Doepfer MMR4/4 MIDI Merger/Router

In September 1996 Doepfer released the MMR4/4, a dedicated MIDI Merger/ Router module.

This versatile module, available in 2 sizes (standard case 200 x 100 x 42 mm or the 19" version with 1 HU), was equipped with 4 MIDI inputs and 4 MIDI outputs on the backside.
It did not have an on/off switch, and had to be powered by an external power supply.

Inputs and outputs could be easily assigned in any combination. 

If you'd assign multiple inputs to a single output, the signals got merged.

The routing was set with 8 buttons and 8 LEDs at the front panel that were assigned to the 4 MIDI inputs and outputs.

The MMR4/4 had 4 non volatile memories (Presets) to store 4 different matrix configurations.
The LEDs displayed the input/output configuration and could be changed very easy with the corresponding buttons.
During normal operation (monitor mode) the LEDs displayed the MIDI activities on the inputs and outputs.
A panic button was available transmitting "all notes off" on all channels and outputs if activated.

Around 600 of these units were made until they stopped selling the last ones in March 2001
There are no plans of a re-release of this module.

Find out more in the online manual HERE

Doepfer A-172 Max/Min patches by Pete Shambler

Pete Shambler has made a nice video demonstrating the Doepfer A-172 Minimum/Maximum Selector module.
In the video he shows some of the ways he tends to use it... pretty interesting...


" Five quick patches with the Doepfer A-172 Max/Min utility module. The first three are in stereo, so headphones are recommended!"

More info at http://www.theshamblers.blogspot.nl/
,and find more about the A-172 HERE

New Doepfer Re-Designs Due to CA3080 Shortage

After the unplanned re-design of the Dark Energy (due to the unavailability of the CEM3394 chip ) there now seem to be more re-designs of Doepfer Modules coming up.

This time the problem is the availability of CA3080 (and 3080E) chips.
The CA3080 (datasheet PDF) is a 2MHz Operational Trans-conductance Amplifier (OTA), which is used in quite a few Doepfer (and other brands) modules and there seems to be no direct replacement equivalent.
The original chip itself hasn't been produced since 1975 and the wafers have all been used up a couple of years ago, according to some sources.

No-one seems to have decent stock anymore, and there was a buying craze when it went out of production.

That does mean that some Doepfer modules have to be re-designed in the near future because of this obsolete integrated circuit ( like the A-107, A-116, A-127, A-130, A-131, A-132-1, A-141, A-142-1, A-147, A-171). 

This will take a lot of precious time for Doepfer that would otherwise be spent on manufacturing new modules.

Sadly these re-designs will not have any obvious benefit for the customers.

A-127 Triple VC Resonance Filter Videos by Raul Pena

Raul Pena (from http://raulsworldofsynths.com/ ) has published the four A-127 Triple Voltage Controlled Resonant Filter tutorial demo's.
As most of you already know, this is one of my most favorite Doepfer filters, see more of my posts about this module HERE, so i was kinda looking forward to these video's.

Video 1: Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter Part One-Introduction

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter.Focus on Basic Features. One of four videos. Next in series Modulation.
Audio Loops by Raul Pena.Sound and Video by Raul Pena."

Video 2: Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter Part Two-Modulation

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter. Focus on Modulation of Resonant Filters. Number Two of four videos. Next in series More Modulation.
Audio Loops by Raul Pena. Sound and Video by Raul Pena."

Video 3: Doepfer A127 Triple Voltage Controlled Resonant Filter Part Three-More Modulation

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter.Focus on Modulation of Resonant Filters by Sample and Hold.

Number Three of four videos. Next in series Audio Rate Modulation.
Audio Loops by Raul Pena. Sound and Video by Raul Pena."

Video 4: Doepfer A127 Triple Voltage Controlled Resonant Filter Part Four-Audio Rate Modulation

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter.Focus on Audio Rate Modulation of Resonant Filters.Demonstration of audio distortion with the A127.Number four of four videos.Audio Loops by Raul Pena.Sound and Video by Raul Pena. "

A-116 Voltage Controlled Waveform Processor

Another good way to mess up your audio (and CV signals) is with the A-116 VC Waveform Processor module.

After the input amplifier, the signal goes through two parallel processors: a clipping circuit, and an asymmetrical amplifier.
In a way you could see this module as a cut-down version of the A-137-1 that i reviewed in an earlier post.
Cut-down, but still very effective...

The processed signals are added together and sent to the output.
Clipping-Level and Symmetry amounts are manually controllable, but can also be modulated by control voltages like ADSR's, LFO's, Noise, etcetera.

It is a fun module to experiment with, although i haven't used it in a while.
Take a look at the video by Hawklord2112 that gives a nice impression of what this module can do.

Video: A-116 Demo

" basic functions of the A116 VC Waveform Processor from Doepfer. "

Find more of his videos at http://www.youtube.com/hawklord2112

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.

Future Modules Update

Last week, Dieter Doepfer took the time to answer some questions in the Yahoo Doepfer A-100 Usergroup on the state of the new modules that will be released this year. I did mention most of them earlier, so no big news this time, but some really informative background info.

About the A-190-5 (four voice polyphonic Midi to CV/Gate interface):
" The new A-190-5 prototype (version with LC display) is on my table since a couple of months. But we did not continue because of some more important projects (e.g. Dark Time, Dark Energy II). I think we will be able to finish the hardware until summer (end of summer is in September :-) but I don't think that the final firmware with all planned modes will ready at that time. But we plan to add the firmware update feature via the USB interface."

Doepfer A-157 Trigger Sequencer, as shown at
MusikMesse 2012. Picture by @Cymatics

A-157 Trigger Sequencer -update:
" We are working on the A-157 right now. The new button/LED board with 16x8 is already made and tested. But we are about to redesign the control board as we determined that the microcontroller used in the first prototype (the pictures with the 8x8 board) is not powerful enough for all planned features. In addition the manufacturer announced the discontinuation of the chip. So it will still take some time until the module is ready."

He continued:
" I hope that these 3 new modules will available during this year: A-192-2 /CV/Gate-to-Midi/USB converter), A-190-5 (polyphonic USB/Midi-to-CV/Gate interface), A-157-1 (16x8 LED/button board with 8 trigger outputs), A-157-2 (control board #1 for A-157-1).
But I'm not sure about the order of the release dates.
Probably the A-192-2 will be the first one as the development is nearly finished (we have to built one more prototype and hope it will be the last one).

We (also) think about a "real" ASR (analog shift register) module because the A-152 cannot be used as ASR in all applications.
But this has no priority at the moment and is not yet mentioned in our list of planned modules."

Note: Please don't call or mail them too often at Doepfer about release-dates or updates of future modules. The Doepfer website is updated very regularly, so you will find all the latest info THERE...