A Masterpiece. The AGD Allegro Integrated Amp Review.

The Search Ends. AGD Allegro Integrated Amp Review.

By Steve Huff

Sit back, relax. This is a 7800 word review taking a deep dive into this new high end all in one from AGD. I spent two weeks just writing this one so I hope you enjoy! The video will be up soon as that will take more time. 

A few years back I reviewed and purchased a beautiful set of mono block amplifiers from AGD based out of California called the DUET. Those amps were the ones that I called “Amplifiers of the Gods” due to their small size, cool running nature, deep silence and all out gorgeous human kind of sound. The kind of sound that was pristine yet full of life and emotion, with a dash of warmth. Almost perfect amps, and in some ways, they were perfect in day to day operation for me and my ears. The Duets got so close to bringing a tube SET amp sound yet with the power and speed of GaN Class D that the memory of them always remained. They had snap, power and a wide soundstage with precise imaging that created a holographic image of sound.

The Gorgeous AGD Duet Amps in polished chrome

Since sound is subjective and we all like different things, I do not feel any amp can be “perfect” for everyone when it comes to sound. Even so, the GaN based DUET amps were completely silent in operation and looked like something from the art deco era and 2020’s combined.

For me, the sound of the AGD amps I have heard so far is quite beautiful, though not a sound I would call bright or sparkly nor are they dull and flat. The sound of AGD class D is quite different from other class D amplifiers I have heard. As hinted at earlier, the sound of AGD (to me) is more like a SET tube amp mixed with the speed of class D, for real. The AGD sound is not like typical Class A/B, A or D. It has the palpable feel of Class A but with the refinement, efficiency, silence and smooth nature of the best Class D GaN. It’s quite incredible really.

Up until the new AGD all in one Allegro arrived I had only heard the Duets and the latest Audion MKIII amplifiers from AGD. Both are stunning and offer up a similar kind of sound quality but the DUET brings more power and a dash more refinement/clarity vs the Audion MKIII. The Audion is the amp that brought serious attention to AGD in the beginning. I’d say the Audion has a smidge more warmth and is mellower than the DUET and those “tubes” that stick out from the Audion are what makes them so unique. Gorgeous, small, light and highly efficient.

The Audion MKIII uses tubes to house the actual power amp section. This is genius as you can upgrade with a change of the tube. These are gorgeous in the flesh and are drool worthy on their own. Again, you can get the latest version of the amp by buying the latest “tube”. Genius. 

I have been lucky to have been able to hear countless class D amps from many brands, big and small. For these ears AGD sits among the top I have heard when it comes to feeling life, connection, beauty and emotion from the music. This AGD sound is not the Class D from a decade ago of which many were quite lean, grainy, boring and lackluster. The AGD amps are also not anything like the cheap class D amps you see on Amazon in any way,

The AGD amps use proprietary tech where the mastermind behind it all, Alberto Guerra, creates modern day masterpieces of audio art using GaN technology. These AGD amps bring a sound that fully brings the emotional connection to the music as well. Yes, AGD amps speak to the heart.

AI Take: Yes, AGD (Alberto Guerra Design) amplifiers rely on heavily proprietary and patented technology. Unlike many other manufacturers who buy off-the-shelf Class D modules (like Purifi, Hypex, or Pascal), AGD builds their systems from the ground up using exclusive, in-house engineering. (this is why they are so good). 

The AGD Alto MKII Preamp with Duet Mono amps in black. I had a set of black and polished chrome here and when I bought mine back then I chose the polished for their classic look. Even so, this setup in all black looks stunning. AGD is a fave of mine for sure when it comes to design as well as sound. As you scale up the AGD ranks you will get more snap, power and well, “more” of what makes AGD so good. I wondered how the Allegro would do. 

Regrets in Audio Suck

Because I review audio gear I am lucky in the way that I get to hear a lot of HiFi gear. As a kid who started in this hobby at 15 my now 57 year old self sometimes feels as I am living a dream. One week I may get gear that I would normally never be able to afford, or what I would deem”fantasy” level gear, to review or evaluate. The next week I may get an affordable piece that surprises me like this one.

Just getting to keep these pieces for a few weeks is a pleasure and treat but there is always something else on the way so the fun never seems to end. Over the years of doing this I have heard starter, mid, high and exotic level audio gear and I have enjoyed pieces from every cost category. I have went down the rabbit holes of the exotic and the very affordable realm of audio in my personal life as well almost going broke just to try an insane setup (that I ultimately did not love).

