Saturday, September 30, 2017

Some earlier Pleiades Electron Tube Amplifiers


Names have to given to these too in the chronological order they were made. For example V-6 older than V-4


This post will be a rough estimate.


If memory is correct the first Pleiades electron tube amplifier was a single ended power amplifier based in the PCL86 triode pentode in the same glass envelope. The design was based on the application schematic of the excellent French radio tubes data book. The transformer used was ordered from Hammond in U.S. The treble and mid juice of this amp is excellent. It can be heard on the organ sound driving a full range vintage speaker hung and rotated from the ceiling to give the Doppler Leslie effect. The vid is titled Mystery on YouTube Chanel renewablemusic. The only mics in the room were Coles 4038 driving a Pleiades E88CC 2 stage long tailed pair. Sowter input and output transformers. 2 for stereo. Then if  memory is correct the output was attenuated and EMI RS61s were driven and then driving the A to D converter of a modified Philips CD-R. Unfortunately the image quality given to the vid was bad and YouTube treated the sound too as such. The file used may had been MP3. The mics were hung from the ceiling. Unfortunately there was no acoustic treatment for the room.


Other Pleiades amps in almost random order:


300B single ended class A. Final year engineering electronics project at Warwick University. It is thanks to professor Flower, head of engineering and his kind secretary who booked the appointment that this project could begin as no lecturer was happy taking in a project on electron tubes in 1994.


Other Pleiades Amps:


Cascode mic preamp with nuvistors.


Small simple ECC83 stages.


Smaller ECC86 stages powered by 6V.
























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