low volumes. After some time I grew to enjoy the design of the Duets more than the Audion. The button can be pressed and the light goes off without any sound or clicks, and the amp goes to sleep. Press again, it’s on in an instant without any clicks, pops or noise. No static electricity issues either ; )

These two amps do sound different from each other so I will do my best here to explain those differences.

Before I get to the sound let me talk about 13 reasons why the Duet are now my end game desert island mono block amps and replaced my five year mono class A reference. If within budget I would choose these over ANY other mono amps on the market today (unless I had the cash to move up the AGD line). Here is why…

1. They are small and light. No more 100lb boxes to lug around. There is no Compromise made anywhere in regards to sound due to this.
2. They are completely silent, as in medical grade silence. Never did they hum or buzz.
3. They are powerful for their size and seem to have an ability to power anything with ease due to the way they are designed.
4. The design is as cool as it gets for these eyes, something to be proud to own.
5. They are fast as lightning and deliver everything in the recording with precision, body, extension, warmth and fluidity.
6. They do not get hot. The Duets run warm, and the Audions run slightly warm. No class A heat here.
7. They cost pennies to run as they are extremely efficient. No more jacked up electric bills. 95% of the energy gets converted to sound vs 50% of a typical Class A Design.
8. They sound better than just about any amp I have ever heard for my tastes. No matter the price or class, but this is just my opinion.
9. They ship in a pelican style flight case and come with two very nice audiophile  power cords made for audio. Nice.
10. They are fully upgradable by the customer just like the Audion! Meaning, when a new model comes out to improve the sound, we can buy and upgrade ourselves. AGD can do this for you as well if you send them in.
11. The company and owner are very easy to talk to and work with, top notch nice guy. Made in the USA.
12. They are not “cheap” but nothing truly special ever is. These cost much less than some mega amps that do not sound as good. There is a huge pride of ownership here, possibly the best ever in this regard.
13. There really is something truly special about these products and I can tell they were made from passion. No one would create these things if passion for music was not involved. They sit at a level above most high end gear I have experienced, even gear costing 2-3X the price.

The speaker you see here is the Pearl Sibelius. The AGD Audion MKIII and Duet sounds heavenly with these single driver speakers. So intimate. So fresh. So real. So much magic. The Duet amps bring more immediacy and snap vs the slightly more euphoric nature of the Audion but I have to go with the Duets here due to the warmth in the Sibelius mids. The music just flows through the air with these speakers. Lovely. 

SOUND

When the amps arrived I wanted to hear them cold, new and fresh out of the box. It took only an hour or so for these amps to blossom and show me what was to come after more burn in. Our ears also get used to the new sound after an hour or so.

I have a few sets of speakers here now that I tested the amps with. 

I have a set of Borresen X2’s (a new added reference speaker here), Triangle 40th Duetto’s (my bookshelf reference), the Galion Voyager TL’s, my Closer Acoustics OGY and BOB (my main reference) and a pair of speakers from Pearl Acoustics, the Sibelius, which is a one driver speaker sans crossover (I do not own them, in for review. Can’t afford to add them or I would). Soon I will have the Qualio IQ Ultra in as well and I can not wait to try them with the Duets. I will add an update here when I get some listening time with them.

I started with the Audion MKIII.

When I started listening to the MKIII’s I was instantly enamored as I knew right then that these were going to be something very different and very special. The sound was immediately like nothing I heave heard from any solid state amp, regardless of cost, pedigree or class. What I mean is, these amps were sounding as good as the finest I have heard but with their own special character. Voices were solidified and separated from the mix but so was every instrument within the mix. These sounded amazing, with remarkable rendition of space and reverb.

The Alto II Pre

I was hearing the most beautiful sound stage I have ever heard in my 13X18 space. Running speakers from Triangle, the 4oth Magellan Duettos, these amps took these speakers several levels up from what I was hearing from them when other amps were powering them. The sound was divine, surreal, beautiful, honest, rich, layered and haunting at times. Listening to Brique a Braq on shuffle via Tidal was quite the experience. In fact if you have a system set up for critical listening give the album “Circue Noir” a listen. Dim the lights, sit back and enjoy the journey. 