I will say that as many amazing amplifiers, integrated amps and mono amps that have come through my space I only have just a few that were favorites and have stuck with me via the memories made with them. One such set, probably one of my biggest regrets in this audio hobby, was letting go of the AGD Duet amps. I let those go due to some personal $$ issues I had at the time, and am just now and still getting worked out. There were many days I sat here wishing I could have kept those amps. Of all the amps I have had, those were the ones that really truly stuck with me. As good as some of the others are they often come with high heat (Class A), heavy weight (old school monsters), high costs to run (class A) or noisy toroidal transformers. The DUET had none of these negs plus they had the unique ability to make heart touching sounds emit from my speakers. 

Maybe in the old days size mattered in HiFi but not today. Small new tech can be just as good if not better than big old tech. If you ask me my personal opinion I feel very well done Class D GaN is the way to go these days.

So just as I was going down memory lane with the DUET’s I was asked by Alberto at AGD if I would like to check out their newest piece, which is the Allegro integrated all in one amplifier. This one has it all inside including an updated streamer, an R2R DAC voiced by Alberto, a complete MM and MC phono stage, a headphone amp and of course the AGD amp section which puts out 250 WPC into 4ohms and 125 WPC into 8 ohms.

Normally, some boxes like this bring compromises with all of this stuffed inside one small enclosure. When you stuff a phono stage, a DAC, a streamer and an amp inside of one small enclosure there can sometimes be a higher noise floor, cracks, pops or just not the all out sound quality we can get from using separates.

With the Allegro, AGD claims there is no compromise here with this all in one so when they asked me if I wanted to review it, I was all in. I knew I loved the sound of their amps so I was excited to see what the Allegro would be like when using it all on its own. Everything here in the Allegro works as its own specific component as if they were separate boxes. The major pro here is the fact that you will not need a mass of cables or system matching with the Allegro. This has all been done by Alberto, basically making sure everything inside works separately but “as one”.

The Allegro is a small all in one built to an extremely high level. This looks and feel and sounds like an exotic level piece but sits in the high end realm at $15k. You will not need a streamer, a dac, a phono stage or a head amp to make music. This has it all and brings 250 WPC of refined sound into 4 ohm loads. 

THE DESIGN

Wow. When this showed up in its own pelican style flight case (as all AGD amps do) I was amazed to see the small size yet solid hefty and artistic design. It looks much like their $13k Adante or Alto preamp but this chassis houses everything, somehow. It’s exquisite in looks, pure class and style with a sheen to the silver finish that looks like pure luxury. The knobs on the front are solid and feel like they belong on a high end audio piece and I do not always see this. The carved top with a screen type of mesh allows ventilation and is a nice design touch. This allows the Allegro to be cooled down naturally but it doesn’t run hot, just warm. These vents are also on the bottom.

I love artistic design in audio and I admit that for my tastes this Allegro may be the best looking all in one integrated amp I have had here. It’s charming and classy at the same time. While the Allegro doesn’t have fancy (some would say gimmicky) VU meters the simplicity is one of the things I love about it. The big clean display that is easily seen from across the room is nice as well. I do not need bling but rather value, ease of use and performance above all else. The looks, feel, materials used and the unibody style construction is top level. It looks modern and feels modern, and if AGD pulls this off and the performance is as impressive as their separates than this will be something very special. It’s small, compact and yet hefty so it feels as good as it looks and it looks like it should cost what it does.

What would it cost to obtain an AGD amp (At least $8k for Audion MKIII or $12k for the DUET) with an AGD pre (At least $7k for the Alto II or $13k for the Adante II) a custom R2R DAC (at least $5k for a good one) a class A head amp ($2k) and streamer ($2k)? All at this level? Well, this would cost much more than $15k and I would guess it would take $25k in separates to top the quality of what the AGD Allegro has inside. Maybe more when we account for cables as you will need quite a few more if going to separate boxes.

With AGD

With AGD you get more than sound when you buy one of their offerings. You also get top tier presentation and amazing packaging with the pelican style flight case. You get masterful design and looks. You get small size and high end performance. You can get “cheap” Class D amps all day long and I have tried many of them. With those cheapies you get lesser in sound with some edge, dullness and flatness built in for your non enjoyment.

