Doepfer A-135-4A/B/C Voltage Controlled Performance Mixer Modules Announced

The A-135-4A and B prototypes on display
at the Amsterdam Dance Event in
October 2016

In a previous blogpost I was rather excited about my own new A-138p/o Performance mixer combo.
I bought i just right before I knew that Doepfer was working on a voltage controlled version of this module...

On first impression, the new A-135-4A Voltage Controlled Performance Mixer looks quite the same as the non-cv-controllable A-138p Performance Mixer, only with extra LEDs for displaying the incoming CV voltages for all parameters (except Gain).

Module A-135-4B is the CV-input module, where 16 different control voltages can alter 16 parameters on the A-135-4A Mixer... The modules must be connected via an int 20pin ribbon-cable.

Module A-135-4C is a four-fold envelope follower with adjustable attack and release time for each channel.
The main function of the module is to derive four envelopes from the A-135-4A audio input signals. These voltages can be used to control parameters of the main module A-135-4A via the CV input module A-135-4B2. Typical applications are ducking (e.i. the signal of one channel is used to mute another channel more or less), as well as compressor and expander functions.

A-135-4A/B/C VC Performance mixer prototype
with the A-138o Output module

A-135-4B CV Inputs Module close-up

The modules of the A-135-4 series can be combined with the (non voltage controlled) mixer modules A-138o/p so that these can be used as output module for the A-135-4A. A-135-4A and A-138p can be connected together to the same A-138o to obtain e.g. four fully voltage controlled channels (A-135-4A) and four manually controlled channels (A-138p).

This combo will probably available before spring of this year.

Source:
Preliminary info via http://www.doepfer.de/A1354.htm

Doepfer A-110-4 Thru Zero Quadrature VCO Announced

Doepfer's latest module-announcement is the A-110-4 Thru Zero Quadrature VCO.

I do have to dig a bit deeper into this module before i completely understand it, but here is the text from the Doepfer website, where they will soon have audio examples and oscilloscope views available...

Doepfer A-110-4
Thru Zero Quadrature VCO

" The term "quadrature" means in this connection that the oscillator outputs sine and cosine waveforms simultaneously. 

The term "Thru-Zero" means that even "negative" frequencies are generated. 

This can be a bit of a misleading term as negative frequencies do not really exist. 

"Negative" means in this connection simply that the sine/cosine waves will stop when the linear control voltage reaches 0V and continue with the opposite direction as the linear control voltage becomes negative and vice versa.

The module has two control sections: linear and a exponential. 

The exponential section consists of the XTune control, the 1V/Oct input and the XFM input with the corresponding attenuator XFM. 

The exponential control voltage is the sum of these three voltages. 

The linear section consists of the LTune control and the LFM input with the corresponding attenuator LFM. 

The linear control voltage is the sum of these two voltages. 

A dual color LED is used to display the polarity of the linear control voltage (green = positive, red = negative). 

The resultion pitch of the sine/cosine outputs is determined by the resulting control voltages of both sections. The linear section is used to control the pitch in a linear manner. 

When the LTune control (LTune means Linear Tune) is fully CW the module works like a normal Quadrature VCO (e.g. like the A-143-9) and the LED lights green. 

The pitch is then controlled by the exponential section with the manual Tune control and the exponential frequency control inputs 1V/Oct and XFM. 1V/Oct is used to control the pitch by a 1V/Oct CV source (e.g. sequencer or Midi/USB-to-CV interface). 

XFM is used to apply an exponential frequency modulation with adjustable depth (e.g. from an LFO or another VCO). 

As the LTune control is turned counterclockwise starting from the fully CW position the frequency is lowered in a linear manner until the sine/cosine waves stop near the center position of LTune (provided that no LFM signal is present). 

As the LTune control is moved from the center towards the CCW position the waves start again but into reverse direction and the LED turns red. 

When the fully CCW position of LTune is reached the module works again like a normal Quadrature VCO. 

But much more exciting is the usage of the LFM input to modify the linear control voltage by an external control voltage (typically another VCO). 

Linear modulation by another oscillator using the thru zero feature generates audio spectra than cannot be obtained from an oscillator without the thru zero function. 

The reason is that a "normal" VCO will simply stop as the linear control voltage becomes zero or negative. 

But a thru zero VCO will start again with "negative" frequencies as the the linear control voltage becomes negative.

The main advantage of the A-110-4 compared to other Thru Zero VCOs is that the design used a sine/cosine core. The sine/cosine waves are not derived from other waveforms (e.g. sawtooth or triangle) by means of waveshaping. 

Rather the sine and cosine waves are the core of the VCO which results in very pure waves with a minimum of distortion and overtones." 

The A-110-4 is planned for early 2015, price ~ Euro 120.00

Source: Doepfer website

Doepfer A-135-1 Quad VCA/ VC Mixer Tutorial Videos by Raul Pena

Time for another new tutorial series by Raul Pena.
The subject this time is the Doepfer A-135-1 Quad VCA /Voltage Controlled Mixer (version 2)

Video 1: Doepfer A135-1 QVCA/VCMIX basics

" A short description of the beasic features and functions of the Doepfer A135-1 Quad Linear VCA, Voltage Controlled Mixer. Sound and Video by Raul Pena."

