6B4G Single Ended


Amplifier built with directly heated triode is perfection of sound and it`s considered to be an art of audio technique. Best known output tube is 2A3 directly heated triode. 6B4G belongs to family of 2A3 electron tubes with different base and filament voltage, all other characteristics are identical. As driver, triode strapped Siemens E280F HQ gold pin pentode was used. Output tube is 6B4G Electro Harmonix monoplate. Power supply is built around 5U4GB rectifier tube and CLC filter. To achieve better quality I used Nippon Chemicon electrolythics bypassed with MKP capacitors. Output transformers were wound on C-core. Amplifier’s wooden casing is handmade from painted oak wood. Complete electronics is fixed on 3mm steel plate. As the output power of this amplifier is small I would advice speakers of at least 90dB sensitivity.


  • Alps pot
  • Silver wiring
  • E280F; 6B4G; 5U4GB tubes
  • C-core output transformer
  • Auto bias
  • Nippon / MKP capacitors
  • 30 sec turn on HV timing
  • DC filament heating
  • 3,5W / 8Ohm
  • 0dB feedback