Monday, March 10, 2014

Doepfer A-127 BOM Filter Breakout Module Announced

Doepfer finally announced a few new modules for this year.
The first one is an expander-module for the A-127 Triple Voltage Controlled Resonance Filter, which has always been my favorite Doepfer filter...

Basically they took advantage of all the filter outputs that were already available in the original A-127 module, but not made available on the frontpanel.
I wrote about how i made my own A-127-expansion-board a few years ago in this blog, but this official board takes it to the next level, with even one more filter and separate audio outputs.

A-127 BOM Filter
Breakout Module
" For early summer 2014 the A-127 breakout module is planned.
This expansion module offers these new functions:
- additional notch filter for each sub-unit
- separate outputs for lowpass, highpass, bandpass and notch for each sub-unit
- separate audio input with attenuator for each sub-unit

The breakout module allows the separate use of each of the three A-127 filters.
In addition the filters can be patched parallel or serial.
Especially the serial connection of three notches generates very complex phasing-like structures.
For parallel filter connection the existing mixer of the main module may be used or an external mixer.
For serial connection the filters are patched in the desired sequence at the breakout module.
A jumper is used to define the filter type for each sub-unit for the mix unit of the main module.

The breakout module can be used without modification only in combination with the new version of the A-127 (pcb printing "Version 4").
Only the new version has the expansion connector available, that is required to connect the breakout module.
It's also possible to combine the breakout module with older versions of the A-127 (versions 1, 2 and 3) but in this case soldering is required to connect the breakout module to the main module (soldering 4 wires to each filter unit).

We will publish corresponding modification instructions as soon as the breakout module will be available."

You can still find my own A-127 DIY-expander blogposts via


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

Update May 23 2014: " The A-127 BOM is already in production and should be available July 2014."

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