Video 2: Doepfer A135 Quad Linear VCA/ Voltage Controlled Mixer Audio Demonstration One
" A short demonstration of A135 Quad Linear VCA with oscilloscope views to show how external cv effects amplitude of an audio signal. Sound and Video by Raul Pena."

Video 3: Doepfer A135 Quad Linear VCA/ Voltage Controlled Mixer Audio Demonstration Two

The second of two Audio Demonstrations of A135 Quad Linear VCA with oscilloscope views to show how external cv effects amplitude of an audio signal. Sound and Video by Raul Pena.

New videos in this series will be added to this post weekly on Thursdays.

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

Doepfer A-135-1 Voltage Controlled Mixer Re-Design

Old version of the A-135

The original A-135 module was a simple quad voltage controlled mixer.
It was made of 4 independent linear VCA's, mixed to one common output.
For each VCA the following inputs and controls were available: audio input with attenuator, control voltage input with attenuator, gain (pre-amplification).
The VCA's were realized with high-quality CEM VCA's (CEM3381).

The module could be used for voltage controlled mixing of up to 4 audio signals with separate control voltages (e.g. by LFO's, ADSR's, Random, Shepard generator, MIDI-to-CV interface or other control voltage sources).

In June last year, Doepfer announced the re-design of several modules because of shortage of CEM3080 Chips that were used in this A-135 and other modules.
This year a few of these re-designed modules were released, each in a slightly extended/ improved version (like the A-130/131 that are now also DC-coupled, and the recently announced A-141-2).*

A-135-1 Redesign of the A-135

This new version of the A-135 also has some nice extras in the form of a Sum Out and 4 single outputs for each channel instead of only one (Mixed) Audio output on the original A-135.
They've also managed to make it only 18 HP instead of  22 HP wide.

The new version of the A-135-1 is also able to process slowly varying control voltages because the signal in/outputs are DC coupled.

The new version is manufactured from May 2013 and is available now.

* More re-designs were also promised to us last year, like the A-107, A-116, A-127, A-132-1, A-147, A-171), so that promises a lot for the future...

Find more about various Doepfer re-designs via http://patchpierre.blogspot.nl/search/label/Re-design

A-142-4 plus Expander Demo by Hawklord2112

Regular video-uploader and contributor to the blog Hawklord2112 uploaded another nice new video.

He bought himself a new A-142-4 Quad Decay module and also an extra expander module for it.
Each of the 4 sub-units of the A-142-4 has a pin header with two pins available.

When the two pins are shortened (e.g. by means of a jumper on the PCB board or a toggle switch connected to the two pins) the corresponding sub-unit changes to a loop mode. 

In this mode the unit triggers itself like an LFO..

The expander is made of a pre-manufactured panel, punched for 8 sockets, almost identical to the A-180 front panel but without the printing.
Those panels are very useful for DIY-projects like this.
In his video he explains how it all works.

Video: A-142-4

"Basic demo of the Doepfer A142.4 Quad Decay generator and DIY breakout expander"

Uploaded by hawklord2112

A-143-9 Demo by Hawklord2112

Video: A-143-9 Demo

" Simple runthrough of the Doepfer A143-9 VCQLFO"

Uploaded by hawklord2112
Twitter: https://twitter.com/hawklord2112

A-143-2 Quad ADSR - Power to the Quads!

Good value-for-money and serious rackspace-savers are Doepfer's Quad modules.
These modules offer four (-duh-) identical but individual modulation sources in one module.

My A-143-2 Quad ADSR is at the heart of my A-100 system.
With 4 envelope generators in one this is a very powerful module, and this is where the 3 individual gate outputs from my MAQ 16/3 come together.
Also see THIS post.

The Gate inputs of the units 2, 3 and 4 are normalled to the Gate input of unit 1, so Gate input 1 is connected to the switching contacts of the Gate input sockets fom submodule 2, 3 and 4 if no other input is connected.
With only one Gate signal applied to Gate input 1, it can be used to trigger all four sub-modules simultaneously.
A switch for each individual channel is available for switching between high, low and medium ranges.

All 4 sub-units have additional input sockets for Re-Trigger, but the re-trigger behaviour of the A-143-2 is slightly different compared to other envelope generators;
During the attack phase the envelope cannot be re-triggered or reset. (unlike the A-140 ADSR envelope, that envelope can be re-triggered while the gate is still open).

Each sub-unit also has three digital outputs (high/low) that sends a trigger signal at the End of Attack (EOA), End of Decay (EOD) and End of Release (EOR).

This is very useful if you want to daisy-chain the sub-modules to create more complex envelopes. (or even complete loops)
The envelope outputs are displayed with LEDs and the maximal envelope voltage (Attack/Decay reversal point) is about +8V.

The Quad series consists of the following Multiple modulation sources so far;
A-143-1 Quad AD, A-143-2 Quad ADSR 
A-143-3 Quad LFO, A-143-4
Quad VCLFO/VCO (just released), A-143-9
VC Quadrature LFO and modules A-142-4 Quad Decay, plus Quad Amplifiers A-132-2 Quad VCA I and A-132-4Quad exp. VCA