Random Video: Random Melody #121227

I found this one on a new YouTube channel today,
a nice random sequence on a large eurorack synthesizer with mainly Doepfer modules.
Very cool...
The channel promises "Electronic Synthetic Music, Bleeps & Noise.", and i'm already looking forward to more videos.

Video: Random Melody #121227

" Late night random melody patch."

Uploaded by AsteroidKillerMusic

A-136 Pre-amp Modification

I discovered another nice light-weight DIY-project on the Doepfer DIY-page.

Locating the R2 resistor

It seems that the A-136 Distortion/Waveshaper module contains an internal pre-amplifier that is used to amplify the input signal by about 3.5 before it is processed by the A-136.
Especially for low level audio signals (e.g. output from a VCF) this is useful.

But for all signals with a level beyond ~ 7V this causes clipping before the internal processing takes place. 

Especially for the processing of LFOs or unfiltered VCOs this may cause a problem.

The wiring, additional pictures
on the PatchPierre Facebook page

To totally bypass the internal pre-amplifier, resistor R2 can be removed (e.g. by pinching off).

R2 is the resistor in the upper third of the pcb which is very close to the rear edge.
When R2 is removed the amplification of the internal pre-amplifier becomes "1" (which means that it does no longer amplify).

Finished modified A-136 

Because i love to keep myself busy (I'm slightly ADD-ish), i decided to add a switch to the module, so i can switch between pre-amplifier on and off modes.
It looked like an easy project, so... what could go wrong? ;-)

Besides the front-panel it was a pretty easy job;
I desoldered one side of the R2 resistor, bent it over towards the switch, and wired it with black wire.
After that i soldered another wire (red) from the switch to the hole where R2 used to be. Easy as that.

Now i can manually switch the internal amplifier on and off when required.
The clipping did annoy me at times and now i prevent that and try the un-amplified signal with alternate settings*.
it's not a groundbreaking project, but a nice extra.

* In addition one has to pay attention that the knob positions may vary a bit from the front panel printing because of mechanical tolerances of the potentiometers and knobs (i.e. "0" is not always exactly the neutral position for "A", "+A" or "-A")

The modifications described on this site will most likely void any warranty and, if not done carefully, can damage the circuit board, IC chips, and faceplates.
PatchPierre can not be held responsible for any damage.

How NOT to Modify

The rail is still visible through the
new hole i drilled

Okay... sometimes you have to learn the hard way.

I made a slight mistake while drilling a new hole in a front panel for my latest DIY-project.
(blogpost will follow soon)

Although i knew there was not a lot space where i had to drill, i did not calculate that the rail would still be visible.

Hardly visible, but i had to scrape almost
one mm. off the module's PCB

I am glad that i didn't have to put a mini jack connector but only a switch there, but that didn't even fit here.
Okay, maybe I should have drilled a smaller hole in the first place.

My bad... but still very annoying.
On the other side of the hole there's the module's PCB, so i couldn't put the switch higher without also modifying the PCB board.

Luckily i could solve the problem with an extra large ring.
It has not trned out to be my most successful modification.
More info on what i was working on will follow later this week.

Finished switch, with extra large ring

Sadly i also damaged the front-panel a little bit (bottom left and under the D from Doepfer)

I should be more careful next time, and take a little bit more time for my modifications... 

Make a plan first... and work step-by-step.

That would spare me a lot of trouble.

New Doepfer Announcements

Doepfer released preliminary information about two new modules.

The A-190-8 is a MIDI/USB to Sync interface.
Basically this module divides the incoming MIDI or USB clock messages into smaller steps.
You could see it as a modular version of the MSY2 MIDI-to-SYNC Converter that was announced in December last year, but with multiple simultaneous outputs and added USB support.
Funny that i already posted my idea for a module like this in late 2010 (Read that blogpost HERE)

A-190-8 Prototype 1

The main application of the module is the control of clocked A-100 modules like sequencers, sequencer controllers, trigger divider, trigger sequencer and similar units, but also to trigger/reset LFO's, envelope generators and more.

The A-190-8 will have 10 available outputs which are not yet fixed. 

Preliminary info can be found HERE, and if the users think other combinations of clocks or start/stop/reset outputs would be better, Doepfer can change that because the outputs are generated by the firmware of the processor.

Read some of the user suggestions at the Doepfer Yahoo Usergroup.

Doepfer left out the usual DIN SYNC socket because to create that you only need clock and start/stop on two pins of the DIN socket. 

If there are sufficient inquiries Doepfer may offer a special cable with two 3.5 jack plugs on one side and a DIN plug on the other. 

(For example to synchronize a TB-303)

A-180 Multiples and
a 2 HP blindplate,
the size of
the new A-180-2

For early in 2013 also a slim version of the A-180 Multiples module is planned.

This will be called A-180-2 and will be half the size of a regular A-180.