With Borresen X2’s the sound was larger than life, realistic and live sounding though much more meatier in the mids and down below. These sounded the warmest and fullest of all speakers I have here. For low volume this setup was outstanding, allowing all of the frequency range through with the finest of details emerging. The X2’s may be the ultimate speaker if you will only own one set of speakers. ; ) They improved when I inserted the new Axxess Noir under them.

With OGY and BOB’s the AGD amps was like hearing an all new set of speakers and the performance was the best I have heard from these speakers. Heavenly and natural with the Alto II Preamp. These have a wide open sound and can be tough to match to an amp. The AGD amps did these speakers justice. 

With the Pearl Acoustics speakers, The Sibelius SG, the sound was so much bigger and lush that I imagined it could be. These bring such a sound with the AGD Audion and Duets. Single driver, no crossover…pure..speaker to amp direct. What a sound. These provided the largest stage yet, especially in height. The driver in this speaker is very special and the bass goes pretty low to 38hz in room.

I was running a Pass Labs XP10 pre and loving the sound. I then inserted the AGD Alto MKII Preamp. This one is outfitted with a custom in house made R2R DAC, MM and MC Phono Stage and a streamer.

The Alto MKII was surpassing the XP10 and any other pre I had here when it came to bass depth, clarity, refinement and spatial qualities of which this preamp excelled in. Super refined meaning no ragged edges, no stridency, no offensive sound at all. The last pre-amp that I remember enjoying like this was the very expensive Nagra Classic which cost more than double of what this one cost. I would have kept the Nagra but honestly could not afford to keep it. I bought it used to fulfill my curiosities but I knew deep down I would end up selling to get my money back.

Interestingly enough, I enjoy the Alto II just as much as the Nagra and paid much less for the Alto II NEW than the Nagra was used. Here is the thing though…I had no issue selling off the Nagra but could not imagine selling the Alto II. I have bonded to it already and I know it would be tough to find a pre I enjoyed more. Sure, there are hundreds of pre amps out there and finding the right one for you will depend on your likes in design as well as sound. The Alto II is clean but with soul and adds some warmth, layering and just sounds super refined. I love this thing and teh way it starts up with its “3D’ panel is awesome.

Did I say these products from AGD are all made here in the USA? They are!

The character of the Alto II is clean, clear, immediate, intimate, bass that goes deep, body to the mids and smooth extended highs that have a beautiful glow to them. That’s it, there’s a glow and when used with the Sibelius speakers there is almost an otherworldly vibe going on with some music (but not all). I love it.

The Pearl next to the Borresen. 

Back to the sound…

No matter if it was the Duet or Audion amps There was a S.E.T. level of detail here (Single Ended Triode) as well as a S.E.T. like midrange and top end. This is part of the design and the way the GaN tech was used here, and I am not the only one comparing this to a nice SET amp. Many others hear the same from AGD amps. I will repeat that I haven’t heard this character in any other Class A, A/B or D amp before.

The bass was on a new level here from what I was used to. Again, I have had power amps in here up to $20k and these little $7800 Audion MKIII’s and $11,500 Duets were making it known in my system that they may be little guys, but they can kick with the absolute best of them. Yes, there are competitors to Albertos products but I have not experienced any that look like these, are made like these or sound quite like these. I have not heard any do what these do in regards to complete pitch black silence and overall analog vibe to the sound. 

Remember, these are power amps and not comparable to integrated amps in the grand scheme of things. These require a preamp and cables to get rolling. “Separates” as many of us call this kind of setup usually brings more refinement, more spatial qualities and less of the bad stuff that can prep its way into integrated amps.

There was a slight warmth to the mids with the Audion MKIII’s that allowed the speakers to flesh out in the middle areas. The bass was as textured, rich and tuneful as I have heard. Not dry or stiff, but liquid and very solid with depth. It was not overdone nor underdone, it was remarkable what I was hearing here. There was a magical kind of feel over the entire frequency band, top to bottom.