With AGD the build, design and well everything is as good as I have seen in audio, even the exotic realm. As for others like Orchard Audio, HiFi Rose, Atma-Sphere, LAIV and even Devialet we can get really great class D but none come with the all out unique vibe of AGD.

I prefer the silver but the Allegro also comes in black with red highlights. I’d love to see the AGD logo up top be the lighted power button as with the DUET and Forte amps from AGD. 

The Allegro is a Five in One

THE STREAMER

So there is a full streamer on board here as the Allegro is designed to work as one, with every section made to mate perfectly with the system as a whole. The streamer here is not the typical type as it is one that doesn’t work well with Spotify or Tidal connect. This is truly enhanced for Audirvana, Qobuz Connect and UpNP. In fact apps like MCONNECT will work perfectly as does Audirvana or which I signed up for to test with the Allegro.

The Allegro streamer does work quite well with Qobuz Connect via the LAN input, of which you will need to hook up to use the steamer here. The Allegro does not use WiFi so it does need a hardwired ethernet connection, which is easy these days for any room with mesh networks. Qobuz Connect worked a treat but Tidal Connect not so much.

The good news is that when using Audirvana I connected and streamed with ease using Tidal. I also could easily use Spotify Lossless by choosing the Allegro Bluetooth input, which shocked me as to how good it sounded. I must say that I was never a bluetooth kind of guy but it has come a long way. I had no issue streaming in this way though it did soften the sound just a hair vs using Audirvana or the MConnect App. Volume was lower as well when using BT so had to bump up the volume dial.

Overall once I figured it all out it was super easy to stream to the Allegro. I found no real improvement in sound when plugging in a Matrix NT1 or Eversolo T10 streamer to the USB INPUT vs using Audirvana with the Allegro direct. This means the Allegro starts out with a bang as the internal streamer sounds just as good as using a $4k Matrix box when using Audirvana or Qobuz Connect.

For me I prefer using the apps natively from Tidal, Qobuz and Spotify and I can only use the Allegro in this way with Qobuz. I like convenience and sound quality both. For most though, especially if you use Qobuz, the Allegro built in streamer is all you will need and sounds/connects perfectly. So to be clear the streamer here sounds as good as the $4k Matrix NT-1 when streaming Qobuz Connect.

If I solely used Audirvana or Qobuz it would be perfect and all I need in a streamer.  Maybe this fits your criteria? It all depends on how you want to stream really but all in all the streamer here is capable and sounds amazing. If you enjoy using Tidal and/or Spotify connect then adding an external streamer, even a WiiM Ultra on the cheap would be useful and yes, I tried it with great results. If not you can run Tidal perfectly with Audirvana and Spotify Lossless via Bluetooth. Of course there is ROON as well but I am not a ROON user so this was not tested.

After a couple of weeks I hooked up an Eversolo T10 Streaming Transport to the Allegro and this was much more convenient for me as I enjoy Spotify Connect lossless. Sounds amazing as does streaming other services through the T10.

THE R2R DAC

The DAC inside of the Allegro is an R2R type and it is a smooth organic sounding DAC vs anything very analytical. It is liquid, rhythmic, spatial and brings depth to the soundstage, sounding very analog yet has plenty of life and big resolution. It sounds like real music vs hyped up HiFi so do not expect shiny brightness or bright illumination up top. Rather I hear a seriously liquid and rich vibe and one that mixes body, midrange beauty and sweet treble together with some holographic and high res renderings. It’s a supremely musical DAC inside of the Allegro but it doesn’t get overly smooth or dull as there is a speed and resolution here as well that keeps timing perfect. It’s fast yet smooth and while not as transparently open as some others I have here, it’s a nice musical fluid sounding DAC that will never offend or bring fatigue. It sound likes silk vs glass. Light maple syrup vs purified water. It mates with the amp section just right. Synergy included.

Think more like analog vs digital sound here. More warm and smooth vs excitable and dynamic. This DAC will never fatigue but also never has me bored. It’s quite beautiful in fact, and after a week or so I was really sort of addicted to the vibe of this DAC inside of the Allegro.

