Showing posts with label A-127. Show all posts
Showing posts with label A-127. Show all posts

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.

Remark:
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 http://patchpierre.blogspot.nl/2010/12/modifications-ii-127-triple-resonance.html

Source: http://www.doepfer.de/a127.htm

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."

Thursday, April 11, 2013

Doepfer A-127 VCRF Re-Design

I almost missed this between all Doepfer's other MusikMesse announcements;
As of April 2013 the Voltage Controlled Resonance Filter A-127 is available in an improved version.
Instead of the CA3080 chip (not available anymore) that was used in the original versions, new high-end circuits (SSM2164) are now used.

Doepfer A-127 Triple Voltage Controlled Resonance Filter
"The SSM2164 chip contains four independent voltage controlled amplifiers (VCAs) in a single package. High performance (100 dB dynamic range, 0.02% THD) is provided at a very low cost-per-VCA, resulting in excellent value for cost sensitive gain control applications.
Each VCA offers current input and output for maximum design flexibility, and a ground referenced -33 mV/dB control port."

A-127 + Expander
This is probably the Doepfer filter that i use the most, and the brand new re-design also promises to reduces the noise floor and the distortion clearly, according to Doepfer.
(The noise that i never really noticed before...)

The price of the new A-127 VCRF remains unchanged.

Check out how to make an A-127 expander module HERE.

Friday, June 01, 2012

New Doepfer Re-Designs Due to CA3080 Shortage


After the unplanned re-design of the Dark Energy (due to the unavailability of the CEM3394 chip ) there now seem to be more re-designs of Doepfer Modules coming up.

This time the problem is the availability of CA3080 (and 3080E) chips.
The CA3080 (datasheet PDF) is a 2MHz Operational Trans-conductance Amplifier (OTA), which is used in quite a few Doepfer (and other brands) modules and there seems to be no direct replacement equivalent.
The original chip itself hasn't been produced since 1975 and the wafers have all been used up a couple of years ago, according to some sources.
No-one seems to have decent stock anymore, and there was a buying craze when it went out of production.

That does mean that some Doepfer modules have to be re-designed in the near future because of this obsolete integrated circuit ( like the A-107, A-116, A-127, A-130, A-131, A-132-1, A-141, A-142-1, A-147, A-171). 

This will take a lot of precious time for Doepfer that would otherwise be spent on manufacturing new modules.
Sadly these re-designs will not have any obvious benefit for the customers.

Thursday, May 24, 2012

A-127 Triple VC Resonance Filter Videos by Raul Pena

Raul Pena (from http://raulsworldofsynths.com/ ) has published the four A-127 Triple Voltage Controlled Resonant Filter tutorial demo's.
As most of you already know, this is one of my most favorite Doepfer filters, see more of my posts about this module HERE, so i was kinda looking forward to these video's.

Video 1: Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter Part One-Introduction

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter.Focus on Basic Features. One of four videos. Next in series Modulation.
Audio Loops by Raul Pena.Sound and Video by Raul Pena."

Video 2: Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter Part Two-Modulation

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter. Focus on Modulation of Resonant Filters. Number Two of four videos. Next in series More Modulation.
Audio Loops by Raul Pena. Sound and Video by Raul Pena."

Video 3: Doepfer A127 Triple Voltage Controlled Resonant Filter Part Three-More Modulation

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter.Focus on Modulation of Resonant Filters by Sample and Hold.
Number Three of four videos. Next in series Audio Rate Modulation.
Audio Loops by Raul Pena. Sound and Video by Raul Pena."

Video 4: Doepfer A127 Triple Voltage Controlled Resonant Filter Part Four-Audio Rate Modulation

" Description and Demonstration of the Doepfer A127 VCRF Triple Voltage Controlled Resonant Filter.Focus on Audio Rate Modulation of Resonant Filters.Demonstration of audio distortion with the A127.Number four of four videos.Audio Loops by Raul Pena.Sound and Video by Raul Pena. "

Tuesday, December 21, 2010

Modifications III : A-127 Triple Resonance Filter Expander (part 2)

Hmmm... that went faster as i expected.
My brand new self-made A-127 Expander Module is now almost finished.
( Find part 1 HERE)
The switches are wired too, and the overall look of the module is even better as expected.