Because of the only 2 HP width nuts cannot be used to mount the pc board by means of the socket nuts at the front panel. 

Instead of that the PC board is mounted by screws and spacers at the front panel.(pic)

Personally i don't think i want one of those in my system because of how a nut-less module looks, but i can imagine there are people who applaud space-saving modules like this.

There were also a few other announcements/updates:
In December the A-192-2 (Dual CV/Gate-to-USB/Midi interface) will be available and even the hardware of the Polyphonic CV/Gate interface A-190-5 is ready.
"Christian (Assall) is about to program the firmware. But it takes longer than expected  and so the A-190-5 will be available early in 2013."

Special thanks to Bakis Sirros in the Doepfer Usergroup for sharing parts of this info.
Bakis can be found via multiple ways, support him and his band(s) to help the Greece economy a bit:

www.parallel-worlds-music.com
www.facebook.com/pages/Parallel-Worlds/192093934136476
www.myspace.com/interconnectedmusic
www.myspace.com/memorygeist
www.DiN.org.uk
www.vu-us.com

Doepfer A-106-1 Xtreme Filter Tutorials by Raul Pena

Raul Pena is back with a new video tutorial series, this time all about the A-106-1 Xtreme Filter.

Here are the first two, of four... 

Video 1: Doepfer A106-1 Xtreme Filter Basics

" A brief description of the features and functions of the Doepfer A106-1 Xtreme filter.
This filter is similar to the filter in the Korg MS20 but has its own unique character. Sound and Video by Raul Pena."

Video 2: Doepfer A1061 Xtreme Lowpass/Highpass Filter Audio Demonstration

"A look at an audio demonstration of the basic features of the Doepfer A106-1 Xtreme Lowpass/Highpass Filter. Sound and Video by Raul Pena."

Video 3: Doepfer A106-1 Xtreme Lowpass/Highpass Filter Modulation and Resonance Part One

" Audio Demonstration of Modulation and using the resonance insert of the Doepfer A106-1 Xtreme Lowpass/Highpass Filter. Sound and Video by Raul Pena."

Video 4:
Doepfer A106 Xtreme Lowpass/Highpass Filter Modulation and Resonance Part Two

" Part Two of an Audio Demonstration of Modulation and using the resonance insert of the Doepfer A106-1 Xtreme Lowpass/Highpass Filter. 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

Doepfer Usergroup Poll: Voltage Controlled Slope Module

Recently Dieter Doepfer ordered a new poll in the Doepfer A-100 Usergroup.
It looks like he is seriously considering a 'Serge Voltage Controlled Slope' -inspired A-100 module.
If there is enough positive feedback it will be manufactured with the license of the copyright owners of the Serge module ( and it may also have the additions that Ken stone has designed).
Because of the license fee, the module's price will be a bit higher than standard A-100 modules.

Bananalogue Serge VCS PCB

In the early 1970s, Serge Tcherepnin developed the Positive Slew and Negative Slew modules for the original Serge synthesizer.
In time these merged into the classic Dual Universal Slope Generator.(Vimeo link with video)

For example;
The Serge VCS module, (re-)released in conjunction with bananalogue.com was/is an extremely versatile control voltage generator and audio source.
The Bananalogue VCS and CGS75 are both an adaptation of Serge's original circuit with a few new features.
At first glance it seems to be a VC slew limiter but after a closer look you can discover a very versatile module which can be used as a VC-LFO, VCO, AR-envelope, VCF, envelope follower, waveshaper, subharmonic and a trigger delay.

That's nine functions in one module!
It is not sure which functions the Doepfer module will have, but i guess they will try to get the most out of it.

So, the question in the Usergroup is:
" Would you buy a Doepfer A100 'Serge Voltage Controlled Slope' inspired module? "

The poll will remain open for one month, until 19th of December.
Voting is possible at http://launch.groups.yahoo.com/group/Doepfer_a100/surveys?id=13160415 (for Usergroup members)

Find more info at:
http://web.archive.org/web/20080224013413/www.bananalogue.com/vcs.html
For those interested in the theory of operation, I recommend Tim Stinchcombe's page on this subject.

Doepfer MCV-24 Battery Replacement

Zoë Blade's partner Nina Richards has made an interesting short video demonstrating how to replace the Doepfer MCV-24's internal battery.

Video: Doepfer MCV-24 battery replacement

" Nina's short guide to replacing the internal battery of a Doepfer MCV-24"

Uploaded by Zoë Blade

The following Doepfer devices are (or have been) equipped with a rechargeable battery like this for memory backup:
2.4V rechargeable battery: LMK3/LMK3+
3.6V rechargeable battery, grid 10 x 20 mm.: used in d3c, MCV24, A-112 VC Sampler /Wavetable Oscillator, Schaltwerk and Regelwerk.

Find more info on Doepfer batteries at http://patchpierre.blogspot.nl/2011/09/quick-tip-vii-battery-check.html