DC Entries: Last Batch

Here’s the final batch of entries we received and considered for the Design Challenge.

[Chris] sent in a stereo amplifier (watch out for pop-ups) designed for iPods (or similar) using LM386 amps and a minimal parts count.

[Fabian] submitted this excellent tube amp. It’s based on the ECC83/12AX7 tube, and runs off a mere 12-14VAC.

[Edgar] sent in this combination PIC/AVR programmer.

Finally, we’ve got a simple PIC/EEPROM programmer by [Ian]. (view the unzipped version here)


  1. ian says:

    I also made an instructable for my project so it is easier to see:


  2. CHAD says:

    looks like the first on in this list (chris — and his amp ) have gone over his limit can comeone link this of cache this



  3. CHAD says:

    forgot to add the tube preamp is badd a$$ cool one !!!


  4. joelanders says:

    i reeeally like the tube preamp. its awesome to see classic hardware being used instead of some $1.19 ic from radio shack.

  5. Monkey says:

    Cool stuff. The stereo amp link is down, seems a bandwidth problem.

    I wish I would have put in an entry… maybe next time.

  6. lonasindi says:

    I would love a better write-up on the tube amp, I don’t have a lot of experience building stuff like that, and tubes are heavy stuff.

  7. Alan says:

    The tube amp is very interesting, it would have been nice to see the finished product though (or at least a 3D model)

    Congrats to all the participants, each one was well done.

  8. fabian says:

    hi, i was the one who posted the tube amp. it’s pretty easy to build since it needs no biasing or adjustments. But I can write a more detailed instruction for building and tweaking the amp. It will take me a few days, however…

  9. Edgar says:

    I did a page for my project the AVR/PIC Programmer, it is located here: http://www.ebarranco.com/had06/

  10. Andrew says:

    there were only four entries?

  11. fabian says:

    @andrew: no, there’s lots more; check out

  12. james says:

    awesome tube amp. but i’m having some trouble getting started.

    does anyone have a part list for digi-key or other distributor? im having trouble find parts for this sweet tube amp.

  13. fabian says:

    Hi, I only have a partslist for a German distributor. But I might help you finding the parts if you want. Write me to fabian [at] tubedogg [dot] de.

  14. person says:

    These contest entries have been great ideas.
    I just have one question.
    What are you guys using to read your .sch files?

  15. Aaron says:

    Thanks to Chris for adding the .ISO files. I don’t really want or need one but hey, I’m sure I have the parts laying around and if the work is already done for me, why not. Thanks!

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