THE PHONO STAGE

The Allegro has a fully featured MM and MC phono stage built in as well. Since I do not have a table at this time, I could not test this part of the Allegro. I will assume it is very good as the rest of the Allegro is. If the Allegro stays long term I have plans to add a table when we move and I get the new room setup. I will then do an update around Christmas time 2026. The Allegro phono stage is compatible with low and high output MC and MM so it is very versatile.

THE AMPLIFIER

The amp inside of the Allegro is not the most powerful on offer from AGD but it does bring plenty of power for most any speaker to be easily driven. Bringing 250 WPC into 4 ohms and 125 into 8 ohms the Allegro brings a sound that is much like Class A but with traits of modern very well done Class D as well. There was no issue driving any speaker I had here that ranged from 87DB to 92DB efficient. I noticed that some AGD website text says 200 WPC and some say 250 WPC so not sure which it is but either will bring enough power to drive almost any normal speaker. I’d say the amp here in the Allegro is not quite as snappy or open as the DUET but not quite as warm as the Audion. It’s somewhere in between but has the same drive, character and rich sounding vibe.

The Allegro is also a high current amplifier…

• Peak Output: It features an impressive maximum peak output current of greater than 50 A.
• Power Output: The AGD website says it delivers 250 Watts per channel into 4 ohms.
• Gallium Nitride (GaN): Built on AGD’s proprietary GaN power stage, the amplifier uses ultra-fast switching to handle demanding low-impedance loudspeaker loads and musical transients with ease. 
• Transient Capability: It can even support a peak power of 4 kW for short bursts (100 ms) to keep dynamic authority. This is crazy but crazy cool. 

In my opinion, being high current is more important that all out wattage as I have found high current amps always seem to have the most drive or perceived power when driving speakers. They just seem to have more authority and control and the Allegro is no exception. It drives speakers with ease and controls them with a tight grip all while staying 94% efficient. Crazy cool. We normally do not think “High Current” when we think of Class D, at least I never did, but the AGD amps would be considered high current.

THE SOUND

The sound of AGD is quite unique and also quite different from the sound of a standard Class A or A/B amplifier. While it sounds more like the modern Class D amps there is also a Class A “SET” kind of quality as well when it comes to the sound. So imagine the power, drive, smoothness and impact of modern very well done Class D melded with a little bit of chime, immersion and speed of the best Class A and A/B. Add in some of that palpable and realistic SET tube sound with the imaging and soundstage and you have quite a beautiful sound. It doesn’t sound like one of these, the Allegro sort of sounds like a mix of all three types.

With the SV Audio Gro speaker (shown above) from Denmark the Allegro brought forth a luscious and gorgeous room filling sound that never offended my ears. There was some nice immersion and some warmth. Bass was just incredible with a full bodied vibe in the mids as well. With the Fleetwood Helios the sound was warmer than usual and yet remained large in scale and had an immense effortless flow. The Helios sounded as good as I have ever heard them with the Allegro. Testing some new $1500 bookshelf speakers (The Solstice) from Triangle brought more of the same. A deep sound with a solid foundation, ultimate refinement and everything laid out in a “just right” way.

There is no sizzle here and no hardness to be found as the music that flows from my speakers has a complete refinement to the sound. There is 0% grit, grime, noise or flatness but a sense of body and soul that seems like “hey, this is what music should sound like”. Some overly smooth amps or DACs can sound flat and/or dull when you are used to a higher end sound but the AGD Allegro stays full of life. I have to stress that after a week or so listening I was hooked to this sound. I always know when I truly fall for a piece as I cannot stop listening. While this happens often with the good stuff, sometimes it’s different.

There is something that just brings the feels as well with the Allegro. Can’t put my finger on exactly why but it’s a unique and special piece.

The soundstage is wide, a bit tall and has very nice depth but I think the DUETs may bring a wider and deeper stage, though with less density and body. Whether I had the Fleetwood Helios in play or the SV Audio Gro providing the beats the sound was a bit earthy, warm and yet also slightly moist and alive at the same time with the Allegro.

Imagine a sunny day with dew on the leaves and birds singing in the early coolness of the morning. Ahh yes, there it is. The Allegro sound. 

I will say that the Allegro was an amazing match to the new Triangle Solstice 3 speakers. These are brand new from Triangle and I have had them here for a couple of weeks now, for review. When these were hooked up I had the highest level of immersion with the Allegro. There was also more air and the sound was beautiful. Crazy as these are more in the affordable lane but image like a beast. In some ways I prefer the Solstice with the Allegro vs even the SV Gro.

