Showing posts with label VCF. Show all posts
Showing posts with label VCF. Show all posts

Wednesday, January 24, 2018

Doepfer NAMM 2018 A-100 Standard Module Announcements

A-123-2
My third and last post about the New Doepfer announcements for NAMM 2018... (January 25/28 2018, Anaheim, Hall A, booth 10706)
The other 2 blogposts are about the  Dark Energy III and their new Polyphonic Modules...
Among the newly announced "Standard Modules" there are these little gems

The A-123-2 6/12/18/24dB Highpass Filter is an interesting voltage controlled highpass filter with four filter outputs (6, 12, 18 and 24dB slope). It also features voltage control of the resonance. These controls and in/outputs are available:
• Audio In with attenuator (Lev)
• Manual Frequency control (Frq)
• FCV1: Frequency control input (~ 1V/oct)
• FCV2: Frequency control input with polarizer
• QCV: Resonance control input with attenuator
• Manual Resonance control (Q)
• 6dB Output
• 12dB Output
• 18dB Output
• 24dB Output

A-140-2
The new A-140-2 Dual Micro ADSR
contains double ADSR type envelope generators behind a front panel with 8 HP only. Each ADSR provides these controls and in/outputs:
• Attack (A), manual control
• Decay (D), manual control
• Sustain (S), manual control
• Release (R), manual control
• Gate Input
• Retrigger Input
• CVT Input with attenuator (CVT = CV Time)
• Envelope Output 1
• Envelope Output 2
• LED control

By means of internal jumpers one can select which parameters are controlled by the CVT input (e.g. D only or D+R or A+D+R) and in which direction (i.e. if an increasing CVT shortens or stretches the time parameter in question). By means of another jumpers output 2 can be set to normal or inverted envelope).
Two more jumpers are used for the optional bus
access to the gate signal of the bus for each ADSR.

A-142-3
A-142-3 Envelope Controlled VCA Module A-142-3 is the combination of a simple AD/AR envelope generator and a VCA behind a front panel with 4HP only.
The type of envelope can be selected by means of a toggle switch between A/D (Attack-Decay) and A/R (Attack/Release). Another toggle switch is used to choose envelope or (free running) LFO mode.
The envelope output controls a linear VCA.
These controls and in/outputs are available:
• Attack control
• Decay/Release control
• AD/off/AR switch
• Envelope/LFO switch
• LED (envelope display)
• Gate Input
• Manual gate (momentary switch)
• Envelope Output
• VCA CV Input (normalled to Envelope Output)
• Audio Input with Level control
• Audio Output (the outputs of several A-142-3 can
be internally mixed together)


Furthermore, the modules that were already announced at Superbooth 2017 like the A-138s Mini Stereo Mixer and A-150-8 Octal Voltage Controlled Switch will be available pretty soon now...  and the A-180-9 got a final facelift and got upgraded from 12 to 14 channels through standard network cables.


Read more about those modules at
http://patchpierre.blogspot.nl/2017/04/superbooth-2017-new-doepfer-module.html



Monday, March 10, 2014

Doepfer A-101-6 Six Stage VC Opto FET Filter/Phaser Announced

Another new module announcement from Doepfer.

" A-101-6 is a new filter module that uses so-called opto FETs to control the filter frequency.
A-101-6 Six Stage Opto FET VCF
Opto FETs are very similar to Vactrols but use light depending field effect transistors (FETs) instead of light depending resistors (LDRs).
A Opto FET is a combination of a light depending FET and a LED (light emitting diode) both put into a small light-proof case.

The advantage compared to vactrols is the much faster response of opto FETs compared to LDRs. 
This allows much faster attack/decay times and even FM effects. 
The disadvantage compared to vactrols is that the FET behaves as a normal Ohm resistor only for small levels. With higher levels the FET begins to distort.
Apart from this the notes mentioned on the Doepfer Vactrol Basics page are valid.

Module A-101-6 is made of six serial 6dB filter stages. The stages can be switched simultaneously to lowpass, highpass or one of two allpass types.
The following schematics show one of the six serial stages in the four possible modes:

A-101-6 Principle Schematics
The variable resistor shown in the schematics corresponds to the opto FET.
The type of filter is selected by two toggle switches or 2 control inputs.
The upper switch selects between lowpass and highpass provided that the lower switch is in the LP/HP position.
When the lower switch in the AP (allpass) position the upper switch is used to select between the two allpass types. Instead of the switches even external control voltages can be used (CV LP/HP, CV Allpass sockets).
For this the toggle switch in question has to be in the left position.

The brightness of the Opto FET LEDs and consequently the filter frequency can be adjusted manually (Frequ. control) and controlled by means of an external control voltage (CV) with attenuator.
The LED at the front panel reflects the LED brightness inside the opto FETs.

The resonance is controlled by the Feedback control up to self oscillation. By means of two trimming potentiometers the maximal feedback can be adjusted separately for LP/HP and allpass mode.
High feedback values can be used mainly in the allpass mode to obtain very extreme self oscillation sounds. Even an external feedback signal can be used instead of the internal feedback connection (FB In socket).

The Mix control is used to pan between the original signal (CCW position) and the effect signal (CW position).
In filter mode (LP/HP) this control is usually set fully CW.
In the allpass modes one obtains phasing sounds at center position or "pure" allpass sound in fully CW position."

Update May 6th 2014:
" thank you for your interest in the planned module.
Because of several suggestions by customers there will be probably some additions (like voltage
controlled dry/wet mix and maybe voltage controlled resonance/feedback).
So it will still take some time until the module is available.
An experienced A-100 user is currently about to try out the prototype (still without the additional voltage controlled features) and we wait for his assessment about the features of the module before we continue.
If the module is back I can do some demos." *source Dieter Doepfer

Release date and price for this module are not yet available.
Source: http://www.doepfer.de/a1016.htm
Read more about Opto-Isolators at http://en.wikipedia.org/wiki/Opto-isolator
and more about Vactrols at http://patchpierre.blogspot.nl/2011/02/vactrol-basics.html

The new Doepfer modules will be shown at #MusikMesse in the booth of their distributor Alex4 in hall 5.1, booth nr. C54