CS Port GM70 ClassA Stereo Power Amplifier

Matej Isak

Another addition to the CS Port impressive portfolio is CS Port GM70 ClassA Stereo Power Amplifier, based on the GM70 tube. “This is a full-fledged product with a plate voltage of 1,050V applied for low distortion rate operation and output of 30W+30W drive. In addition, using a switching power supply even at a high voltage of 1,050V realizes safety, light weight, and compact size. Non-feedback creates a three-dimensional and realistic feeling and creates a clear sound.”

Installation of the former Soviet triode GM70

It is bigger than Pp=125W and 845 (Pp=100W) in one cycle, and is equipped with a low-impedance, direct-heat triode GM70, with outputs of 30W+30W (4Ω) and 20W+20W (8Ω), and it can also drive mainstream low-efficiency speakers in recent years.
Equipped with ultra-high reliability tube C3g
To Deutsche Telekom’s telephone relay Developed Equipped with ultra-high reliability 5-electrode tube C3g. High linearity voltage amplification is possible because the grid line is thin and the distance between electrodes is large. This unit does not use a socket, but solders directly to the board to suppress noise generation at the contact point.
Large output transformer with sufficient margin

Equipped with a large-output transformer developed for GM70PA. Multi-layer sandwich winding drives a wide band from minute to large signals. The low winding resistance and drive capability provide a large damping factor of 5 or more as a feedback-free amplifier, securely driving the low frequencies.
Normal, Dual, Bridge Mode Switching

You can use it as a stereo amplifier with a NormalMode, and as a bi-amp with an additional unit that drives the high and low frequencies with a DualMonoMode. The BridgeMode also allows outputs to be doubled from 1.5.
* Other than NormalMode, it is enabled when Lch/XLR is inputted.
Specification
  • Model GM70PA
  • Method Input transformer built-in Class A operation vacuum tube type stereo power amplifier
  • Configuration Input transformer-C3g 3connection-FET driver-GM70-output transformer
  • Output
  • Normal, DualMonoMode…30W+30W(4Ω, THD 5%)
  • Normal, DualMonoMode…20W+20W(8Ω, THD 5%)
  • BridgeMode…60W(8Ω, THD 5%)
  • BridgeMode…40W(4Ω, THD 5%)
  • Frequency Response 20 – 30kHz -2dB / 10W
  • Total harmonics distortion
  • Normal, DualMonoMode…0.7% / 10W
  • Normal, DualMonoMode…0.2% / 1W
  • BridgeMode…0.5% / 10W
  • BridgeMode…0.1% / 1W
  • NFB None
  • Signal-to-noise ratio 90dB / 1W(20-20kHz)
  • Crosstalk 40dB / 1W(20-20kHz)
  • Input sensitivity
  • Normal, DualMonoMode…1V / 30W(4Ω)
  • Normal, DualMonoMode…1V / 20W(8Ω)
  • BridgeMode…1V / 60W(8Ω)
  • BridgeMode…1V / 40W(4Ω)
  • GAIN 21dB
  • Input connection One RCA and one XLR system
  • Input impedance 2.5kΩ 1kHz
  • Mode switching By the rear rotary switch
  • Volume adjustment None
  • Damping factor
  • Normal, DualMonoMode…2.8(4Ω), 5.6(8Ω)
  • Power supply AC100 / 120 / 200 / 240V, 50 / 60Hz
  • Power consumption 400W
  • Size 470W × 201H × 430D Knob,terminal not included
  • Weight 27kg

Finish: Silver alumite and bake coating
*The input impedance of this unit is 2.5kΩ. Drive with a device with an output impedance of 500Ω or less.
*Carbon plate GM70 is mounted for normal products, but metal plates are also available as an option. Please inquire about the price.
*Changes in specifications, design, design, price, etc. may be made without prior notice.