Project files: Szekeres VE headphone buffer

What is it?
This is a board for my version of Richard Murdey’s Szekeres VE (for “virtual engine”) buffer. This design is based on the original buffer concept by Greg Szekeres published at headwize a long time ago (c. 2002). The Szekeres buffer was one of the original headwize designs that I was very interested in when I started building amps due to its simplicity, but I never really got round to it. When I stumbled upon Richard’s revised version I had to try it – just to see if it was as good as I had imagined all those years ago (well, almost 🙂 ) Oh, and be sure to check out Richard’s site for some other very interesting DIY designs as well.

How big is the board?
The board measures 3.925″x1.95″ (just under 10×5 cm.), so just small enough for a 5×10 cm board service at itead.

What is the status of the board?
The board is in version 1.1. I have tested v1.0 and made a couple of alterations to the board as there were some minor space-issues here and there, but nothing serious.

Does it use any special/expensive/hard-to-find parts?
Yes. The power resistors are TO-220 types, Caddock MP-915 or MP-930 or equivalent and they are quite expensive. The FETs are cheap but need to be matched, so buy 10 pcs. or so. The heat sinks are Fischer SK129 types (or any one of many equivalents)

Anything else I need to know?

  • The layout is pretty tight so the mounting sequence is quite important, especially if using heat sinks taller than 25mm. Start with mounting the small resistors on the board. Then loosely assemble FETs, power resistors and heatsinks before mounting them one by one on the PCB. The mounting sequence should be to first to solder the heat sink pins and then the FET/resistor pins in place before tightening the FET mounting screws. Then move on to the next heat sink.
  • There is only room for small capacitors on the board so a regulated PSU is recommended (several options available from this site 😉 )
  • The FETs are the IRF510 types recommended in the article. The FETs need to be matched as described in the article as there is no way to null DC offset.

Download design files here

Related information:
Note: Always read the “intro post” for additional important information about my designs.
Refer to the RJM audio site for BoM and information of component selection.



3 Responses to Project files: Szekeres VE headphone buffer

  1. says:

    I like this article, I have reblogged this one, thanks for posting

  2. Pingback: J-Mo buffer/headphone amp | theslowdiyer

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