These bring a smooth vibe but without the homogenizing sound that some products bring with “smooth”. If you want gooey warm hot chocolate, these will not bring it. If you want cool crisp mountain air kind of bright, nope, not here either. You just hear music rather than music that sounds like it was manipulated to sound good. 

The three pelican style cases that houses each AGD product. Shipping damage will be a thing of the past when you buy AGD. 

After a few days I decided to bring in the Duets to see if I noticed a change in sound. Well, I did but it was still the same character of sound. The Duets had the same magic and same flow but they seemed cleaner and more refined in the midrange and even bass kick (felt stronger with more visceral but cleaner impact). The Duets were a bit more snappy, seemingly more powerful (they are) and a touch cleaner/clearer overall. The stage was more open, imaging more precise and organic even yet there was still that signature warmth and humanity to the sound as well. 

The Duets still retained that special something that allowed music to flow like liquid gold from my speakers. I was not sure at this time which set of amps I liked better! Both had their amazing qualities…Audion MKIII had some glow and warmth much like a single ended triode but with massive power allowing them to power any speaker I tried with them without even breaking the slightest sweat. Instruments would come out in a 3D space and be fleshed out, with space around them. Remarkable.

The Duet amps would take this same recording and do the same things but it would be cleaner (but not brighter or tipped up) and more refined and even fuller. Larger in size and scale. More snap and pop, more kick and even more exposing of the inner details with even more spatial qualities. The Duets were sending like big money $25k amps and I was amazed at the experience.

Both of these amplifiers were actually shocking me at how good they were doing in my system. They elevated my system to a new level. In fact, if I knew nothing about AGD and walked into a shop and heard the Duets I would assume they would cost over $20k.

Now, I have not been listening to lower tier gear here over the years! The Daniel Hertz Maria is/was a Class D $13k amp (not sure what they are today as Hertz raised prices). The Pass Labs X250.8 is a $15k amp. The $1500 Galion TS A75 is a self proclaimed Giant Killer (and it can slay some of them). The Aavik U-150 was a $20k integrated when it came out, the Luxman 595 is a special 100 year anniversary edition amp at double the cost of the Audion. The Yamaha A-S 3200 flagship is a $8k retail integrated. The Axxess Forte 1 is a fantastic Class D integrated for $5500 that is a detail hound. I can go on and on and on. I have had some great gear through these doors…Accuphase, Macintosh and even more. I can not remember all of it but have also had some killer tube amps here as I used to be a tube guy. Heck, I much prefer the Duets to my old tube fave, the Line Magnetic 219ia.

The AGD amps, for me, performed to a higher level in my system than any of those mentioned above and yes, other brands should be scared of AGD here as this should be the future of audio as far as I am concerned. I do not see why it should not be. These tick every single box from cheap to run, to small in size, to not running hot to bringing a sound that competes with the best there is.

Really, these are true world class end game pieces here for anyone looking for that kind of thing.

Some will say “but Steve, three+ years ago you said the XXX was your fave amplifier”…yes, but time moves on and those almost four year old reference monos have been unseated by the Duets. Tech moves on (and has). I get to hear new gear every week. Each and every week. These Duet amps… none I have owned (nor any that have been in for review) have sounded as good as these and that is without the 11 other benefits to these amps. Some get upset when I rave about gear I love, I find it amusing really and always gives me a chuckle when someone complains about me liking new gear. It always comes across as someone who is bitter due to the fact that I get to do what I love every day of the week and to them I say, YES I DO and it’s awesome. I am just a guy who speaks from the heart as I enjoy audio, it has been a passion of mine since I was 15. 

BTW there is a lot of gear I cant stand as well, it’s just that I do not talk about it and it gets sent back without review. Why waste my time being negative? I have zero negativity within my life so I just talk about the stuff I really enjoy and do not speak of the many products I have tried that were awful. Why would I? 

The Pre-Amp is Important! 

Now these amps require a preamp of course and I tested them with what I have here. The AGD Alto MKII, the Pass Labs XP-10, the Burson Voyager Class A Preamp and the Yamaha A-S 3200 Pre Out.

