Finally, headphiles' dream has come true in the form of the TTVJ Millett Hybrid Amp. Todd, the vinyl junkie and well know Mr. Millet who also helped design the Headroom tube head amp, has put together a one-of-a-kind hybrid amp. It's the world's first battery-powered tube headphone amplifier.
The size is on par with your pocket. The head amp uses tubes at the first amplifier stage, which is later amplified by the solid stage. Inside that small box, there's really no place for common tubes. So, it was important to use some special miniaturized vacuum tubes that were used and designed in the past vintage years for hearing aids and many “pocket” radios. Normal tubes use at least three or four watts of power, and sometimes more, but these small tubes only draw 15 milliwatts. This should allow the amp to work 40 hours nonstop after just one charge of the battery! Charging the battery takes anywhere between 1-2 hours.
The amp uses a built-in lithium battery, the same battery used in many modern devices like mobile phones and digital cameras that recharge in only an hour or two. A higher voltage and a voltage (to power the tubes and the solid-state output buffers) are generated by a very particular power supply circuit. The creators of this amazing little amp took great measures to ensure the sonic characteristics and power supplies would perform efficiently, so as to have an optimized battery life.
This portable head amp is capable of loading 8 volts RMS into headphones, which should happily drive both high and low-impedances. Basically, it can drive pretty much everything. It's priced at around $460. Grab yours directly from Todd’s site: http://www.toddthevinyljunkie.com