The Tube Head preamp is using a single 5670/2C51 tube in a modified LC-1 auto bias adjusting hybrid circuitry. There is no need to adjust the bias or try to match the tubes.

The Tube Head is a "dual-chassis double-decker" design with a separate power supply linked by an external cable. There are two set of inputs and one set of output. The volume control can be switched to either Shunt type or Series type providing different sound signature.

Specifications:

 6Hz - 100kHz : -1dB at 600 ohms loading, low noise
 
 Tube Buffer 5670 (2C51). DC amp. coupling capacitor less
 
 Opamps are exchangeable (default setting OPA2604), you can tune tone yourself
 
 110V/220VAC switchable
 
 Size: 11 x 8 x 10 cm
 
 Weight: 960 gram