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Monday, June 6, 2016

D3a Differential Phono Preamplifier, Part 1


After the great results I got from the EC8020 differential phono stage, two more versions of that circuit will be built.

One will be a scaled up version with all silver transformers, but before that I am building it with the more affordable and less scarce D3a tubes.

It will share the same circuit concept but with transformers and chokes adapted for the operating conditions of the D3a which will be triode wired.

The same chassis layout is used and the same vibration damped mounting of each tube socket.

8 D3a tubes arranged in two rows.

Transformer coupled and fully balanced throughout and of course with 600 Ohm LCR RIAA EQ.

Stay tuned for updates on this new phono!

Best regards



  1. Which LCR module will you use? Have you compared using just silver outputs to silver outputs and silver chokes? Seems like the silver chokes in the power supply or the like would have little benefit. In the signal path, I totally understand it.

    1. Hi!
      Please understand that I am not going to share technical details about this phono stage as it is part of the top line which will not be available as kits. This version will be entirely with copper transformers and chokes.

      best regards