At the end of the day the best sound for me was with the Alto MKII without question and then the Pass labs, but they were different indeed. The Pass had more romance and softness, the Burson was more clean, precise and tipped up (Class A). I love a little bit of “romance” in my sound which means a little beauty, glow and warmth. This means I should love the Pass here, and I do. The good news is that the AGD brings some romance as well, just a little less, and it’s more refined and even more magical. But I could love and live with these amps and a Pass labs XP10 as well as a number of other preamps that I am sure these would do great with.

The Yamaha pre out brought a ton of warmth for sone reason, almost too much, though fans of warmth and fullness would love this sound. Of course, speaker choice will change this up. The Borresen X2 with Yamaha pre was too warm but with the Triangle 40th it was darn near perfect.

ROMANTIC or NOT?

The AGD Duets with Alto MKII brought a little romance. The Audions just a little more. They do this while also bringing full detail out as well as those small barely audible undercover details that are in some recordings. I was hearing things in songs that were always way back in the mix and barely audible, now more noticeable. All the while bringing smooth, open, three dimensional sound that was the opposite of dry and hard, yet also not of the wet and juice variety.

Did I say 3D? Oh yes, this system paints a big scale 3D image when used with the OGY and BOB speakers. Also with the Pearl Acoustics Sibelius which are the most three dimensional speakers I have heard to date, they gel really well with the AGD amps. With the Borresen X2 the sound is also very 3D but the largest most effortless sound of them all, the warmest and most powerful as well. Very full, rich and smooth with 3D details that emit from that ribbon tweeter.

The most magical sound I heard from AGD was the Alto MKII paired to the Duet amps that powered my Closer Acoustics OGY and BOB speakers and then the same paired to the Pearl Sibelius. Just pure all out magic and the finest I have heard these speakers sound. Then again, I am really getting deep into the sound of these with the Borresen X2 on which some days I proclaim as my favorite system of all time. On other days I say this about the Sibelius or OGY/BOB. Some days I am entranced with the AGD hooked up to the Triangle 40th Duettos. That’s the thing. It’s all good.

Not all amps sound the same as I have five here that sound extremely different from each other. No two amps will sound the same within a high end system, so finding that one amp, that special “one” can take years.

For me this process has taken 37 years, now landing with the AGD amps. Yes, I found my Desert Island amps here, the true “end game”. They deliver the design I crave which is small, light and beautiful. They offer the sound I have always wanted and deliver magic to my room nightly. They are dependable, glitch free, noise free and just work. I always say “perfect doesn’t exist in audio” but I’ll be darned if these are not just about perfect for me and my ears.

As good as the Audion and Duets are, I am told it gets even better in the AGD lineup. There are a couple models above the Duets that look so beautiful but these are out of my financial reach. I also bet the differences are not HUGE but rather just slightly different like the Audion and Duet.

The custom made R2R DAC here in the Alto II is also crazy absurdly good and sounds as beautiful as the LAIV Harmony DAC I raved about recently. That LAIV is $2700 but the DAC in the Alto MKII is similar but a bit different, more “juicy”, present, natural and again will use the word “intimate” as I swear at times I feel the artists are playing right in my room. The sound is more immediate and tangible. So no need for an external DAC here with the Alto II if you choose to include the Streamer and DAC option. This means one less box and set of cables.

This will most likely be my final preamp, maybe. Who knows I may own one or two others for different sound signatures but this one is the finest most premium looking and feeling preamp I have owned. The small size is icing on the cake for me though some may prefer a full size chassis.

I love the slight warmth it brings as well as the bass performance and 3D details. It mates with the AGD amps perfectly, as one would expect. I suggest if you are looking at the Alto MKII go for the DAC and streamer add on. This will make it almost identical to the brands top tier preamp, the $14k Andante. Alberto suggested I get the Alto II vs the Andante, so I did and wow I am happy I did just that. For $8k this preamp with its custom DAC and MM and MC phono stage is remarkable. The DAC inside of the Alto II is so good you may not be wanting for any other DAC. My guess is the DAC search will come to an end once you hear the one in the Alto II, maybe.

