Showing posts from October, 2018

Zener Synth Distortion: alive and kicking (with sound file and scope photos)

Hello Again.  This time closing out the "Zener Synth Distortion" Project.

You can read Part I, how I stumbled upon this circuit, here.

They are up and running,  panels Lazertran'd, ready to go.

Here are the two zener distortion units in my rack:

This is a super simple build, almost no parts!

How does it sound?  you be the judge! I have uploaded a demo sound file on Soundcloud.

I tried to give the most objective before/after demo of the 2 modules as I could. No reverb, no filters, no echo etc.  How boring right?

 Here is how I patched my fully DIY home grown works most of the time modular synthesizer to get the demo sound going:

On the demo the first few sounds are from the "Zener" design:

"Zener" provides in your face, loud, crunchy distortion and greatly emphasizes beat frequencies.  maybe a bit much?

The rest of the demo (the last 3:30 or so worth) is "Son of Zener", a lot more subtle.

Shorts anyone? On "ElectroMusic" forum there …

Thomas Henry 13700 based VCO: All hail the mighty Henry!

How much have I learned from Thomas Henry's books?  Well it's all relative I guess but for me,  a lot!  I went from zero knowledge about OTA's to well, some knowledge? Two of his books are both recommended if you want to learn how older OTA synth designs work: "Making music with the 3080" and "An Analog Synthesizer for the 21st century".

Each book features schematics for different VCO's.  The former, 3080 based; the latter 13700 based.

If you've studied audioDIY for synths you've probably run into these IC's before; in goes (low) voltage; out comes current, and best of all, you can control the output current in a fairly linear fashion with an independent "gain" current.  But it's not quite that easy:
The gain input lives a diode drop above V--.  So to make this go, you often have to suck current OUT of the chip which seems to me oddly counterintuitive. Hello?.....OK....If you put too much current into the gain pin (2mA I th…

Discovered by accident: Low parts count waveshaper/modulator/distortion circuits!

At the bench trying to learn more about inductors--something I've not worked with a lot with before--so bought a few Neutrik NTE1s from Amazon.

It's a 1:1 transformer (making the math easier I figure) and has decent audio specs.  And it's cheap--about $14USD each, for decent audio performance; good for experimenting.

What can we do with this little gadget?

Benchtime! my goal one day is to come up with something cool like the Moog 914 (yeh right, I have a long way to go).  breadboarding up some transfomer/cap widgets, got bored, some inductor/transformer/RC/op amp widgets, got bored again, so breadboarded some transfomer/zener widgets,  when all of a sudden I heard what sounded like a balanced modulator output coming from the my bench's audio monitor.


I looked over my work and realized (after a bit) an op amp I was using as an output buffer was oscillating (unintentionally) and I wired things backwards, confusing the breadboard inputs with its outputs!!

So instead…