Still the 2N3053 sounds much louder. The loudspeaker used is the PHILIPS AD 5046N which is 800Ω. Many geniuses must have designed this remarkable speaker and its amazing Philips 9710AM full range driver (from 40Hz to 19KHz?) driver.
This may not be very fair to Electra II as it was designed to drive hi Z headphones.
Nevertheless a 10.5V voltage was connected to Electra II and output was taken from one channel and directly connected to the 800Ω PHILIPS AD 5046N. The sound was of very good quality but very quiet even when anode current was 3mA. The input potentiometer could be fully clockwise without distortion suggesting that more voltage may be needed to drive the 12K5 at higher power.
So perhaps an input transformer may be used.
And if a low Z speaker is to be used an output transformer may be used too.
So the schematic would be similar to the Pleiades V6 front end microphone amplifier but with higher voltages. An EF183 should be suitable by carefully connecting perhaps 47V and taking all safety precautions, or with many precautions a WE417.
Whereas the single 2N3053 is generously driven since it requires a bit of current which is more easily given by the 300Ω output impedance of the line output of the Sony CD Walkman used in these experiments.
And of course the point is that just a 2N3053 can give a world class sound just on its own.
No input transformer needed, no output transformer needed if the speaker is 800Ω.
The only other components are a battery, a biasing resistor form collector to base and a series input attenuating resistor.
The schematics of the refered circuits can be found on euroelectron blogspot by a Google search. They are open source as everything Pleiades.
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