Thursday, October 15, 2015

Pleiades Electra JFET Headphone Amplifier No Components

This is a source follower and the headphone coil (one for each ear channel) acts as the source resistor itself.


Pleiades Electra JFET Headphone Amplifier No Components


Some idea as on electron tube Pleiades Electra 1 and 2 where the headphone coil is the cathode resistor or the plate load resistor itself.


This is a brilliant idea that comes from the book Audio Amplifiers, Editor J.R.Davies, Data Publications, page 41, 2 - Transistor miniature AF amplifier. The AD140 power Germanium transistor has as load resistor the 15 ohms speaker itself. Class A, as electrons flow all the time, bias from collector to base, as simple as life can get, and amazing sound. The Idea also comes from another book by "uncle" Clive Sinclair, Transistor Audio Amplifier Manual. Hi impedance earpieces are used instead of collector load resistors, life is so beautiful.

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