Is it possible to make a battery powered Project T1 BT turntable?

elf deflating matress more comfortable?

At your risk. After sleeping on a compromised thermarest neo air x-therm, body seemed more comfortably feeling in the morning.

Using a direct heater electron tube as space charge tetrode for driving hi Z headphones from the anode powered with a few volts?

At your risk. After re-reading One Tube set Works on Flashlight cell article found on junkbox.com using 49 electron tube. How about tubes starting with 4 indicating 4 volt filament? These should be less energy consuming than Pleiades Electra 2. Why on universe should we expend energy in order to listen to music? Saw today a cat warming herself up under the winter sun.

Everything in music

The sensation of music depends on how far is the bass at any moment from the tonic. And then how far are notes from ,melodies existing at the same time, from any bass. (from a discussion with Vicky). (harmony notes can be chose from the series 1,3,5,7,9,11,13) Further reading: Bach Bass Rules - Bach, Niedt - PDF