AGD AUDION Monoblock


Design Philosophy

“The new AGD “THE AUDION” is one of the most Compact Amplifier Design in Hi-End Audio. “THE AUDION” Monoblock uses the unique GaNTube™ technology with Gallium Nitride MOSFET based Power-Stage, fully enclosed in a Glass Tube. The Gallium Nitride Power MOSFETS, are the unique technology design advantage of AGD Productions, and are the key to the reference level performance of all AGD amplifiers. With the seamless ability to drive any load, “THE AUDION” can deliver an unmatched sonic experience that only SET designs have been able to provide so far.

With 170W of power capability, the fastest voltage slew-rate, and with 20,000µF of super audio grade capacitor reservoir, “THE AUDION” is uniquely capable of sustaining the deepest bass punches while delivering the finest harmonic content of any vocal and musical instruments ensemble. Crafted in a minimalistic ultra-compact solid aluminum case, “THE AUDION” has one single ended and one full balanced XLR inputs, (40kOhm std. and 600ohm upon request), enabling a perfect match with any direct source units (DAC) or preamplifiers in the market.

Design Philosophy

The AUDION Monoblock amplifiers are build around the same output power stage used in the AGD Vicace. To achieve the highest-performance in audio reproduction, THE AUDION mono-block employs the same fundamental technology pioneered by the AGD Vivace design. As with the AGD Vivace, also in THE AUDION design we were able to achieve nearly ideal switching waveforms, completely oscillation-free

Thus, preserving 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.


THD+N @ 0db output, 4ohm, 1kHz

XLR Input (40kohm input impedance)


THD+N @ 0db output, 4ohm, 1kHz

RCA Input (40kohm input impedance)

PWM Frequency waveform at VS switching point.

Voltage rise time waveform.

Switching voltage at VS point  ( + 4000V/μs)

Voltage fall time waveform.

Switching voltage at VS point  (- 4000V/μs)

100 Years of AUDION Evolution 1918 ~2018

The AUDION Tube 1906
(Triode from 1918)

Lee de Forest’s triode tube (Audion) from 1906.

  • Top metal electrode is the plate.
  • Grid is the bent metal wire partly visible.

AGD “THE AUDION” GaNTubeTM MonoBlock 2018

  • The most advanced power stage in Hi-End Audio.
  • Gallium Nitride MOSFET based power stage.
  • Fully integrated in a Glass Tube (Octal Socket)
  • 170W, 4ohm (>30A max current capability).
  • 400KHz PWM.
  • 40kOhm input impedance.
  • <-130db noise floor.

Main Features & Characteristics:

1. Power Entry Module
2. Fuse Holder
3. Input Voltage Selector
4. ON-OFF Switch
7. Analog Input Selector Switch
8. RCA Single-ended analog input
9. XLR Balanced analog input
Maximum Output Power at 0.1% THD+N, 1KHz, 4Ω.170W
THD+N 10W/1KHz<0.005%
Output Power at 0.01% THD+N, 20Hz÷20KHz, 8Ω85W
Bandwidth ±3dB5Hz÷100KHz
Input Impedance40kohm (600ohm upon request)
Noise (A-weighted)< -130db
GaNTubeTM PWM Frequency400kHz std.
Weight5lbs (2.5kg)
Input Voltage110-240V (user selectable)