At your risk. All voltage, current, hearing safety precautions should be followed. Especially when listening through headphones, SPLs (sound presure level) should be very low or hearing may be irreversibly damaged. Headphones should never be worn while they are connected to transformerless amplifiers or while switching on, off. Headphones should never be worn while experimenting. Volume should always be kept down. More than say 5mA quiescent current may damage headphones. Etc...
It looks possible. It is very easy to get just a few milliamperes from the WE417A electron tube. It may be possible for this to happen at just a couple of dozens volts anode potential.
A transformerless power amplifier should be possible driving directly high impedance headphones. For example the say 2KΩ output impedance of the WE417A electron tube should easily drive the Sennheiser HD580 300Ω impedance at nice quasi constant current, voltage condition. A schematic such as or similar to Pleiades Electra 2 (without Vb on grid) or Pleiades V6 with Pleiades pull up bias may do the trick. Pull up bias from anode to grid though a high megohm resistor should allow operation at just very few dozens volts of anode potential. Higher potential would lead to much a higher power output which could be very dangerous for hearing. All known safety preacausions should be followed.
Such amplifiers are operating in class A (electrons flowing all the time). In this case it means electrons flowing hrough the WE417A anode, headphones and back to cathode all the time. The modulation of this flow is the music signal itself. It can be visualized as electrons dance to the misic. It's their party.
It's my Party - Leslie Gore
https://m.youtube.com/watch?v=V6Uo1nNt6LU#fauxfullscreen
Produced by Quincy Jones, recorded by Phil Ramone
(Voice double tracked by magnetic tape recording sound on sound)
(If memory is correct there is a section on the Making Records - Phil Ramone book mentioning this song.)
How would she sound like?
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