Stereo Power Amplifier GM70PA

Vacuum tube type stereo power amplifier with direct heating triode GM70. Plate voltage 1,050V, output 30W+30W. No-feedback technology creates a three-dimensional effect and a sense of presence, and expresses a clear sound.

Soviet triode GM70
It is equipped with the former Soviet GM70 with Pp=125W. With a plate voltage of 1,050V, 30W+30W (4 ohm) and 20W+20W (8 ohm) output, it can drive low efficiency speakers.

Two-stage configuration with C3g
It is equipped with the ultra-reliable C3g, developed by Deutsche Telekom for telephone repeaters. The thin grid lines and large distance between electrodes enable high linearity amplification. The C3g is soldered directly onto the board to reduce noise at the contact point.

Large Output Transformers
The large output transformer developed exclusively for this product is installed. Multi-layer sandwich winding drives both small and large signals over a wide bandwidth. Low winding resistance and drive capability, so it has a damping factor of more than 5 despite being a no-feedback amplifier.

Normal, Dual, Bridge Mode Switching
One more unit can be used as a bi-amp to drive the high and low frequencies. In bridge mode, the output can be driven by 1.5 to 2 times.

*Except in normal mode, it is valid for Lch/XLR inpu


Model GM70PA-G / GM70PA-C
Type Class-A Vacuum Tube Stereo Power Amplifier
Output Power [Normal, DualMono]

・30W+30W(4Ω, THD5%)

・20W+20W(8Ω, THD5%)


・60W(8Ω, THD5%)

・40W(4Ω, THD5%)

*The other than normal is valid for Lch/XLR input.

Frequency Response 20-30kHz -2dB/10W
THD [Normal, DualMono]






NFB None
Signal to Noise Ratio 90dB/1W(20-20kHz)
Crosstalk 40dB/1W(20-20kHz)
Input Sensitivity [Normal, DualMono]






Gain 21dB
Input Terminal UNBALANCED x1, BALANCED x1
Input Impedance 2.5kΩ 1kHz
Mode Switching By the rear rotary switch
Volume Adjustment None
Damping Factor 2.8(4Ω), 5.6(8Ω)
Power Supply AC100/120/200/240V, 50/60Hz
Power Consumption 400W
Dimensions 470W×201H×430Dmm *
Weight 27kg
Finishing Anodic Oxide Coating
Accessories AC Cords
Warranty Period 5 years(Excluding consumables)

* Knobs and terminals are not included.

  • The input impedance of this unit is 2.5kΩ. Please use a equipment with an output impedance of 500Ω or less.
  • The standard model is equipped with the GM70 graphite plate. (Model: GM70PA-G). A model with a copper plate (Model: GM70PA-C) is available as an option.
  • Do not touch the vacuum tube as it is hot and may cause burns.
  • Vacuum tubes are treated as consumables and are not covered by warranty.
  • Product appearance and specifications are subject to change without notice.


Inc 21% VAT Ex VAT
Stereo Power Amplifier € 25,410 € 21,000