AGD Gran Vivace Mk II - GaNTube Monoblocks

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  • Impactful, organic sound from Class D via patented, industry leading GaN power technology.
  • The most advanced power stage in Hi-End Audio.
  • Gallium Nitride 600V MOSFET Power Stage
  • Up to 400W 4Ω (GaNTube 120KT model)
  • 800KHz PWM
  • ≥ 94% Efficiency
  • Noise floor at ≤ -130db
  • Fully protected (OVT, OVC, DC)
  • Gallium Nitride (GaN) MOSFET based power stage fully integrated in a KT120 Glass Tube (Octal Socket). Future upgradeable. 
  • GaN is ~10x faster that standard MOSFET.
  • 85W into 8ohms, doubling to 400W into 4ohms (>30A max current capability).
  • 40kOhm input impedance.
  • No oscillation during rise and fall time.
  • No undesired harmonic residuals or other artifacts are transferred to the output filter.
  • Extremely clean switching characteristic which are a unique feature of GaNTube power stages.


The AGD Gran Vivace Monoblock is the new addition to the AGD GanTubeTM Hi-End Power Amplifiers family. First to use the unique GaNTube™ technology with Gallium Nitride Power-Stage integrated into a Vacuum Tube, the AGD amplifiers are the most technologically advanced design available in the market today. The AGD “Gran Vivace” is rated 400W on 4ohm and it is characterized by an outstanding 50A peak output driving capability that will satisfy the most demanding loudspeakers and fill with musical sound pressure also the largest audio rooms. To achieve these performances, we have designed a new GaNTubeTM component, the AGD GaNTube KT120, larger and more powerful than its sibling AGD GaNTube KT88 MKii.

To achieve the highest-performance in audio reproduction, switching topologies must achieve nearly ideal switching waveforms, completely oscillation-free, to minimize distortion but most importantly, to preserve the harmonic content present in the original input signal and avoid the superimposition of any additional artifacts that alter the overall spectrum and the spatiality of the music reproduction. The Gallium Nitride power MOSFETS used in the GaNTubeTM power-stage simplifies this challenge through its ability to efficiently switch at much higher slew rates than any silicon-based power MOSFET, with almost perfect (book-like) behavior and oscillation free switching.

In this new AGD GaNTubeTM 120KT, a pair of powerful 600V rated Gallium-nitride power MOSFETs are at the core of the design. These new advanced components are the key to the reference level performance of the AGD “Gran Vivace” Monoblocks. Thanks to the improvement in components, and PCB layout (tested and introduced recently with the AGD GaNTubeTM KT88 MKii), we achieved the goal to operate also this much larger power-stage at 800kHz, with a direct and positive impact on the overall already outstanding sonic and musical performances.


Type Monoblocks
Class D
Technology GaNTube KT120
Power Output - p.c. 8ohm 200W
Power Output - p.c. 4ohm 400W
Input Impedence 40k ohms
Dynamic Range >130dB
Inputs 1x XLR, 1x RCA
Number of Chassis 2
Dimensions 190 x 140 x 190mm
Weight 5kg per unit


  • 2x mono blocks
  • 2x power cables
  • white gloves
  • all packed in a single, hard flight case 
AGD Gran Vivace Mk II - GaNTube Monoblocks
AGD Gran Vivace Mk II - GaNTube Monoblocks
AGD Gran Vivace Mk II - GaNTube Monoblocks
AGD Gran Vivace Mk II - GaNTube Monoblocks
AGD Gran Vivace Mk II - GaNTube Monoblocks
AGD Gran Vivace Mk II - GaNTube Monoblocks
AGD Gran Vivace Mk II - GaNTube Monoblocks
AGD Gran Vivace Mk II - GaNTube Monoblocks

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