Two-Way Bi-Amp
A 300B for the highs and EL156 push-pull for the lows, with the crossover built in.
Inspired by the work of Susumu Sakuma, this amplifier drives a two-way speaker with two amplifiers on one chassis. A 300B single-ended stage plays the high range and an EL156 push-pull stage plays the low range. The frequency divider sits inside the amplifier, so the speaker's passive crossover can be removed. Each amp has its own tube rectifier and interstage coupling, with Tamura transformers throughout.
- High range
- 300B single-ended
- Low range
- EL156 push-pull
- Crossover
- Built-in divider, set to your speaker
- Coupling
- Interstage transformers in both amps
- Rectifier
- Separate tube rectifier per amplifier
- Transformers
- Tamura, custom ISO power transformer
Includes setup notes for your speaker.
From your room to your rack
01Your room
We start with your speakers, your room and the music you play, then draw the circuit around them.
02Chassis and wood
Panels are cut, drilled and engraved here, and the frame is made from Thai hardwood.
03Hand-wiring
Every joint is wired and soldered by hand, point to point. You get photos as it comes together.
04Burn-in and listening
Each build runs for days on the bench and is measured and listened to before it ships.
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