Stereo Tube Amplifier


The circuit is simple, yet is capable of excellent performance. I designed it specifically for use as an amplifier for the digital sound card in my computer. Audio input can be from any two-channel line level device such as a television, CD player, or VCR. It is of the tube type, using only 5 tubes total with no more than about 45 Watts power consumption from the outlet. It uses 3 types of tube 1 5Y3 GT vacuum rectifier, 2 6SF5 GT high-mu triodes, and 2 6K6 power beam amplifiers. These are all full-size octal type tubes which are commonly available today for between $3-5 each.

Circuit diagram

Stereo Tube Amplifier-Circuit diagram


  • R1, R10, R13 2.2Meg Pot
  • R2 470K 1/2W Resistor
  • R3 1 Meg 1/2W Resistor
  • R4 220K 1/2W Resistor
  • R5 330 Ohm 2W Resistor
  • R6 220K 1/2W Resistor
  • R7 2.2Meg 1/2W Resistor
  • R8 1Meg 1/2W Resistor
  • R9 720 Ohm 20W Resistor
  • R11 33K 1/2W Resistor
  • R12 22K 1/2W Resistor
  • C1, C9 0.005uF 400V Capacitor
  • C2 0.05uF 600V Capacitor
  • C3 20uF 25V Electrolytic Capacitor
  • C4 0.01uF 400V Capacitor
  • C5 200uuF 400V Ceramic Disc Capacitor
  • C6, C7 15uF 450V Capacitor
  • C8 15uF 400V Capacitor
  • T1 117V Primary, 350VCT Secondary, 6.3V Secondary, 6.3V Secondary
  • T2 7600 Ohm Primary, 4 or 8 Ohm Secondary
  • SW1 SPST Switch
  • SP1, SP2 12" or smaller, 4 or 8 ohm speakers
  • MISC 5 tube sockets, 2 RCA jacks, PC board or chassis, wire, knobs, etc.


  • Email Weslee Kinsler with questions, comments, etc.
  • The 6V6 GT tube may be substituted for the 6K6 to lower power requirements.
  • C8 is for radio interference suppression and may be omitted.
  • The 5Y3 GT tube should be mounted in a vertical position and be well ventilated. The 6K6 and 6SF5 tubes can be mounted in any position.
  • Controls should have an audio taper.
  • The power supply portion of this unit may be used for anything requiring 290-320v DC up to about 3 amps.
author: Weslee Kinsler
circuit from