Thursday, November 29, 2012

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

Wednesday, November 28, 2012

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.

Monday, November 26, 2012

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.

Friday, November 23, 2012

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:

Thursday, November 22, 2012

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."

Tuesday, November 20, 2012

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 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 (for Usergroup members)

Find more info at:
For those interested in the theory of operation, I recommend Tim Stinchcombe's page on this subject.

Sunday, November 18, 2012

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.

Friday, November 16, 2012

Eurorack String and Bow Interface by Peter Speer

As most of you know i have a special interest in alternative controllers and modules.
Earlier this year i posted the Guitar-module for example (can be found HERE)
Although there is not very much innovation in the Eurorack space lately, there are still enough DIY-ers with interesting ideas.

Check out Peter Speer's eurorack String and Bow interface for example.
It consists of a hollow laser cut MDF enclosure, with a guitar string pulled across two zither pins and a contact mic underneath (connected to the front jack).

The bow is homemade (2x4 + horsehair).

The video shows a nice demonstration.
" Pressure Points and the Wogglebug's Stepped Out (triggered by the Pressure Points) are controlling the frequency on the DPO, as well as the pitch shift on the Echophon.
The envelope out from an A-119 is opening the low pass gate on the output and controlling the modulation index on the DPO."

Video: Euro bow interface prototype

Check out Peter's 'Leisure Cove' blog at
And subscribe to his videos via Vimeo:

Thursday, November 15, 2012

Avoiding Hum From Power Supplies

If you are buying a second-hand rack, or if you already have a Doepfer modular rack with a cheap alternative (non-Doepfer) power supply you should be aware of how to avoid the (minor) transformer hum that cheap PSUs generate.

In the area near those power supplies (bottom right) no modules should be assembled that are sensitive to transformer hum.
Doepfer recommends to assemble only control voltage modules in this area (e.g. LFO, ADSR, trigger delay, clock divider/sequencer, sequencer, slew limiter, MIDI interfaces and so on)
,but no audio modules (VCO, VCF, VCA, VCP, frequency shifter, ring modulator, spring reverb and so on)
Also don't put the A-178 Theremin modules near the power supply.

Doepfer Power Supply I ( PSU I )
This matters for some of the cheap alternative non-Doepfer power supplies, and for the old Doepfer versions with PSU I 
For new A-100G3/G6 cases (with original PSU II) this does not apply. 

Find out how to distinguish the old transformer (PSU I) from the new version (PSU II) at

Sunday, November 11, 2012

Thursday, November 08, 2012

Doepfer A-117 Digital Noise/808 Source Tutorials by Raul Pena

Raul Pena is back with a brand new series, this time all about the Doepfer A-117 Digital Noise/808 Source.

Here is part one, the rest will be added here when they are published (every thursday).

Video 1: Doepfer A117 DNG Basics and Percussion
" Brief Description and Demonstration of the Doepfer A117 Digital Noise, Random Clock and 808 source. Demonstrations of how to create percussion sounds with this module.Sound and Video by Raul Pena."

Video 2: Doepfer A117 Playable Noise and Special FX

" Demonstration of "playable" noise using the Doepfer A-117 DNG. There is also a short demonstration of a Special Effect from the manual for the A-117. Sound and Video by Raul Pena."

Check out Raul's latest survey at
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

Tuesday, November 06, 2012

250th PatchPierre Post

Okay, it might seem a bit unnecessary to write a celebratory blogpost every 50th post, but it does feel like another milestone again.

I am happy to say the blog is still going strong after a relatively bad year for me personally, and glad that working on new blog-posts kept/keeps me distracted from all the negativity surrounding that.
Thank you so much again for all the support and the positive feedback.

I would like to share a few PatchPierre numbers with you about the PatchPierre universe:

- PatchPierre blog will reach the 75.000 pageviews this month, in a little over 2½ year.
- an average of around 5.000 pageviews per month lately, and this number is still climbing.
- Almost 1.100 people follow PatchPierre on Twitter

- Patchpierre.Net welcomed visitors from 126 countries

Top 10 countries  /  Pageviews
United States               17483
Netherlands                 10184
Germany                      6566
United Kingdom            5961
Russia                          4338
France                          2634
Italy                             1604
Canada                          806
Slovenia                         796
Ukraine                          522

Top 10 most visited posts                                               Date published

150th PatchPierre Post                                                     Dec 11, 2011
DIY Modular Case Ideas                                                     Jan 1, 2012
100th PatchPierre Post                                                    May 22, 2011
Vactrol Basics                                                                  Feb 21, 2011
Dark Energy II Announced                                                 Feb 7, 2012
50th PatchPierre Post                                                        Dec 7, 2010
Florian Schneider - Electronic Poem                                 Feb 19, 2012
200th PatchPierre Post                                                     May 6, 2012
CEM chips in Doepfer Modules                                        Feb 28, 2012

- Also more than 10.000 people downloaded and installed my free PatchPierre Mobile - Nokia app
  (more info at
- Almost 15.000 views of my YouTube videos at (subscribe!)

- I could use more likes on my Facebook page
- and donations (big or small) are still welcome via PayPal
  (info at
Donations will keep PatchPierre ad-free

Finding new topics is getting harder as i have already reviewed most of the Doepfer modules i own, but i hope i can keep the blog interesting enough in the future with a wider range of eurorack related posts.
If you have any suggestions / questions etc... feel free to contact me.

Thanks again for the support, regular posting returns this thursday with the start of a completely new Doepfer tutorial video series by Raul Pena!

Monday, November 05, 2012

Glow In The Dark Patch Cables

A nice way to pimp your eurorack;
Glow-in-the-dark patch cables by Expert Sleepers, the people who brought you Silent Way and more...

Video: Glow-in-the-dark patch cables

Available in 300mm, 500mm and 800mm lengths.
Order at

Saturday, November 03, 2012

Quick Tip X : The Warm Up

Good performances need a good preparation and a warm-up.
That does not only count for sports-prestations, but also for your (eurorack modular) analog synthesizer.

2 Doepfer VCOs that could use a good warm up
If you are looking for getting the best out of your Doepfer A-100, understand that you need to give your system at least 20 to 30 minutes to warm up.
If you don't give it that amount of time, the tuning can/will probably be (slightly) off.

To be clear, it's not a question of the "A-100" warming up, but of the modules installed.
In some cases, the warm-up period of a module is mentioned in the manual or on the web-page of the module in question.

Especially VCOs like A-110, A-111-1, A-111-5, A-143-4 need a warming-up to become stable and reliable.
If no warm-up period is mentioned the VCO is stable very soon (like the CEM3340-based A-111-1).

The PSU type (Doepfer power supply I or II) has no influence.

Thursday, November 01, 2012

Random Video: Kids on the Eurorack Modular

An 'oldie'... uploaded by machinate before i started my blog.
A combination of Eurorack (i see a lot of Doepfer) and kids.
Simply adorable...

Video: My kids on the EuroRack modular

Uploaded 27 aug 2009 by machinate