No, the Solstice are not “better” than the SV Gro but they sound amazing and cost tens of thousands LESS. Diminishing returns at play as usual. I can say that the Allegro, streaming Qobuz, Tidal or Spotify lossless into the Triangle Solstice was a small to mid sized room marvel. The Allegro make these sound like a much more expensive speaker and I wouldn’t shy away from making these my main speakers with the AGD amp. They really are fantastic.

As for the all out sound of the Allegro there was a familiarity to the sound that I remembered from the DUET amps I reviewed prior but I felt as if this time, the sound was just a touch warmer still with a bigger foundation and more heft to the sound. I had a feeling it was the R2R DAC that was bringing the warmth so I decided to test this theory out.

The SoulNote D1 MKII DAC – See my review HERE

I placed in a $4550 SoulNote D1 MKII DAC that I know brings an amazing illumination to the sound but with big bass and a gorgeous 3D midrange. When I attached this to the Allegro, using a dedicated streamer to keep things simple, I was amazed at the difference in sound. With the D1 MKII I was now hearing a more illuminated and lively treble, more dynamics and bigger bass. This was still smooth but less so. There was now less warmth as well.

While the R2R DAC inside of the Allegro is mature, refined and silky the SoulNote D1 MKII showed me that the amp in the Allegro can bring the house down with energy, drive and dynamics as well. When it was all said and done I sort of preferred the DAC inside of the Allegro. It was never blowing me out of the room with energy but rather kept me deep in my seat with that human kind of emotional sound. This Allegro proves how important a DAC is within an audio system.

I feel it’s pretty cool that Alberto chose an R2R style DAC vs just throwing in a modern day chip as most do. He did his homework before designing this little all in one and as time went on with it I never wanted to take it out of the system. It hooked me just as the DUET amps did.

I loved the energy of the SoulNote though. It is a giant killer if you seek energy, dynamics, sweetness and a huge 3D stage. The Allegro brings some of that but also pulls me in via the heartstrings.

For fun I tested the insanely good $349 “Warmer” R2R DAC with a tube buffer

So the Fiio Warmer DAC is my pick for best affordable DAC EVER, really. At $349 it looks and sounds better than it has any right to. It shames some DACs in the $2k area and sounds a bit open, a bit juicy and with some warmth yet it’s not what I thought it would be. For $349 it is a no brainer and I found no weakness if you seek an affordable DAC that sounds beautiful. When I added this to the Allegro I had no idea what to expect but it brought a sound that was somewhere between the dac inside of the Allegro and the SoulNote. It wasn’t quite as soulful or refined as the built in but brought a little more shine up top, in a warm kind of way. Just a bit different but very refined, more open. Soundstage was wide and imaging was fantastic, even with this $349 DAC.

This Allegro amp allows you to hear what any external DAC truly sounds like. The Warmer DAC couldn’t match any DAC I had here (that all cost much more) when it comes to refinement and all out immersion though. I still heard an ever so  slight digital sheen with the Warmer if I paid attention and used OS mode. Even so, for the money it just cannot be beaten. Does the Allegro R2R sound better? Yes as the Allegro DAC has a more refined sound. Still, it sure is fun testing other DACs and hearing what they do to the sound of music.

AS IT IS

What I found is that when I used the Allegro as the all in one that it was designed to be it also brought the best experience and was showing me what it was all about. If I add an external DAC I am now changing the whole idea of what the Allegro is about. I would now be better off with one of their amps and a preamp vs the all in one though that would cost me nearly double.

I will say that I personally did prefer the Allegro with an external streamer for using the connect features of native apps like Tidal and Spotify but I an extremely picky as well. I loved the Allegro when using Qobuz Connect direct as well. The built in streamer offered a balance of going to Bluetooth, which is so much better in sound than what we had a decade ago. I could go direct with Tidal using the LAN setting of the Allegro with Audirvana for the all out best sound quality of that platform. Seeing that the Allegro also allows for airplay you can stream via that as well to the LAN input.

The remote is very nice

THE REMOTE

The last time I had an AGD preamp, the Alto, it came with a crappy (sorry) thin Apple TV like remote. Heck, even the $529 Wiim Amp Ultra has a better remote than that old AGD remote. I am happy to say that the Allegro shipped with an all new gorgeous metal remote of supreme quality and it feels great in the hand and looks pretty snazzy. So much better than those old cheap remotes and a much better fit to the price tag of the Allegro. Bravo.

