Vacuum Tube Ring Modulator

This is, of course, based on Eric Barbour’s designs, with a few twists.

I built a separate sine/square wave oscillator and have put an input jack on the front of the ring mod for input of any carrier signal.

Basically, the first jack is the straight signal input.  It feeds a 6ej7 pentode, then the volume pot below the jack, then pin 6 of the sheet beam tube.

The second jack is the carrier input, which feeds 1/2 of a 12ax7, a volume pot, the second 1/2 12ax7, then the beam deflection pins.

The top switch takes the straight input and switches it to the carrier circuit, cutting off the carrier input.  This creates some weird and useful sounds, especially in conjunction with the bottom switch, toggles the value of the 12ax7’s first cathode resistor bypass cap between 10 uf and .01uf.

The third pot is screen voltage control for the sheet beam tube and the last jack and pot are output.

The Parker Steam Synthesizer is finished (and works!)

Lorin Parker’s steam synthesizer was posted earlier, but the information linked was at least 2 years old…

Steam synth in operation

The steam synthesizer has been fully operational for more than a year!!

It generates electronic sound through a modified dynamo, and, well, hisses and clacks like a steam engine.. . No electricity is used to generate an electronic signal. Only fire, heat, steam and metal!

New video, audio and info about the Parker Steam Synthesizer can be found here:

Furthermore, Lorin Parker has recently started Electric Western, a DIY oriented site for the dissemination of deviant and expressive electronic instruments. Many other instruments are showing up there as the site grows, and Electric Western will be providing unique kits and instruments in the near future.

If you build your own synth modules, you MUST join this Yahoo group.

Modular Synth Panels

Members include just about all the well-known DIYers. They post FPD files for their custom modules. FPD is Front Panel Designer, the software used by Schaeffer USA to allow hobbyists to design and order their own machine-engraved aluminum panels. All you do is load the proper FPD file in the program, and then you can order finished panels directly via internet connection. Or, use the panel layouts as masters to design your own custom panels. It’s a very easy-to-use, basic CAD program.

I’ve used Front Panel Designer for prototypes and custom jobs, and the resulting panels are beautiful. They are anodized, and various anodizing colors (and colors of engraved text and graphics) are available.

Some of the panels that group members have made:
Bob K Modular

Plague Bearer v1.1*

Plague Bearer v1.0

Plague Bearer v1.1 is now available for order!

*picture is of v1.0

Yup, been busy. Here’s more/other info from our July newsletter:

Now that the madness of developing the Parasite is over, we can tell you about some new developments and upcoming offerings.

  • Some of our behind-the-scenes business deals were finalized yesterday, enabling us to receive much better volume pricing on many components and services. Now we get to pass the savings on to you as well! For starters, the price of the Parasite is now just $185.00.
  • A stash of the enclosures used to build both the Parasite and the Plague Bearer has been discovered! We are happy to announce a run of twenty v1.1 Plague Bearers, at $240 each. Version 1.1 has a few changes, mostly internal – PCB layout tweaks and Power Supply changes. The patch panel will be all 3.5mm jacks as well. The Parasite v1.0 run has been extended to 50.


  • Modular versions of the Plague Bearer, Parasite, and the Infernal Noise Machine are in development.
  • The standalone version of the I.N.M and the Imp should be available soon, with custom wood enclosures, which leads us to:
  • We have expanded our crony resource list to include a custom cabinetry manufacturer, and will be offering custom wood enclosures soon.
  • And a few more things to be revealed in the future…

don’t call it steampunk…

Heres a shot of my modular as of about 12/07. I’ve been working on it off and on for about a year now.

The panels are brass and were etched at home using an electrolytic process.
I just moved, so progress has slowed down, but once this cabinet is stuffed I’m going to start a second ‘controller’ cabinet.
I chose brass because I can cheaply etch it at home. Panels run me about $2 ea. on average.
More pics HERE

crappy youtube vid HERE

sweet petey garbage synth

here’s pretty petey – i made it in 3 days – took another day to get on the panel. panel was a used

panel i had drilled holes into in 2000 (got the panel from weird stuff/nasa) – all pots were pulled

from a dead mixer – all chips and capacitors were pulled from dead electronics pcbs laying around.

the 3372 was pulled from my chroma polaris that went bad years ago (you do the membrane upgrade,

not me). – so vco / noise/vc mixer/vcf/vca with the asm-1 lfo and ian fritz’ ad/ar circuit. the vco is rene’s 4069 VCO – the noise is gravenhorst’s PIC based digital noise – which i had in another unit that i took apart. noise enters the synth through the VCO’s pulse width input via a pushpull pot/switch (pot is pitch) – – crap beats from mpc1k – midi from it to paia midi2cv8 to petey — sorry its not more deviant -b ut it is garbage. sorry the resistors and diodes were new….