Doepfer A-136 Distortion/Waveshaper Tutorial Videos by Raul Pena

Raul Pena published new videos demonstrating the A-136 Distortion/Waveshaper Module

Module A-136 is a distortion and waveshaping module with extensive control possibilities. The incoming audio or cv signal is internally divided into 3 sections:
- positive component of the signal with adjustable clipping level (even externally via jack socket) and positive or negative amplification (+/-) of this component
- negative component of the signal with adjustable clipping level (even externally via jack socket) and positive or negative amplification (+/-) of this component
- original signal with positive or negative amplification (+/-)

Different settings of 5 distortion/waveshaping parameters enable a lot of very complex and extreme waveform modifications. The range of modifications reaches from simple soft or hard clipping to completely altered waveforms where the original signal is no longer recognizable.
The sketch below shows only a few examples when using a triangle as input signal.

Applications: audio distortion (especially in combination with filters very interesting), waveform modification for audio signals as well as for control voltages (LFO, ADSR, random etc.).

Video: Doepfer A136 Distortion/Waveshaper Basics and Demos (Full Playlist)

Modular Wild Presents Profile - Malekko Heavy Industry Richter Megawave

Malekko Heavy Industry Richter Megawave

Another new video series by Raul Pena starts this week!

" The Malekko/Richter Megawave is a selectable wavetable device featuring many of the available preset Wiard Miniwave ROM waveforms.

Each of the ten ROM selections contains 256 waveforms.
It's not an oscillator, the Megawave can be used as an audio wave shaper, complex LFO function generator, stage quantizer, random function generator, non-linear waveform distortion unit, etc.

WAVE, BANK, and ROM selection are all voltage controllable and each CV input has fine control.

The Megawave wavetable device is 16HP wide, 35mm deep, and consumes around 90mA power."

Find more info via http://malekkoheavyindustry.com/
Malekko on Twitter: https://twitter.com/malekkoheavy

Video 1: Modular Wild - Profile-Malekko Heavy Industry Richter Megawave

" A short overview of the basic features of the Malekko Heavy Industry Richter Megawave.
Sound and Video by Raul Pena."

Video Playlist: Modular Wild - Malekko Heavy Industry - Richter Megawave- Banks 0-10

More videos will be added to this playlist automagically...

Check out Raul's latest survey athttp://www.surveymonkey.com/s/K3Z9PVF

Other places to find Raul's World of Synths on the Web:

raulsworldofsynths on YouTube

raulsworldofsynths on Vimeo

raulsworldofsynths on SoundCloud

raulsworldofsynths at iTunes

raulsworldofsynths at CDBABY

A-136 Pre-amp Modification

I discovered another nice light-weight DIY-project on the Doepfer DIY-page.

Locating the R2 resistor

It seems that the A-136 Distortion/Waveshaper module contains an internal pre-amplifier that is used to amplify the input signal by about 3.5 before it is processed by the A-136.
Especially for low level audio signals (e.g. output from a VCF) this is useful.

But for all signals with a level beyond ~ 7V this causes clipping before the internal processing takes place. 

Especially for the processing of LFOs or unfiltered VCOs this may cause a problem.

The wiring, additional pictures
on the PatchPierre Facebook page

To totally bypass the internal pre-amplifier, resistor R2 can be removed (e.g. by pinching off).

R2 is the resistor in the upper third of the pcb which is very close to the rear edge.
When R2 is removed the amplification of the internal pre-amplifier becomes "1" (which means that it does no longer amplify).

Finished modified A-136 

Because i love to keep myself busy (I'm slightly ADD-ish), i decided to add a switch to the module, so i can switch between pre-amplifier on and off modes.
It looked like an easy project, so... what could go wrong? ;-)

Besides the front-panel it was a pretty easy job;
I desoldered one side of the R2 resistor, bent it over towards the switch, and wired it with black wire.
After that i soldered another wire (red) from the switch to the hole where R2 used to be. Easy as that.

Now i can manually switch the internal amplifier on and off when required.
The clipping did annoy me at times and now i prevent that and try the un-amplified signal with alternate settings*.
it's not a groundbreaking project, but a nice extra.

* In addition one has to pay attention that the knob positions may vary a bit from the front panel printing because of mechanical tolerances of the potentiometers and knobs (i.e. "0" is not always exactly the neutral position for "A", "+A" or "-A")

The modifications described on this site will most likely void any warranty and, if not done carefully, can damage the circuit board, IC chips, and faceplates.
PatchPierre can not be held responsible for any damage.

A-136 Distortion / Waveshaper

The A-136 Distortion/Waveshaper module is a nice distortion/wave-shaping module with external CV control possibilities. It can be used for audio-distortion, but also to modify control voltages ( create new control waveforms made from LFO, ADSR, or Random voltages ) with it.

The module divides the incoming signal into 3 different components; the positive, the negative and the original signal. The 5 knobs and the 2 CV inputs let you adjust the positive and negative amplification and the clipping levels.

With all the different different settings you can create complex wave-shapes and impressive sounds, but to be fair, i have heard better (extended?) distortions. This might perhaps be the reason why Doepfer advices you to use it in combination with filters... not sure though...

For mild and subtle distortions this module sounds alright, but the wilder, clipping distortions are a bit too extreme for me.
Personally i prefer the A-137 Wave Multiplier or the A-116 WP Waveform Processor controlled by random voltages, for the more interesting ( subtle and extremer ) wave-shaping.

Distortion I ( Picture )