I did have some trouble with drilling holes through the aluminium front-plate at first, but it seems i aligned the sockets nice enough with the output sockets of the A-127 itself.
The switches work smoothly and the 'new' 12 dB filters sound sweeeeeet.

I'm very happy with this module, and glad that i went with this option instead of just putting switches on the A-127's front panel.


The wiring of the modules on the backside was quite simple. Red wires were used for switching between the different filter-modes, the blue ones the the audio-multipliers, and yellow ones (not visible in the picture) for the lower switch.
I did the soldering without removing anything from the module, but you might want to remove some components for easier access.

Instead of soldering you can also use small (0.1") wire-sockets at the board's jumper-spots. An example with detailed information of this can be found HERE

Update March 10, 2014
Doepfer announced an official Breakout Module for the A-127,
find out all about it at http://patchpierre.blogspot.nl/2014/03/doepfer-127-bom-filter-breakout-module.html

Monday, December 20, 2010

Modifications II : A-127 Triple Resonance Filter Expander

Now that i finished my first 'real' module-modification i couldn't wait to start with the next project.
At first i wanted to replace a red LED for a blue one on one of my modules myself, but i couldn't decide which module i should pick for this... and i'm still not sure, but that can wait....

Another plan that was in my head from the beginning was the placing of 3 switches on the front-plate of my A-127 Triple Resonance Filter. There are 3 jumpers inside this module that allow the user to switch the filter-type of each of the three channels between Band-Pass (standard) and 12 dB Low-Pass. I have seen some examples on the web of this modification, most of them just with the switches mounted on the A-127 itself, but unexperienced as i am, i was too afraid to damage the front-panel and went for an Expander Module design.

So that is why i am building it into an official 4HP blind-panel that i bought from Doepfer. Each of the three A-127 channels on my expander module design will have a switch to switch the channel's filter-mode and will also provide an extra (linked) audio output.
( mainly to fill up the space, but i aligned these with the A-127's original outputs to make it look more like an official Doepfer module ) .

To complete the expander module i also want to place a switch at the bottom that has the function of the J3 jumper that is inside the A-127 module on the mix circuit-board. This switch can put the module in a mode so that both levels of the filter and the original can be controlled with attenuator 1 ( audio level in )

I am not finished with the project yet, the mounting of the switches and extra outputs is done. Wiring is the next step, i'll write another post on that later this week...
Find Part 2 at http://patchpierre.blogspot.nl/2010/12/modifications-iii-127-triple-resonance.html


Update March 10, 2014
Doepfer announced an official Breakout Module for the A-127,
find out all about it at http://patchpierre.blogspot.nl/2014/03/doepfer-127-bom-filter-breakout-module.html

Saturday, November 20, 2010

Filters I : A-127 Triple Voltage Controlled Resonance Filter


It is hard to say what my favorite A-100 filter is. Every filter has its own distinctive sound, and they all have a lot of Control Voltage input possibilities. I must admit i prefer low-pass filters... and filters with many outputs.

The A-127 VC Triple Resonance Filter is 3 bandpass-filters in one, each with its own LFO (sine) with adjustable frequency. The module has 3 individually adjustable outputs plus a mix output, and with all the controls for filter frequency and resonance it is a very flexible module.
\All 3 filters have an external CV input too, that by-passes the LFO when a plug is inserted in the socket. The amount of incoming CV's can be attenuated with a knob.

I love the sound of it, one of the characteristics of the 12 dB/Octave filters is that it can produce almost vowel-like sounds.
The LFO's can create amazing filter-sweeps as well with the frequency-rate adjuster.
As modulation inputs various CV's can be used like ADSR's and other LFO's (triangle/saw/rev saw).
Inputting voltages from any Wheel, Joystick or Theremin modules are also awesome ways to control this massive module.

You can even turn this module into a Triple Low-Pass Filter by changing internal jumpers, another nice feature. It might not be my most favorite filter of all, but this one is still the most-used filter that i own at the moment...