Doepfer A137-2 VC Wave Multiplier II Tutorials by Raul Pena

A-137-2 Wave Multiplier II

Back in August of this year Raul Pena published his series on the Doepfer A-137-1 Wave Multiplier module (11 parts!)

Now he's back with the first tutorial videos starring the follow-up to this module, the A-137-2.
The A-137-2 is another version of a wave multiplier.
In contrast to the A-137-1 Wavemultiplier I the A-137-2 generates four phase-shifted copies of a VCO signal applied to the audio input. The four shifted signals are added to the original signal to obtain a fat sound similar to five independent VCOs.

Doepfer A137-2 VC Wave Multiplier II (Playlist)

"A short overview of the basic features of the Doepfer A137-2 Voltage Controlled Wave Multiplier II. Includes a short demonstration of a few oscilloscope views. Sound and Video by Raul Pena."

Check out Raul's latest survey at http://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

More A-137-2:

Patch-of-the-day with A-137-2 from Navs: 

http://navsmodularlab.blogspot.com/2012/01/patch-of-day-highly-strung.html

http://navsmodularlab.blogspot.com/2012/01/patch-tips-21-getting-animated.html

http://navsmodularlab.blogspot.com/2008/12/doepfer-137-2-wave-multiplier-ii-demo.html

A-137 Wave Multiplier

I might have underrated the A-137-1 Voltage Controlled Wave Multiplier a bit. Until lately...

The basic idea of a wave multiplier is to multiply the waveform of an incoming signal and add harmonics to a signal that contains none or only a few harmonics (e.g. sine or triangle waveform)
The A-137 can be used with signals rich in harmonics too (e.g. saw) but the effect is not as remarkable as for triangle or sine waves.
For rectangle signals none or only little effects are obtained.

The A-137 is a very interesting module, in a way it is quite similar to the A-136 Distortion/Waveshaper
You can compare it with four simple A136 modules in series. (The A136 is basically like a guitar distortion stompbox with different distortion levels for the positive and the negative parts of the signal.)
Only in this module you do not have separate access to the two half waves and to the parameters of the individual stages.

The parameters of the A-137 are:
- Multiples: defines the number of basic wave multiplications within one period.
- Folding Level and Symmetry: the upper and lower clipping levels of the wave folder units are controlled.
- Harmonics: adds some harmonic content by sharpening the waveform edges and adding overshoot peaks. It works a little bit like the resonance control of a VCF.

All 4 parameters can be manually adjusted and controlled by external voltages.

It is a lot of fun to experiment with this module, with all different parameters controlled by different CV sources like LFO, ADSR's, Ribbon Control pressure and sequenced triggers for example.

The only thing i dislike about this module is the unpredictability factor.
You should be carefull for a 'damping' effect that can occur when different parameters interact with eachother.
But on the other hand; the module is fully DC coupled, so even CV signals can be messed up with this module.

Check out the audio examples on the Doepfer site that explain the function of the module and its parameters.

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.