The Allegro with a set of Verum Headpohones. Man this is a sweet setup. 

The Headphone Amp

Yes indeed the Allegro even has a built in headphone amp and I tested it briefly with my Verum headphones, the OG model. It sounded fantastic but since I am more of a 2 channel speaker guy I did not get too involved in the headphone performance. I just know that I would be happy with it if I were a guy who enjoyed this style of listening.

You should know that my reviews are sort of personal as I do not do this as a job, I do this because I enjoy it. Yes indeed, I let my personal opinions sneak in. If I worked for someone else it would be part of my job to fully evaluate the head amp and write about it. Well, I just do not get into headphones much these days so I will let someone else evaluate this part of the Allegro. I am sure there will be more reviews of this piece soon. With the OG Verum? No complaints and they sound better than most I have used with them when using the Allegro.

Letting some personal thoughts creep in again after a few weeks of listening again as if I wanted a high end integrated amp today the Allegro is the one I would buy. This is after hearing integrated amps from all of the big names and then some. It really does act “as one” and really is deathly quiet with no noise. This is huge and part of what makes it sound so good. It’s the quietest integrated I have ever reviewed by far.

ANY COMPROMISE? 

So after listening to the Allegro as an all in one for many weeks I have come away very impressed. I sort of knew I would be as I love not only AGD design but the sound that their amps produce. Things such as the small size, lighter weight, zero noises or buzzes, cool running, amazing 94% efficiency as well as the refined and rich sound these amps produce just hit me in a new kind of way. Many will ask me “is there a compromise here”?

So wrapping this section up the weakness for some may be in the streamer as it is not quite as convenient as using a dedicated streamer such as an Eversolo T10 Transport into the Allegro USB input. You can stream Qobuz Connect direct to the LAN input, easy and sounds remarkable. You can use Audirvana for Tidal or Qobuz but this entails keeping a computer on at all times and using your phone app as the remote. There is also bluetooth streaming which connects perfectly and solid each time. This also sounds much better than I could have imagined and there have been many days I sat for hours listening to my Spotify Lossless playlists in this way. If anything Bluetooth is just a bit more mellow in sound, pinched. Airplay is here as well.

I enjoyed the Allegro all on its own and I also really enjoyed this setup here of Allegro, T10, Warmer DAC and all plugged into a Synergistic Research Powercell SX12. The Allegro is a great all in one but also a great control center as if you want to change it up later you can add pieces to do so. It’s not needed but it all works.

All in all I enjoyed using Airplay, Audirvana and Bluetooth when using the built in streaming functions. When I attached a Matrix NT-1 or Eversolo T10 streamer to the Allegro I do not feel like I gained a ton in sound quality but just a bit more ease of use with the ability to use the “connect” features of the apps.

The built in R2R DAC is a very fine DAC indeed. Almost a bit like a more refined higher end Denafrips R2R kind of sound and it sounds supremely analog vs digital. The DAC in the Allegro brings a warmish “full bodied” vibe but with some impact and drive that deliver the goods whether you are listening to old Jazz vocals or modern day electronic music. It never sounds hard or overly excited so no fatigue will ever creep in. If you enjoy the warmer full bodied fluid kind of sound, the Allegro will deliver that to you in a beatiful way. Spatial music such as ambient and electronic music is unreal good with the DAC inside of the Allegro. It does immerse but not to the level of say the $25k Audio Mirror WAVE DAC. Even so, it’s such a different sound and if you seek an analog type of digital along with the SET like sound of the amp in the Allegro, this may be your personal ticket to aural pleasure.

The Analog part comes from the smooth and yet full bodied sound. The SET part comes from the way the Allegro delivers details and resolution with a slight transparency that allows us to see a bit into the recording. The fast and powerful part comes from the amp itself, which is fast, powerful and with superb bass performance.

I tested the Allegro as a preamp as well going into the Unison Research DMV2 power and which has a bit of class A and Class A/B. Made in Italy. The Allegro is quite an amazing preamp as well though the weakness is no XLR out, just RCA. The small size kept that from happening. 