The Alto II design is just like the Andante. I have the one in black with RED logo here. I love the way the buttons are touch based rather than click based. I love the gorgeous 3D screen and large volume display. I love the glow of the lights on the buttons and the clean look.

WILL I BUY A SET, IF SO, WHICH ONES?

This is the tough choice. I love both of these for different reasons. I really wish I could own both. 

I love the Audion MKII due to the extreme ease of upgrading the amp with a new tube, when and if they come out with one. So far this amp is on its third tube improvement (MKIII). Ask anyone who owns these amps and they will tell you they are amazing, end game, just as I am telling you here. I’ve never heard of one owner who bought and lives with these dislike them, rather it always seems to be the opposite. They LOVE them.

While it gets better in the AGD lineup, the Audion may be the sweet spot where the best value lies. At $7800 for black and a little more for polished, these are not cheap but I look at it as the amp that ends the mono block amp chase game. No more worrying about what is next or better. When better comes out, it will be in the form of a new tube that costs $1500. Genius.

I love the look of the Duets in black. 

Then there is the Duet, which looks even cooler IMO.

The casing of the Duet looks nicer, the lit up logo on the front lights up and reminds me of some old 1950s electric company logo. Gives me a nice vibe when I listen. The Duets are also slightly and I mean slightly larger. These amps never fatigue, and one night I listened for EIGHT HOURS! I had to pull myself away.

The Duets are also upgradeable to new versions though you just can’t go to the AGD site and buy an upgraded tube to upgrade the amp. While they are upgradable, this is done by opening the amp and clicking in a new board or piece, something to that effect. But yes, these are also able to be upgraded. You can send to AGD for the upgrade as well as I am not fully sure what is involved.

I have chosen the best set of amps for my budget. I went with the set of Duet amps in the full polished version with red logo button. I almost went with black but since these will be with me for the long haul I decided to go with my heart and get the polished.

I also chose the Alto MKII preamp in black to go with the amps (doesn’t come in polished). 

OOPS I did it AGAIN

So this review cost me five figures. I did not make money here, get free amps nor do I get commission if you guys buy from Alberto. If he sells 100 amps from my reviews, I get not a cent. I am not saying these things because I owe AGD anything nor do they owe me anything. I am saying these things as they are from my heart, my passion for music and I am truly excited about these products. For me, they are game changing indeed.

I am not a dealer of audio like some YouTube “reviewers” who only review gear that they want to sell you. I am just a guy, like you. I do not work for anyone but myself so there are no “rules” imposed on what I can and can’t say. I write what I want, and only I approve of it (which is why there are typos here). I love music, audio, gear and I listen 365 days per year. I have no agenda to sell you on anything. I just like to talk about what I really feel is special within the audio world. That’s it. I do not get paid or charge to do a review either. I am not so sure how many other audio reviewers can say these things.

What I do get out of doing a review is a discount if I want to buy, but that’s a perk of being a reviewer. You do get discounts if you love a piece of gear and decide to own it. It’s an “industry discount” type of thing.

So I decided to go all in. I had to sell a few pieces to fund this as I vowed to not spend any NEW money in 2024 on Audio (have none to spend)! and so far I have held to that. I sold five pieces of gear to gather the funds for the AGD set and I have zero regret as they elevate the system more so than what was there before them.

I was thrilled with and still love other brands of course. The Daniel Hertz can be magical but really only as a system from Hertz, with their speakers. Pass Labs can be visceral and exciting as well as natural and beautiful. Naim woke up my ears. McIntosh made me feel the warm and fuzzies. Yamaha warmed my heart a bit and showed me it can compete even with the big guns. Lien Magnetic wowed me with their 219ia tubed beauty, Luxman excited my brain and many others have made beautiful music in my spaces over the last 37 years.

Music, isn’t that what this is all about?

