The trick may be soft clipping the live music signal before it gets to an op amps or to A to D converter where it will be possibly abruptly and unmusically clipped.
(A music signal has a tremendous dynamic range. Only 20dB difference means x100 voltage. If a live signal is sent to an op amp and we do not want it to be clipped the average volume would have to be reduced too low. So it will sound too weak).
Could gradual harmonically enhancing restriction of the signal by soft clipping be done by just one electron tube, a microphone and an a very high ratio Pleiades for example input transformer?
Could it be that a low load resistor (RL) and a bias close to 0 volts does the trick?
So that the signal is conditioned with just one class A (electrons flowing all the time) amplification stage instead of many electron tubes in preamplifiers, compressors etc?
A very low voltage anode supply such as 3 volts is used on some Pleiades V series preamps. Would this be enough or less is needed?
Maybe a good time to look at electron tube load lines. RL changes the slope of the load line etc, see reference.
The Pleiades input transformer can be made with the extreme inductance index Magnetec Nanoperm ring tape wound Nanocrystalinne core. Suitable types can be Magnetec 073, 070 etc.
References:
Tubes vs Transistors is there an audible difference? - Russel O. Hamm - JAES
Electronics, a systems approach - Neil Storey
Applied Electronics - T.S.Gray - M.I.T.
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