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Monday, May 9, 2016

A 12AU7 Atop a Raspberry Pi


I don't know what to say.   One moment I find myself thinking that this could represent "the best of both worlds."   A minute later I'm thinking that this thing is a horrible chimera.  And it has a whiff of audio fool-ism about it, don't you think?  Will it work better with oxygen-free cables and gold-plated fuses? 

Still, overall -- pretty cool.


  1. It's all about the warm glow of the tubes and the slight 60 Hz hum which in known to enhance any content. Look for an old AM broadcast radio at a garage sale with a low level "phono" input and see for yourself. I wonder if any vintage ham rcvrs have a phono input?

    1. Forgot this is the literal internet. Just kidding about the 60 Hz.

    2. I have a early 50's Hallicrafters S-53A that has a phono input jack in the back. It is switched in by turning the RF Gain control all the way CCW.
      Doug - W8NFT

  2. Thanks Doug. I see the Hallicrafters SX-100 does as well. Google shows circuits to convert Raspberry Pi audio to phono input.

  3. I wonder if this circuit would adapt to using a 12AF6 tube. It is the same pin-out as the 12AU6 (pentode) but uses just 12 volts on the plate. A bit lower transconductance, but using headphones it should prove to be doable. This would make an interesting hack. Bruce - KK0S


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