This item is provided only by "full kit" form. Moderate soldering skill is required for completion. Additional manual for assembling is supplied in this item.

What is it?

Vacuum tube headphone amplifier with USB DAC. Power is fully supplied by USB. Optional circuit modification enables iPhone 6s driving.

Why did you make it?

I have made lots of Nutube related items, and got to know a 1950's tube 3A5 has a lot of similarity including its structure and operation. Comparing its cost, Nutube is $50 and 3A5 (with guarantee) is around $10 even in 21st century. I made a small modification of the circuit and confirmed 3A5 can work just like Nutube. No way to avoid one!

What makes it special?

• This is a tube but no need for extra power supply except for USB bus power. Embedded voltage booster generates the voltage required for 3A5 operation.

• Onboard USB DAC (TI PCM2704C) provides simple but high-performance operation. The resolution/sampling frequency are 16bit/48kHz (not high resolution one. If you prefer Hi-res, please refer to "ULTRA Tube Amplifier" of my item.)

• Super low price. Just $50 includes everything except for headphone and USB cable!

• If you put small modification (details is available in the instruction manual of this item), this headphone amplifier can work with iPhone 6s. I have not checked its operation rest of the iPhone (and Android) but if you are 6s user, it should be worth to try.

• The tube is made in 1950's and we sometimes have a faulty (dead) tube. Before shipping, all of the tubes are tested and only test-passed one can be your item!

This item is provided only by "full kit" form. Moderate soldering skills are required for completion. Additional manual for assembling is supplied in this item.