2A3 SE Single-end Tube Amplifier 5W+5W Kit (Stereo)

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Quick Details
Brand Name:
Analog Metric
Model Number:
2A3 SE
Place of Origin:
Hong Kong


Vacuum Tubes: two 2A3 and two 6SN7
5W to 8Ohms speaker for each channel
class A power amplifier which has high linearity


This 2A3 SE valve amplifier is a class A power amplifier which has high linearity and low distortion, are capable to delivery 5W to 8Ω speaker for each channel. The first stage is SRPP constructed by 6SN7 twin-triode tubes and the final stage is a common-cathode 2A3 tube. The B+ power and two filament voltages are supplied by one CM400 Zener voltage regulator and one LV30P-5A voltage regulator.




  • Vacuum Tubes: two 2A3 and two 6SN7
  • Input sensitivity: 3.9V
  • Input impedance: 90KΩ
  • Voltage gain: 1.75dB
  • Gain flatness <0.9dB for 20-20kHz
  • 3-db Bandwidth: 31.2kHz
  • S/N Ratio: 98dB (5W@8 Ω)


  • Single-end output transformer S15 15W

   Primary impedance: 2.5kΩ

   Secondary impedance: 4/8/16Ω

  • Maximum output power: 5W for each channel.
  • Use with the CM400 Zener voltage regulator.
  • Symmetrical layout design in signal paths for both channels.
  • Dedicated ground and power rails layout design.
  • Two large reservoir decoupling capacitors for power rails.
  • Power requirements: one 240V AC (300mA), two 6.3V AC (1.5A), two 2.5V AC (2.5A)
  • PCB dimension: 130mm (W) x 165mm (L) for 2A3 SE PCB

                             98mm (W) x 130mm (L) for CM400 PCB

  • PCB thickness: 2.4mm, double layer, 2oz copper.