Doepfer A-121 Multimode Filter Re-Design

A-121-2 Re-design

We all knew a re-design of the Doepfer A-121 Multimode Filter has been in the pipeline for a while, due to the unavailability of certain chips inside.

Since the beginning this has always been one of my favourite filters, because of it's sophisticated sound and the VC infut for resonance control. Oh, and the multiple simultanuous outputs...

At Namm 2016 Doepfer will present the A-121-2, the successor of the obsolete module A-121.

The circuitry is totally different from the A-121 which used the obsolete CEM3320 filter circuit. 

Module A-121 is a voltage-controlled multi-mode filter with a cut-off slope of -12 dB / octave.

Four simultaneous outputs are available, each with different characteristics: low-pass, band-pass, high-pass and notch (or band reject). 

The cut-off frequency determines the point at which the respective filter effects appear. 

The frequency can be adjusted manually, or by voltage control (Filter modulation, for instance by an LFO or ADSR). 

Two CV inputs are available, whose control voltages are summed. Resonance (Emphasis or Q ) can be adjusted manually, or by voltage control, right up to self-oscillation, in which case it will behave like a sine wave oscillator.

The sound of the new module A-121-2 is identical to filter of the Dark Energy II but has been expanded by the voltage controlled resonance feature (like the original A-121).

Read all about the specs of the original A-121 at http://patchpierre.blogspot.nl/2011/03/filters-ii-121-vcf2-multimode-filter.html

The modules will cost Euro 120.00 and will be available around March 2016

Source: Doepfer.com

Analogue Solutions Telemark Multimode Filter

Analogue Solutions just released their Telemark Multimode Filter module, a eurorack module based on the Telemark multimode filter.

The Telemark multimode filter module is based on the filter of the legendary Telemark semi-modular synthesizer.
It's routes lie in the original 1970s Oberheim SEM, though it has developed a character of its own.
The filter is a 12db/Octave multimode type. Multimode means there are more than one type of filter output.
There are in fact four: low pass, band pass, high pass and notch filter.
Additionally, notch filter can be varied for an even wider range of sounds.
Use of Gain and Q allow for even wider possibilities.
No special knowledge is required to use this filter. Just plug your audio in the left, and your audio out on the right.
Optionally (and recommended!) patch a control voltage in to give the sound movement.

KEY FEATURES OF TMF
- Pure analogue circuitry.
- Telemark filter
- 4 filter types- Low, High, Band, Notch
- Resonance (Q) boost feature
- Slim design
- Spun metal knob caps

More info at http://www.analoguesolutions.org.uk/concussor/tmf.htm

DivKid made another great video demonstrating the module;

Video: Analogue Solutions TMF - Telemark Multimode Filter eurorack module video overview

" New eurorack module - a multimode filter based on the stand alone synth Telemark, from Analogue Solutions.

http://www.analoguesolutions.com

Video by Ben Wilson / DivKid - www.youtube.com/divkidvideo"

Doepfer A101-1 Vactrol Multitype Filter Review by SoloStuff

SoloStuff created a nice review video about the Doepfer A-101-1 Vactrol Multitype Filter and uploaded it to YouTube...

Video: Doepfer A101-1 Vactrol Multitype Filter Review

" I wanted to do this for a while. The thing about the A101-1 is that it can be aggressive and easy. Vactrols are known for their non-distorting response, combined with the Steiner design kinda gives a more tamable beast.
Also, Vactrols behavior is not always precisely predictable because of tolerances in each. Doepfer says:

"mechanical and electrical tolerances cause that each vactrol will behave a bit different (e.g. because of the differences in alignement and distance between LED and LDR, different brightness of the LEDs at the same current)"
This effectively means that A101-1 modules can sound slightly different than each other no matter what calibration is done.."

Uploaded by SoloStuff

Random Video: Doepfer A-100 Modular System w Legacy Filter Demo by LesIndes

Electronic Music Analog Synthesizer shop Les Indes from Berlin uploaded this long (almost 13 minutes) demo to YouTube.
The video mainly shows off the A-111 VCO and the (discontinued) Doepfer A-121 Multimode Filter...

Video: DOEPFER A-100 Modular System w Legacy Filter

" Featuring: High End VCO A-111 (running out of production), Multimode Filter A-121 (discontinued)"

Uploaded by LESINDES

On Facebook: https://www.facebook.com/les.indes.3

Doepfer A-106-5 Demo by Icaro Ferre

This one popped up on Vimeo a few weeks ago.

In a short video Icaro Ferre shows what the A-106-5 12db multimode SEM Filter module can do in multiple modes, and with different resonance settings...

Video: Doepfer A-106-5 Demo by Icaro Ferre
Doepfer A-106-5 Demo from Icaro Ferre on Vimeo.

" Running a sequence through the Doepfer A-106-5 SEM Filter module."

Uploaded by Icaro Ferre

on Twitter: Twitter.com/icaroferre

I have this module too, and I like it a lot.
The only thing i miss in this filter module is an extra CV input to control the resonance, just like the A-121 Multimode Filter or the other Oberheim filter, the A-122 24 dB Lowpass filter VCF3 have.

Doepfer A-121 Multimode Filter Tutorial Videos by Raul Pena

As promised, a new series of Raul Pena's excellent tutorial videos has started today.
This time Raul digs deep into, and explains all about one of my favorite filters, the Doepfer A-121 Multimode Filter.

Video 1: Doepfer A121 Multimode Filter Basics

" A brief look at the Doepfer A121 Multimode Filter. Basic Features and functions are discussed.
Audio demonstrations in the next video in the series.
Sound and Video by Raul Pena."

Video 2: Doepfer A121 Multimode Filter Low and High pass Filters Demonstration

" A brief look at the Doepfer A121 Multimode Filter.
Audio demonstrations of the Doepfer A121 Multimode filters.
A specific look at the Low and High Pass Filters. Next video in series looks at the Band Pass and Notch filters.
Sound and Video by Raul Pena."

Video 3: Doepfer A121 Multimode Filter- Band Pass and Notch filters Demonstration

" A brief look at the Doepfer A121 Multimode Filter. Audio demonstrations of the Doepfer A121 Multimode filters. A specific look at the Band pass and Notch Filters. Next video in series looks at Modulation of the filter.Sound and Video by Raul Pena."

Video 4: Doepfer A121 Multimode Filter- Modulation Demonstration

" Last segment in the Doepfer A121 Multimode filter series. Segment explores modulation of the A121 via the 1/V per octave inputs for frequency and resonance. 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