Doepfer A-124SE Special Edition Wasp Filter Module

A-124SE

Quite unexpected, Doepfer announced a black A-124 Wasp filter with yellow knobs today.

This module comes as a limited edition and will be available through your local dealers. (order no. A-124SE)
According to a Doepfer interview with the Sud-Deutsche Zeitung the first batch sold out (to distributors) within 24 hour.

Great marketing-idea by Doepfer IMO, especially to promote the recently announced colored knobs. All kinds of color-schemes are possible now.

I hope they will do that to more modules...

Find out more about the A-124 Wasp filter at http://patchpierre.blogspot.nl/search/label/A-124

Random Video: Modular Synth - A-143-4 and A-149-1 Orchestral(ish) Sounds by IsVisible

Here's the latest modular synth video by IsVisible.
It's kind of orchestral-ish and features Doepfer's A-143-4 and A-149-1 modules.

Video: Modular Synth - A-143-4 and A-149-1 - Orchestral(ish) Sounds
Modular Synth - A-143-4 and A-149-1 - Orchestral(ish) Sounds from isvisible on Vimeo.

" Here we have the Doepfer A-143-4 Quad VC/LFO/VCO triggering the A-149-1 Random Voltages. The A-143-4 is also triggering the A-143-2 Quad ADSR along with providing a little cv to the A-110 VCO's.
All in all with a little filtering courtesy of the A-106-1 Xtreme Filter (Korg MS-20 inspired) and the A-124 Wasp (erm... a Wasp clone) it sounds a bit orchestral, in an abstract kinda way anyway.
Both line outs from the modular (bassier / brassier low end and plucked / reedish higher end) are going directly into a lovely old Tapco 4400 Dual Reverberation System then to my mixing desk where the audio is taken from."

Follow IsVisible on Twitter at https://twitter.com/isvisible

More IsVisibe at http://www.isvisible.co.uk/

Also check out his new album vii. http://isvisible.bandcamp.com/album/vii  - free to download, or pay what you like if you feel the need.

Doepfer A-124 WASP Filter Simple Sweeps Demo by MylarMelodies

MylarMelodies (formerly known as Cymatic and MusikMesse 2012-picture-provider for PatchPierre.Net) has uploaded a nice video showing off his Doepfer A-124 WASP filter.

It's one of my favorite filters, so it's not really a surprise he likes it too...

Video: Doepfer A-124 Wasp Filter Simple Sweeps Demo.

"Being a video that shows the Doepfer Wasp Filter's character off on some simple square waves. Modular signal is processed with a tiny touch of UAD EMT-140 Plate Reverb to take the edge of its dryness. " 

Check out the rest of his music at mylarmelodies.com and his blog at http://howdoyoumakemusic.tumblr.com

Also check out the easy modifications for A-124 self-oscillation HERE and HERE

Modifying the A-124 Wasp Filter a Little More

I don't know why i didn't come up with this idea earlier, but here is a short follow-up to my earlier self-oscillation modification post for the A-124 WASP filter ( original post can be found HERE )

The (mini-) modification consists of adding a switch to toggle between self-oscillation on/off modes.
To do this i had to use an extra 4 HP wide blank panel because there isn't enough space left on the A-124's front-panel to add a switch.
This is not my first 'expansion module',
i  made one earlier for my A-127 Triple Resonance Filter

I did this modification in less than an hour; i carefully drilled a 6 mm. hole in a new 4HP blank panel, desoldered one side of the resistor that i added earlier and connected that one to the new switch.
Another piece of wire connects the other side of the switch back to the original position of where the resistor was connected.

I am very happy with the result, i can now manually switch, turn the resonance-knob up to self-oscillation and simply switch back to the original mode again...

Thanks to Tony Steventon from Synovatron for the project review

Modifying the A-124 Wasp Filter for self-oscillation

Out of the box the A-124 Wasp filter can not go into self oscillation, in contrast to most of the other filters in the A-100 system.
Lucky for us modifying the module for self-oscillation is quite easy;
Doepfer's DIY page tells us that;

"Soldering a 10k resistor in parallel to R13 (27k) leads to self-oscillation of the filter at the max. resonance setting of the resonance control."

Locating the R13 resistor was perhaps the most difficult part of the job. Because the resistors are all soldered on the PCB very tightly it is hard to read what the printing on the board says about the mounted resistors... but i found it!

Locating the R13 resistor

R13 is located in the gap between IC1 (CD4069) and IC2 (i.e. the upper CA3080, close to C4/100pF). See picture above.

I did have a few spare parts lying around, including a 10k resistor. Soldering in parallel in this case was very simple. I did this on the backside of the PCB.

After locating the correct resistor you can simply solder the new resistor on the other side of it. Not much can go wrong.

Just be aware that your soldering-iron doesn't overheat or burn your resistor.

I read mixed reviews of this modification, but you have to remind yourself that the A-124 itself acts kinda unpredictable in the first place, due to the design that "abuses" digital inverters as analog operational amplifiers leading to distortions and other "dirty" effects.

A post-modification audio demo by Madrayken ( Dene Carter ) can be found HERE

 WaspPostMod by Madrayken 

Filters III : A-124 Wasp Filter

The A-124 is a special 12dB multimode filter using the filter circuit of the EDP Wasp, a monophonic black and yellow analog synthesizer, that was built around the end of the seventies and manufactured by the UK company Electronic Dream Plant.

I totally love the sound of the A-124 Wasp Filter module. It does have it's own special sound due to the special circuits in it which makes the module sound a little dirty and distorted. This can sound very nice with extreme filtersweeps, i often control the cut-off frequency with the pressure CV from the A-198 Ribbon Controller.

The module has 2 audio outputs; a band-pass and a combined low/notch/high pass output that can be controlled with the 'mix' knob that defines the relative amounts of low and high pass signals.
( middle position is notch )

One downside of the module is the lack of a QCV input like most A-100 filters have, so sadly the Resonance cannot be controlled via an external voltage. You can only adjust this manually.
It would have been nice if the Mix could also be controlled by CV...   IMHO

Out of the box this filter can't go into self oscillation, in contrast to most of the other filters in the A-100 system, but modifying  for self-oscillation is quite easy;

Soldering a 10k resistor in parallel to R13 (27k) leads to self-oscillation of the filter at the max. resonance setting of the resonance control.*

 More info on this modification can be found HERE