A Sowter SK05s output transformer was connected to the 2N3053 transistor so that an ordinary 8Ω speaker would become high impedance.
A SONY APM-078 6Ω small 2 way speaker was connected. Inside it has a single capacitor in series with the paper small speaker tweeter.
When supplying by 12V there was some distortion. When supplying with 24V (2x12V batteries, attention to fuse use and all other precautions) the sound was very nice and comparable in loudness to the PHILIPS AD5046N when supplied with 12V.
The biasing variable resistor (100kΩ potentiometer) from collector to base was set to 100KΩ.
It has to be noted that when the AD5046n speaker terminal is supplied with 12V, about 5.8V arrive at the collector due to the voltage drop of the 800Ω voice coil.
The voltage drop of an output trasformer should be much less.
Yet the PHILIPS AD5046N now back to 12V supply still sounds louder. Of course because of its sensitivity. Additionally perhaps due to burn in of the transistor from the higher (about 20mA at 24V power). Or because of self cleaning of contracts in the alligator small cable clips. The Pleiades 2N3053 millipower amplifier is at an experimental stage.
Sounding so nice.
Reference:
http://euroelectron.blogspot.gr/2018/03/madonnas-voice-coming-from-point-source.html
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