[sdiy] Cool 'ring modulator' schematic

[harrybissell]

Hi Tim...

ok you asked for it.

Its VERY COOL. A must-have imho.

It works well throughout the audio range. And don't believe the
BS about the square wave. Use any waves you like.

The article warns of 'distortion' but you will LOVE the distortion.
I didn't find a setting I did not like ...

I'd set it up with VCAs on the inputs.  Overall sound is dead
quiet.  I used TL072s and 1% resistors.

You can add a cap across the feedback resistor in the output
summer... for HF rolloff. Might be neat to make that switch
selectable.

10K inputs are kind of low, a couple of buffer amps are a nice
add.  Don't forget to put some series resistor in the output or
the TL072 will go nuts !!

BTW... check the schematic carefully. R11 and R4 are in parallel,
so replace them withone 10K instead of two 20Ks

H^) harry

Tim Parkhurst wrote:
> 
> On 2/8/06, harrybissell <harrybissell at prodigy.net> wrote:
> > in the latest issue of Electronic Design (under Design Briefs)
> >
> > This is an opamp based design... it would be above the ARP
> > 'exclusive or' design but below most true four quadrant
> > designs in terms of functionality.
> >
> > READ the last paragraph... note the schematic says "rf"
> > but in reality... 'radio frequency' in this design
> > is probably not more than 10KHz   :^P
> >
> > Still, some may want to play. I might whip one together...
> >
> > H^) harry
> >
> ************************
> Hey Harry,
> 
> Could be interesting. Here's a link
> http://www.elecdesign.com/Articles/ArticleID/11935/11935.html
> 
> The writeup states that the design is 'limited to lower frequencies'
> which sounds like it would work for audio just fine. Also looks like
> it works with a variety of waveforms (unlike the square-only ARP XOR
> design).
> 
> Let us know how it works if you knock one out.
> 
> Pretty please? ;)
> 
> Tim (could be interesting) Servo
> --
> "Imagination is more important than knowledge." - Albert Einstein