DISCLAIMER: Vacuum tube circuits work with dangerously high voltages. Do not attempt to build circuits presented on this site if you do not have the required experience and skills to work with such voltages. I assume no responsibility whatsoever for any damage caused by the usage of my circuits.

All rights of photos and text reserved. Usage of photos or text from my blog on other websites or for any other purpose only with prior permission. If you want to use any material from my blog please contact me by email.

Sunday, April 23, 2017

The 6 Channel Field Coil Supply


Some photos of a field coil power supply which has been finished recently.

It is meant to supply a pair of speakers with 3 field coil drivers per side.

All in one chassis.

Completely passive choke filtered supplies, independent for each driver.

Voltages can be adjusted in 5% steps with a common set of switches per section (bass, midrange and tweeter). Digital meters monitor voltage and current of each of the 6 independent supplies.

Adjustment is done by selection of different primary and secondary taps on the power transformers to avoid any regulation circuitry.

LCLC filtering of each of the 6 voltages, so 12 chokes in total.

The finished unit weighs over 50kg!

Best regards



  1. or hot?
    There are no Kühlschlitze on top!!!