Thursday, August 22, 2024

Tubes vs Transistors vs MOSFETs, is there an audible difference?

At your risk. Please take all safety precautions. The title is paraphrasing the beatiful article by|Russel O. Hamm... The Pleiades 2N3053 power amplifier in class A consists of just one 2N3053 transistor, a battery, a fuse, an output transformer, a bias resistor, and an input coupling capacitor. The Pleiades DL94 is almost the same circuit with a DL94 electron tube. It is about to be further simplified by building another one with no capacitors or resistors. Just an input ransformer, an electron tube, an output transformer, a Va battery, a Vb battery and a Vc battery for bias connected to the input transformer. The bipolar transistor 2N3053 may be further simplifier by including an input transformer and a similar kind of bias arrangement trough this input transformer. The input transformer is very important for the electron tube version as it provides x12 voltage gain, so that a driver electron tube is not needed and the whole job feeding the loudspeaker with music through the output transformer is done by just one electron tube. While explaining this to Panos, he sugested|i read Susan Parker's post on diyaudio on her push-pull, input transformer - MOSFET - Output transformer amplifier. Inspired by them why not making a Pleiades single ended MOSFET class A amplifier. Just an input transformer, a MOSFET and an output transformer. If the MOSFET is an enhancement type it may be possible to do away with external bias? But first trials will be with an IRF740 depletion type MOSFET given to me by Grigoris. The bipolar, electron tube versions sound so beatiful. How would all 3 types of amplifier, bipolar, electron tube, MOSFET compare on such similar, minimum component possible environment?

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