Is a vacuum tube electric guitar stomp box or DI possible with an AA 1 2V battery

Possibly so.


If a standard Hammond aluminum box can fit a Bulgin AA battery holder...


If a Nuvistor electron tube such as 2DV4, 2DS4, 2CW4 is used. Underheating is good especially when operating with small anode voltage as it still provides space charge ie lack of shot noise. Llewellyn]. Also the low temperature has beneficial effects on noise. [see also Pearson], [Neumann U47 schematic], [Pleiades V6 schematic].


If Pleiades bias or pull up bias is used. For example a 1.8MΩ resistor from anode to grid. The grid is already too heavily negatively biased by the missing electrons from the cathode temperature emission or thermionic emission. The Rag resitor will make the grid less negative with respect to cathode, liberating electrons and making anode current possible even at 1.3V anode potential. See precious posts on Nuvistor 7586 and EF183. Even the presence of an open (unconnected) grid restricts the flow of electrons [Armstrong].


The output transformer can be a 1:1 as impedance reduction might not be needed at high Z guitar circuits.


The electric bass or electric guitar signal can be applied to the grid through a coupling capacitor. Like the following Pleiadss V6 mic booster circuit but without the input transformer. A shunt or in parallel Pleiades inductor or R,L filter can be directly connected to the pickup to produce correct bass to listener's brain [Lowe, Morgan].






If a DI output is required then the output transformer can have a lower winding turns secondary for low impedance and of course balanced out. A high Z out can also be taken by connecting a coupling capacitor to anode loaded by the primary of the transformer. Anything is possible, RC coupling (with some reduction to the anode voltage), transformer coupling, impedance (inductor in the anode circuit) coupling etc.


See also the Pleiades V1 pre-amplifier (RC coupled anode follower) with the CV2269 electron tube operating with just an AAA 1.2V battery. Current consumption is only 13mA due to the ridiculously low heater current of the CV2269 electrometer electron tube.


How does the Pleiades V1, possibly worlds smallest and less power consuming vacuum tube pre-amplifier sounds like?
Listen to Tezcatlipoca, possibly world's first track produced with sun energy only - renewablemusic channel - YouTube
https://m.youtube.com/watch?v=2RD02ATDPAk


References:


The Pleiades Bias - euroelectron


Operating Features of the Audion - E. H. Armstrong


A study of Noise in Vacuum Tubes and Attached Circuits - F. B. Llewellyn - Bell Telephone Laboratories


Fluctuation Noise in Vacuum Tubes - G. L. Pearson - Physics sept 1934


Flat frequency response from producer's brain, Sound Picture Recording and Reproducing Characteristics - D. P. Lowe, K. F. Morgan - J.S.M.P.E