Thursday, 5 March 2020

Synthesizer Build part-22: RING MODULATOR (Yusynth design).

An excellent ring-modulator to serve as an extra source of weird sounds. This one is simple to build and works very well.

The ring-modulator was something I always wanted to include in my DIY synthesizer and I was thinking of doing it the old fashioned way with audio transformers but they are very expensive. So I went looking for designs that used semiconductors and came across the Yusynth design. I ordered some MC1496N IC's from a shop near where I live because I didn't want to wait for components from China, what with the Corona virus going on etc.
I got the chips the next day and I set out to make a stripboard layout.

Click here to go to the schematic.  Here is the (verified) stripboard layout I made from it. The schematic is for a double ring modulator but I only built one. But it's just the same circuit repeated. I used this layout for my build so it is tried and tested. Note that the electrolytic capacitor on the AC Output has it's polarity reversed from those on the AC Inputs.


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Bill of Materials:



The circuit has two trimmer potmeters and the way I tuned it was to create a sinewave with the LFO of about 400 Hz and feed that into input B and a triangle wave coming from VCO-1 fed into input A and I had the little oscilloscope connected to the output. I turned the trimmers in such a way that I got the following picture on the oscilloscope:



The triangle wave appears inside the sinewave so to speak and you trim it until the low amplitude sides are flat and so you get a whole row of these modulated sinewaves. If you turn the trimmers you can see the symmetry changing and it becomes flatter at the top or bottom. So I tuned it until it was a nice symmetrical waveform. There apparently is also a DC-Offset that needs to be trimmed away (according to the text with the schematic) but I haven't tried that yet. For now I just use the AC inputs anyway. This ring-modulator can handle 10Vpp signals like all the builds on this website. I use the Moog 10 V peak to peak as a standard for my DIY synthesizer.

Ring modulation is a very interesting way of combining two frequencies and can get very complex very quickly if you use waves that have a lot of harmonic content like squarewaves. More on the theory involved is here on this Wikipedia page about ring modulation.

And that's it. I didn't think I could fit any more modules in, but this one was just small enough to go into the wood panel above the modules. Here's a look at the finished panel and how I fit the stripboard behind it with a little copper L-Bracket I made myself and soldered onto the stripboard.




Ignore the sawdust specks in the bottom picture, LOL. I took it just after putting the module in and the synth was covered in fine dust.
Okay that's another one done. This is getting to be quite a big and powerful "sound design machine." It's about time I made a new case that I can put on top of this synthesizer so I can keep building ^___^

If you have any questions please leave them in the comments below!



3 comments:

  1. hi eddy, do you have a video or sound demo of this? also (again), does it work on 12v? cheers

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    Replies
    1. No I'm sorry I have no demo of this. I actually used it just a moment ago. You can get weird sound combinations with is and if you feed it 2 sinewaves, one lower than the other, it produces sort of bell like sounds. It's really cool. Should work fine on dual 12V. I might make a demo of it later.

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    2. sounds good. what do you feed into which input on this module?
      do you reckon there is a difference between 1496N and 1496P?

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