Ring Modulator PCB Info and Misc Notes

View of the Back Side Where  9mm Alpha POTS Are Mounted


Component Side View


The board layout is tight but very doable. It is designed to fit easily in a 1590BB enclosure and also will fit on the expresspcb’s cheapest  prototype service fixed size 2.5 x 3.8 board  (3 boards for $59.00 delivered ).

Here is the link to the expresspcb layout:  https://www.adrive.com/public/tQPgjW/Ring%20Mod.zip

The Associated Schematic is here:

Couple of notes:  

The Blue LED I use has  a very high turn on voltage of more than 3V. If you use another type,  R13 will definitely need to  be increased perhaps to 2.2k or greater. The part I used is from Digikey and the part number is  OVLLB8C7.

The design uses 9mm alpha pots mounted on the back. Others can be used just connect wires to the pin connection holes on the board.


36 thoughts on “Ring Modulator PCB Info and Misc Notes

  1. I’m very impressed by the range of sound possibilities this circuit offers and would like to try building it. I’ve downloaded the PCB layout, but on checking the costing option in Express PCB, it says that the board does not meet the MiniBoard requirements. Any chance you could check and modify the layout? In fact, any chance that you could sell me a board (even for the MiniBoard deal, Express PCB charge a flat USD59 for postage to the UK)?

  2. Yes I put in a new link which is for the mini-board size -which should work for you. I have one board left which I would give you but I need it so you will have to have some made.

    Remember when you use the mini-board service you have a little excess you must cut off to fit in the 1590 BB. Let me know if you have anymore problems.

  3. Hi Ray,

    First, I want to say “thank you!” for all the great information and explanations you have shared with the community.

    I have a question pertaining to both the Ring Modulator as well as the PWM Compressor. It seems that the TS922 opamp is end of life and very hard to find in a DIP package. I was wondering if you could answer the following:

    1) Is there a suitable substitute which is DIP-8 (through hole) and available? Will the TLC272 work in both the Ring Mod and Compressor? Could you sub in a standard 4558 compatible?

    2) Did you choose the TS922 for these projects because you have a large supply of them, or is it because the rail-to-rail characteristics are truly needed?

    Thank you in advance,


  4. Ray, that is superb! Thank you. I figured that you had a stash of them as they are in many of your builds posted here.

    Also curious if you knew the specs on the TS922 that you use (part suffix would help). It seems there are a few variants with different input offset voltages in 500uV, 900uV, and 3mV…is it imperative that the offset voltage matches the version you have for proper operation?

  5. Ray- in love with this circuit- i would love to get the PCB, but the fileswap link is down now.. any way that i could get that?

  6. New link is up – so go try again. Also look at my PIC DDS. I say this because you could use this circuit for the VLF oscillator and the modulator drive. It would reduce parts count quite a bit! Having said this nothing wrong with the original circuit.

  7. yes I built this modulator for a couple players who really like it. It can generate some really synth like sounds but with the nice dynamics of the guitar. If you build it – let me know if you have any issues.. I built three by my own layout and schematic and all worked well – you don’t have to use the TS922 op amp

    • Yes all the parts are on the schematic- many of them are not critical and I just used what I had …you can use other op amps and whatever type passives(resistors and caps) you want. IC3(the regulator) doesn’t matter – any 5v reg will do. You must use a CD4046 not a 74HC4066. This is because the 74 series device has abrupt VCO behavior at the high end. A TL072 will for example for the op amp. If you have any questions let me know

  8. I have a few more questions:
    would it make sense to try different wave forms for the two oscillators, e.g., square/triangle/sine?
    is it possible to change the filter resonance?
    is it possible to turn the filter on without modulation (0 frequency)?

    Thanks again!

  9. The waveforms don’t make that much difference.I like the triangle wave. I don’t think you can change the resonance.
    yes the depth control makes the modulation depth vary from 0 up to 50%.

  10. This looks nice and I’d like to build one …. however, the link to the pcb is down again….

    thanks, sounds amazing!


  11. Hi Ray!

    Thank you so much for this amazing schematic! I put it down on my breadboard and it works very fine. Just a little noticeable problem, there is a little modulation leakage at the high end, as you mentioned on a previous post. Did you fixed it or is it still on the final version?


  12. I know this is a very old thread, but I was hoping you still check it. This is a great sounding project, and I love me a good ring mod.

    Someone gifted me a completed pcb but I don’t have any of the documentation. I want to make sure that I understand all of the hookups. I believe I can identify the dry and wet signal ins and outs but I’m not 100% on what everything else is.

  13. Hi Ray,
    The link to the pcb file appears to be down again. Can you re-share/upload? I’m excited to try building this!

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