AGD Gran Vivace GaNTube Monoblock Amplifiers & Andante Pre-DAC streamer Phono plus Ocean Way Eureka loudspeakers = Wow!

I love when industry veterans get excited by new discoveries. Thus, when David Solomon of Qobuz began one of our interactions with, "Have you been to the room that's premiering the GaN (gallium nitride) tubed components?" I asked him to tell me more. David followed with something like, "I couldn't figure out how anyone could have possibly incorporated GaN class-D power technology into KT150, K88, and K120 GaNTubes™ until the guy showed the 'tubes' to me." That's when I knew I had to visit.

Nor did Solomon stop praising AGD's equipment and sound after we met. During my visit to the room, he showed up with two of his buddies so that they, too, could marvel at the US-designed and crafted inventions of Alberto Guerra (translated into English as "Albert War.")

AGD Productions, Inc paired its AGD Gran Vivace monoblocks ($18,500/pair) and Andante Pre-DAC streamer Phono ($12,500) with Allen Sides' Ocean Way Audio Eureka loudspeakers ($12,000/pair with stands and high-gloss finish as shown, or $7000/pair for basic finish with stands). Besides cabling and speaker stands, that was it.

But what a sound! From the sweet spot in the nearfield, soundstaging was nothing short of fabulous-the soundstage was huge and remarkably deep-bass on Reference Recordings' justly fabled issue of Copland's Fanfare for the Common Man, performed by Eije Oue and the Minnesota Orchestra, was excellent, and highs were lively and colorful. At first, I thought the sound a mite warm, but the more I listened, the more that initial impression was replaced by awe at the smoothness and beauty of the presentation. Anyone who has ever written off class-D technology as lacking in color must hear these components.

In the hope that John Atkinson (who's posting these reports) will amend my words if this GaN newbie gets it wrong, a GaN device can switch much faster than a silicon MOSFET transistor and addresses the slow switching issue that can be a problem with class-D. Guerra claims a 768kHz switching frequency and >92% efficiency for an amplifier using GaNTubes, which stay quite cool. The tubes are replaceable and have been upgraded twice since Guerra introduced his first components in 2018.

AGD's literature says that the 22lb monoblock's maximum output power is 200Wpc into 4 ohms at 0.1% THD+N, 1kHz, and the tube's bandwidth is 10Hz–100kHz ±3dB. He also claims 48,000µF of reservoir capacitance "and the fastest slew rate" with the "seamless ability to drive any loudspeakers." With both single-ended and fully balanced XLR inputs, the monoblock is crafted from a single aluminum billet.

Would I love to review these monoblocks with my Wilson Alexia 2 loudspeakers and other reference components? Is the Pope Catholic?

remlab's picture

..but an 8" mated to a 1"? Must have a really low crossover point

thatguy's picture

The GaN amps have interested me for awhile and as an owner of multiple tube amps I am a tube fan but I just don't see a reason to try to make a class D look like a tube. Tube pins need maintenance and are required since tubes are wear items; but here they are putting a potentially weak connection in a spot where it doesn't need to be. And the tube fan in me finds it a bit off to call these 'tubes' since they don't require the glass or a vacuum to function.

I guess it will get them attention that they wouldn't otherwise but it sounds like the unique position of being both a great amplifier and a gimmick at the same time.

daveyf's picture

I went into this room and asked the rep ( a lady) why the amps were mounted on top of the vibrating speakers...she told me that ladies like it that way?? Looks more aesthetically correct to them. We live and learn..;0)

Glad JVS liked the SQ, I thought it was one of the worst at the show! Minimal soundstage, poor driver integration, recessed highs, muddy bass and marginal resolution, I guess JVS YMMV.

hackmartian's picture

I was at THE Show as well and this was the best sound I experienced all day. Everything just sounded “right,” no matter the song, no matter the genre. The Eurekas deserve special praise, and this is now the system I dream of having in my home.