This AGD combo communicates in the language of music, and only music. There is no grit, grime, hash, noise, clicks, pops, static, raggedness or overdone anything. These amps on the other hand are never warm, dull and un-inspiring. At every listen these pieces allow the music to flow from whatever speakers I am using and it conveys the message to my heart, soul and then brain. They also never get edgy or rough when turned up LOUD. They stay smooth and composed, easily bringing forth the flow even with complicated music.

The result is in a class of its own and unless these get wonky in reliability they will be with me for a long, long time. They will join the ranks of the “really special stuff” I am hanging onto for probably the rest of my days. The OGY and BOB’s are in this club. The HiFi Rose RS130 is as well but being that this is a streamer, I am sure tech will move on from it as well. I have never loved a digital source so much though. The Pearl Sibelius I have here is really bringing that emotional connection to the music with the AGD gear as well. More so than I ever imagined they could. While I can not afford the Sibelius right now I would buy them if I could, just to keep them on hand for those nights when I want something very special and different from the usual.

Yes, these are my desert island, retirement and end game pieces, these AGD Duets and Alto MKII pre-amp.

Of course, your tastes and ears may vary from my thoughts. There is no “one amp” that will work for everyone, so take my enthusiasm here as a guide only. Check them out if they interest you, listen to them in your system and decide for yourself. That is the only way to go with audio in this kind of price segment.

These are not cheap with the Duets coming in at $11,500 for the set and the Alto MKII comes in at almost $8k with DAC and Streamer. With a grand total of  just under $20k what this setup of Duet and Alto MKII does offer is HUGE pride of ownership, end game potential and truly next level sound. You can save a few grand and go with the Audions which are under $8k. Alberto also sells his Tempo stereo amp, which is the entry level $5500 piece from AGD. I have not heard it but my guess is that it will still retain the AGD sound. See it here. 

CONCLUSION

These amps really woke me up. I assumed I would never hear another mono amp that would greatly heighten my music listening experiences over what I have already heard. I mean, I have heard the low, mid, high and exotic side of HiFi over the last 37 years of being in this hobby. The big Krell amps, the glowing McIntosh beauties and even exotic tubes.

These amps are the first product that made me sit up, take notice and say “this is game changing”…”this is the future of high end audio”…”there is no where else to go from here for me”.

Some have messaged me telling me this one “$600 mono amp” will blow those duets away! Umm, nope as I had those lower cost mono blocks here and I did not love them. For the money they were great but that’s where it ends. Some have pointed to a $5k class D stereo amp, telling me no way the AGD’s can best it. Well, I disagree as it’s a stereo amp and the competition for it is the AGD tempo stereo amp at $5500 but the Tempo uses the same modules that are in the much more pricey Audion and DUET ; ) That is all I will say.

These amps from AGD are also works of art, and this matters when we get to this price level of HiFi. Who wants to spend $8k or $11k to get ugly, noisy, huge heavy boxes that require a forklift to lift? Not me as my back has seen better days. These amps, either of them, are works of art inside and out. The head honcho at AGD has been a treat to talk with and work with. He knows his stuff and has a true passion for music and sound. He is creating one of kind amplifiers using new tech that is taking the audio world by storm.

The upper tier AGD Gran Vivace Monoblock Amp

Make no mistake, GaN amps WILL BE the way of the future. I see no reason why they should not be. It’s almost ridiculous how good these are vs some competitors big boxes. 

These Class D amps are completely opposite of what Class D used to be years ago and what many amps deliver today in the Class D realm. Again, these do not sound like Class D amps but offer up the finest parts of Class A, Class A/B and D.

Noise doesn’t exist with AGD amps and this allows the music to blossom and flow from the speakers like liquid from a faucet. With this flow we get a large soundstage that is organic and rich but with a very revealing treble that stays smooth. Hidden details can emerge from some recordings and jolt you a bit. These will never fatigue you nor do they ever sound dry, rather there is a slight juiciness and warmth to the sound with some speakers (Borresen X2 for example are world class with the Duet amps).

These amps are spectacular and while they are high end money, they are what a high end amp should be in 2024 and going forward. 