I did add a couple of external DACs and all brought their own kind of sound. The SoulNote D1 MKII brought energy in the treble with big time dynamics and depth. The Imersiv D1 brought massive immersion and even greater depth where the little LAIV Verse brought big full bodied warmth, just a tad less detailed, less silent and less open as the built in Allegro DAC. The Warmer DAC from FiiO did so well with a nice open stage with warmth in the mids and somehow amazing silence.

Each DAC sounded different which meant the amp here allows us to hear what these DACs are doing with ease. Overall I enjoy the Allegro with the built in DAC the most and this should not be a surprise as it was designed to sound best with the amp and streamer. I also like a full bodied kind of vibe vs all out transparent and leaner. 

Even so, it is easy to add an external DAC if you ever wanted a change up in the flavor of sound. The Allegro may be an all in one but it kind of acts as it is made of separates as well. I even tested the Allegro as a preamp into a Unison Research DMV2 power amp and it did very well bringing another sound to the unit. The Unison is Class A/B but I was impressed with the Allegro as a preamp here, even using RCA outs as the Allegro does not have XLR pre outs. It is just too small and I feel if it did have XLR it could hurt the Alto or Adante II preamp sale. The Adante II, no doubt, is a better preamp than what is in the Allegro but it will cost you close to what the Allegro cost.

So we can alter the sound via an external DAC if you wish but all in all I feel the Allegro is meant to be used and enjoyed for what it is, a brilliant all in one. There is no “weakness” here at all in any part of the AGD Allegro sound as everything here works as one to bring a performance that is meant to touch the heart with a sound that is all out as musical as it gets, but with soul, life and depth as well. I guess you could get a more open sound, an even larger stage and more 3D with an Adante II and DUET set for $25k. That’s $10k more than the Allegro.

This Allegro did well with every speaker I hooked up to it. Each time it brought a soulful sound with some warmth and beauty allowing even some old 80s recordings that normally sound thin and lean to sound so much better and with body and groove. I can’t stand amps that make music sound sterile and the AGD Allegro did not do this here at all.

Overall this should be compared to one other all in one I loved and that is the Devialet Astra shown above. The Astra is a $20-$25k all in one so it’s more pricey than the Allegro. The Astra is thinner but larger/flatter and has a cool remote as well. The Astra is Class D (though not GaN) and has a streamer built in as well as the DAC. It’s a very similar type of product but the Devialet is made in France and the AGD in the USA. Both of these, the Astra and Allegro sound different and look different.

If I had to pick one today, right now, it would be the Allegro as it’s quite a bit more affordable vs the Astra and I just adore the AGD sound and design. The Astra also gives up nothing in features and style. The AGD for me just has a little more charm but the streamer in the Astra does offer up the “connect” features for super ease of use in that area so take your pic. For the extra the Astra costs one can buy a nice dedicated streaming transport and add it to the Allegro and still have thousands left over. I’d say for me personally, an Eversolo T10 and Allegro would sit in a massive sweet spot of high end streaming.

I also compared the AGD Allegro to the ModWright KWH 225i integrated (below) as well, and these two have a completely different sound. The MW 225i is more illuminated in the treble and cleaner/clearer in the midrange. A lot of “snap and punch” and possibly closer to the DUET sound vs the Allegro. The all in one from AGD is a bit warmer up top and in the mids, fuller through the mids and more layered in the stage. Not as “wow” at first listen vs the MW but this is where things got interesting.

I love the ModWright and was wowed with it anytime I put it into action. It’s much larger, heavier and not as all out insanely quiet as the AGD. It doesn’t have a DAC or streamer nor head amp, the 225i. The USA made ModWright comes in at around $11k and it is among the finest integrated all analog amps I have reviewed, in the top 3. The MW brings more shine and has a brighter top end but the AGD is more soulful and refined.

I love both of these but the AGD gives more with a DAC, Streamer, Head Amp and Phono Stage. It’s smaller, lighter, more efficient and will always be as silent as an ant or spider. Neither of which make noise. Silent. It cones down to your preferences really. The MW brings that true class A and A/B chime and a more illuminated energy.

The business end of the Allegro features all of the inputs and outputs you can ask for. There is also a subwoofer out here as well for easy subwoofer hook up. It all feels solid and built to a high level. 

