This is a portable headphone amplifier with a hybrid configuration - 2 subminiature tubes for input and OP-amp for output. Enrich your life with smooth and mellow sound anywhere!

[Feature]
- Battery-operated vacuum tube Raytheon 6418 Low consumption current and almost no heat generation so that there is no problem if the holes on the chassis are sealed.
- Minimized microphonic noise
Microphonic noise, often controversial in tube portable amp, is minimized by setting the vacuum tubes higher than the PCB.
- Unlikely to usual vacuum tube amplifier, TU-HP01 starts up only in a few second after the power is turned ON.
- Exchangeable OP-amp
2 OP-amps, JRC "MUSES8820" and BurrBrown "OPA2604" are included as a standard. ("MUSES8820" is mounted by default.) In addition, users can exchange it with many other commercially-available OP-amps to enjoy the difference in sound.
- Dual supply for OP-amp
No capacitor is required to the headphone output.
- Gain SW
Users can select either high or low according to the input level.
- Almost no pop noise upon power ON.