The Pleiades Kit

It would be nice if a Pleiades kit existed with a breadboard or springs for quickly connecting components.


It could have an XLR female input at the left and an XLR male output at the right.


The Pleiades V6 battery powered electron tube microphone head pre amplifier could be built.


Or the Pleiades K117 JFET head microphone pre amplifier.


Or the Pleides 2N3053 power amplifier in class A too (electrons flowing all the time). With a very small voltage it can drive studio hi Z headphones. With a higher voltage it can directly drive a hi Z loudspeaker such as the brilliant Philips AD5046N.


Or the Pleiades Electra II or III headphone amplifier with only 2 tubes, one per channel, and almost nothing else.


In fact many of the Pleiades circuits were made this way. (Or just crocodile cable clips for the 2N3053 for example). Attention to safety, a fuse should always be in series with the battery terminals.


The Pleiades Electra and Pleiades V6 were built on breadboard or project board.


Breadboards from K and H products, Taiwan were used. Mostly the small one KH-102. The bigger GL No.12 looks very interesting too.


Octal bases for transformers, noval base for the electron tube were soldered to all their pins with the right length of copper wire. So then the base would plug to flush with the project board and make life very easy. Attention, these circuits even if they may use electron tubes use just no more than 3 to 12 volts which can be considered safe. They sound great with very low noise and are electrically safe. Nevertheless it is very important that batteries are used in series with a fuse. Operation with low voltage is possible by neutralizing the space charge by a high Megohm resistor from anode to grid, see references.


At the moment the Pleiades 2N3053 is being connected up to the larger Pro-ject board in order to attempt to connect the Sennheiser HD 580 headphones with the amplifier powered by just a 1.5V battery. Attention also to using headphones. They should never be worn while experimenting and intensity should always be kept low to protect our precious hearing.


References:


On preserving transconuctance of an electron tube at low anode potential - euroelectron


Operating Features of the Audion - E. H. Armostrong