Stars - Dubstar

It was played at AB supermarket. They were very kind at headquarters to inform the title and artist of this nice song.

Using a MOSFET on these single transistor Pleiades powwer amplifiers?

At your risk. Please take all safety precautions. It looks tricky as by looking at some datasheets the on channel resistance is a fraction for an ohm. Typical current is a few amps. So it seems a step up output transformer is needed with a step up input transformer. Another option since depletion FETS do not need a say +4V at gate to turn on, is to use JFETS such as 2N3819. Many in parallel.

Increasing the power of the single transistor Pleiades BD139 amplifier at 12V only

At your risk. Please take all safety precautions. A multy turn ratio output transformer (it must be air gaped but so far tests have been donbe without introducinbg air gap) was created with secondary 9speaker side) inductance of about 40mH. Various collector volatges were tried including 12v, 24V, 36V, 48V. 24V sounded very nice, see also the Pleiades 2N3053 amplifier. The BD139 due to higher hFE is more sensitive needing less bias current and less music input voltage. Using the 5:1 ratio at Vb=12V requires about 27mA collector current for great class A operation (electrons flowing all time) sound. Rb=71Kohms. It sounds loud and clear. The schematic is just a single transistor with air gaped output transformer in the collector circuit, and just a bias resistor from collector to Base. The 2N3055 (not to be confused with 2N3053) sounded briliant as all the other mentioned transistors but it seems even more sensistive than 2N3053 and even BD139. But it blocked at Vb=48V for no reason known to me. It sung at Vb=24V. Higher Vb was tried with higher transformer ratios eg 7:1, 10:1, 13:1, 17:1. The laminations used were EI grand orient by Tranceria Ligure bought from Stefos in Athens.

How does the Pleiades DL93 single electron tube, 2 transformers and no other component audio power amplifier in class A schematic look like

At your risk. Please take all safety precautions. It looks very much like figures of patent US1349252A, Method of and Means for Utilizing thernionic currents - Harold D Harold.

Recording as many needed parts on the same analog magnetic recording track without generation loss

At your risk. See also a previous post. This is how Mike Oldfield created his Tubullar Bells demo by covering the erase head. Anyway at Pleiades lab the erase head of a Tascam Porta 03 cassette recorder has been disconected. Many singing parts were recorded on top of each other using just an SM58 at 24in above head connected to a Pleiades 175mH high pass filter. It is like painting on the same paper with different crayons. The 2nd pass partially blurs (only the very high frequencies are more affected) the 1st. The 3rd pass partrially blurs the 2nd and 1st. But the 4th, 5th,..., pass does not affect the 1st! For example a male singing voice immitated singing ducks of different age. Then the casstte recording of about 10 ducks in choir concert was played to Vicky's hi-fi system and she thought the recording had been done in a commercial good quality recording studio.

At the most unlikely places extraordinary things can be found

For example the Restaurant Samos by Olga and Fotis on Liosion street.