I tested these with several sets of speakers. With the Triangle 40th Duetto they are a dream, best I have heard these speakers sound with rich big bass down to 38hz and silky wide open treble with a gorgeous midrange. Notes hang in the air longer than most as these amps also do the spatial thing very well, though again, nothing is overdone. The images are big, bold and rich and these create sound that touches the heart, the soul and has the ability to bring out emotions within you. They did for me.

One of the best sounds I have experienced with these amps is with my main reference speakers, the OGY and BOB combo. Just breathtaking good. Wide open and sublime.

The Borresen X2’s are warm, rich, fluid and sound massive with the Duet and Audion. On many nights I feel this is the ultimate setup for me and for anyone who loves very big, rich, full and warm yet very detailed presentations. So so good for low volume as well.

The Pearl Sibelius are pure magic with that single full range driver and no crossover. These are for those who do not listen at crazy loud volume yet the Sibelius speakers are some of the most magical I have heard yet with strings, acoustic, classical and jazz. Either way, all of these sound divine with the AGD system in place.

Galion Voyager TL’s retain their warmth and fullness but the treble pops a little more making these very affordable sneakers sound much more expensive.

I am sorry if this seems hyped but these deserve all of the hype they receive, so really, I am not sorry! I must hype these as I want you to know how special they are. They really are that good. Take a look around the old internet and see reports form users, as a few have posted on forums about these.

I just could not imagine not having these in the system after I have experienced them. That’s the thing. DO NOT listen to these in your system if you can not buy them. If you do, then they may just haunt you until you hear them again. These can touch me on a spiritual level and that sound crazy to some of you, I know. 

Yes, these are end game wether you go for the Audion or Duet. I am sure the higher end models do even better but probably by small amount, like between the Audion and Duet. Maybe it’s bigger. Maybe one day I will find out. 

One more thing..

When I can buy a set of mono amps that are small, light, runs cool, look amazing, are upgradable and sound heavenly why on earth would I want anything else? Well, I wouldn’t. 

OH!!

Also, these ship in a bulletproof way. A medium sized shipping box holds a pelican style case with the amps perfectly fitted inside, along with two audiophile style power cords and an instruction manual. Never seen any piece of audio gear shipped like this, unless they were in the $20k and up price range. Even the $7800 Audion amps ship like this. Shipping damage should never be an issue. The pre amp shipped the same way so BRAVO to AGD for this.

As a reviewer I have received maybe 6 damaged pieces over the last 4 years here. Not many but these damages resulted from the bad packaging that some have implemented. It’s nice to see a company think of everything.

NOW…if you go out to and buy these and do not get the magic I am, do not blame me! Remember, our rooms matter the most, then speakers, setup, source, amps, preamps, etc. Maybe I hit the jackpot for my room, the speakers I have here, etc. That is why it is wise to audition if you can, in you own space. Do research and do not buy based just on my word. While these are the finest I have heard, maybe you will not feel the same. Audition if you can, but only audition if you can buy them as they may hook you just as they did me. 

Be sure to check out as many thoughts as you can on these beauties to see if they fit within your tastes. For me these are the ones I would take to the grave! Remember, these amps are also able to be upgraded vs buying an all new amp. That’s the golden ticket my friends.

Heirloom amps, that’s what these are. Heck yea, Desert Island amps. Either term fits. The preamp is the same deal. You can go up the ladder at AGD as they have a couple of amps above the Duet but those are for even deeper pockets. You can see all of what AGD offers at their website below. 

CHECK OUT AGD’s WEBSITE HERE. 

UPDATE AUGUST 2024:

As stated, these are 100% end game amps for those who can afford them. Amazing quality in all ways. Unfortunately I had to sell my AGD gear as in all honesty I spent too much on them and I could NOT really afford them. So I sold them to a new owner who loves them and has stated I could come listen anytime I am in the area. Love when that happens. These amps will be missed but my “wants” should not be more important than my “needs” in life. Finest amps I have heard to date. I replaced them with the HiFi Rose RA280 which gets me 85% there ; )