Other than the Devialet Astra I have not had any all in one here that competes with the Allegro in any way and given that I would take the Allegro today this tells me the Allegro is a rare find. I rate the Astra very highly for an all in one. I just prefer the charm and sound of the Allegro as it is just different.

Of course I must mention the Heaven 11 Billie MKIII (below) as it too is a class D integrated with a preamp and DAC. The Billie uses tubes, is small and runs cool as well. It also has a nice remote and class D power. It is not as refined as the Allegro in build or design. It is not as refined in sound. It’s DAC is not to the same level though it sounds great and is another wonderful all in one I recommend.

The Billie MK3 is a fantastic piece for what it costs. The AGD Allegro is an amazing piece for what it costs. The Billie will save you $10k or so but I personally do get that extra $10k in enjoyment from the Allegro which is rare to say as well. Will you? Maybe or maybe not. It all comes down to priorities. Music is big in my life so it is a priority above many other things. All of the other amps I am taking about here are also excellent. Just varying levels of it. So the Billie rocks, the Astra rolls, the ModWright is a powerhouse of sound and the Allegro is about class, refinement and soul.

The Allegro is an indeed an all in one that has the build quality of the best there is and the packaging that is better than the rest. There is even a great 5 year warranty that transfers to new owners if you sell your AGD gear. Big pride of ownership as well with all AGD gear. 

I have to say that AGD has become one of my fave audio companies today and I rate them as equal or above many of the famous and well regarded old school brands. Many of these old big brands have now been taken over by corporate interests. AGD is more of a boutique HiFi company and this means care is taken with each piece. Also, for those who care about such things, AGD is made in the USA. Smaller companies always seem to have that massive pride and passion in what they do and this is why many times I seek out the small brands who are still run by the people who started it all. AGD, ModWright, Pass Labs, Heaven 11…all small but with big passion behind them.

The Reality?

The future is here now for high end HiFi and it no longer means hight heat, horrible efficiency or buzzing transformers. Tech has moved on so now the audiophiles just need to accept the new (if they want to). Not everyone will want a smaller more efficient amplifier as some love that old school 150 lb tank that heats the room. It took me a while but I fully embrace AGD’s version of Class D and the Allegro is an all in one masterpiece no matter the class of amp inside. It’s a heck of a sound and one without any big weakness. For me, the Allegro has the looks, the build, the ease of use and the sound. It has it all in one small package and yes, I mean high end quality.

If an all in one is not to your liking AGD makes a pretty wide selection of amps and preamps which may be even better but how much so I cannot say. The Duets, The Forte, The Audion, The Gran Vivace MKIV and the Solo are all drool worthy amplifiers on offer from AGD. I’d love to hear the Forte, Gran Vivace and SOLO one day. I can only imagine how magical a set of any of these would be with the AGD Adante II preamp. As we climb the price ladder I would expect more transparency, more 3D depth, and more snap and detailed imaging. Those are some of the things we get as we pay more.

The Allegro being an all in one, the first and only integrated amp from AGD, the sound sits between the Audion and DUET which is very nice indeed and honestly the sound is pure AGD as all I have heard from then have a similar house sound. Beauty, warmth, resolution, speed and body to the music.

A mock up of my new audio room that I will start to build out in August of 2026. We are moving to a new home in a very small town and out of the woods. I will have a normal air conditioned and slightly larger space with my own bathroom ; ) I think the Allegro may be a perfect fit but we will see. 

As I get older I appreciate the calm, serenity and the beauty of music more than the sizzle, crash and sparkle. I value balance vs all out force. I value eery silence vs crackles and hums and a deep large soundstage vs just a wide one. I seek that connection to the music as I sit and get lost in the sound, the notes, the vocals and instruments. I seek soulful sound and to hear the soul of the performer at playback. The Allegro brings all of this. Yea, there are such things as “deals” in the high end. This is one of them as it is one serious all in one that can truly end the search for “better” in an integrated amp.

DISCLAIMER

No, I did not make one cent doing this review as in, I was not paid to do it. I do these out of pure enjoyment though it does get tough sometimes to keep going without pay. These reviews take a ton of time as I spend quality time before I even start to write. These reviews make money for the manufacturer but not me. If you want to help me keep going or if you found this review helpful I do have a membership at my YT for $5. Every little bit helps. You can join here.  Thank you in advance.

See more about the AGD Allegro HERE at the AGD Website

The AGD Allegro has been awarded my first Gold Award!