ARP 4014 Balanced (RING) Modulator

[Mike Granger]

Hey folks...

I finished a project recently that would not have been possible without
this list. I found Joachim Verghese's ARP TECH website because I saw a
message on the list refering to it awhile back. He recently made
available the schematic of an ARP module (4012 Ring Modulator) I have
wanted to add to my home grown modular that was built in 1973. I had
worked with an early ARP 2600 synth at Cal State Long Beach in the early
70's, and always loved the ring mod in that synth.

I finished building one for myself last night, and it worked when I
first turned it on! Out of all the projects I've built over the years,
this is unusual....I almost always miswire at least one thing.  I was
ecstatic when I looked at the output waveforms on my scope. The
modulation was beautiful! And the sound of the module brought back
memories of when I programmed the 2600 at Long Beach State when I was
there in the music lab all those long nights.

I built the whole module out of identically matched transistors,
(matched on my curve tracer ) 2n4401's and 2n4403's.  I even gain
matched the pnp's to the npn's and
matched the Vbe's. Probably overkill, but I was doing it for fun.

Anyway, thanks to Joachim and this list for helping me make this 25 year
old dream a reality.

Now for the Mic Preamp, Sample and Hold, etc., etc................

Mike Granger