Random Video: TheVoltageControl's Doepfer A-100 Modular System

I spotted this nice Doepfer Modular video on the always interesting http://voltagecontrol.blogspot.se/ blog.
It is exactly what the accompanying text says... a short demo of his current Doepfer system.

Video: Doepfer Modular System

" A short demo of my current Doepfer modular system.
http://voltagecontrol.blogspot.se"

Uploaded by TheVoltageControl on YouTube

Doepfer Power Supplies

There are 2 types of transformers used in the existing standard Doepfer A-100 racks and cases.

The old Doepfer power supply with a
rectangular transformer

If you are buying a secondhand A-100 rack, it might be useful to know how to distinguish the old transformer from the new version.

The newer version is a better version, more reliable and provides a steadier voltage that is better for your system, although i personally never heard any complaints about the old transformer besides the longer warming-up time.

The old power supply has a black or blue rectangular transformer, where the new power supplies have a round silver transformer.

The new Doepfer power supply with a round transformer

For a period during the transition (about 2 years) the customers could order both versions.
In any case all A-100 cases manufactured later than early 2005 are equipped with the new power supply, and all cases manufactured until about of 2002 are equipped with the old version.
For cases manufactured in 2003 and 2004 it depends which version has been ordered by the customer.

In any case the new power supply can be identified by a small label outside the case near the mains inlet.
It says "Power Supply II" unless it was removed by the user.

Source: Dieter Doepfer

Locating the A-100 Fuse

The fuse-box is located between the
power inlet and the on/off switch

It's pretty basic, but every once in a while i receive the question: "Where can i find the fuse on my Doepfer rack?"
I must admit i had to search for it too the first time i blew up a fuse.

The answer is quite easy.
On the backside of the G6 rack (and G3 rack and most other cases and koffers) you'll find the power supply and the On/Off switch.
Between these two there is a small compartment where the fuse can be found.

Use a small screwdriver to
slide out the fuse-holder

Always remove the power-cord before you are opening the fuse-box!

With a small screwdriver you can gently pull this fuse-box out of it's place and replace your A-100 fuse.
Check out the Doepfer FAQ to see what fuse-value you should use in your rack, depending on rack-size and country.

Fuse-holder with A-100 fuse

Big A-100 Book by Andreas Krebs Delayed

Sad news for some of the non-German-speaking A-100 fans;

The original German version
of the big A-100 book by Andreas Krebs

Das Grosse Buch zum Doepfer A-100 Modular-Synthesizer, the German A-100 by Andreas Krebs that was published half a year ago (also check my earlier BookTips) will probably not be available this year yet.
I recently contacted him about a possible release-date of the (pre-announced) English version, but he replied that the project is delayed.

He wrote: " There had been plans to release the book end of this year. However, there have been some big delays in this project due to personal reasons (currently we’re moving from Munich to the countryside).
I hope to be able to put some more efforts on the english version as soon as we have moved and everything is “in its place” again."

I hope his situation will improve soon...

The German version is still available;
Price: Euro 29,90 € plus shipping
Find more info and ordering details at: http://www.ideenhase.de/html/doepferbuch.html
German version is also available via Doepfer

Re-arranging my A-100 System

Last weekend i finally had some time to re-arrange my A-100 system.
I seems like this just has to happen every  few years...
It's was dirty job... a lot of screwing had to be done...

The main problem was the (old) location of my vocoder system, i had it in the middle of my rack.
That meant that i had a lot of wires hanging over the modules in the row below it.
I took out the vocoder modules and placed them at the bottom row.

My Joystick/Voltage inverter combo, the Modulation Wheels and the Manual Trigger modules were replaced to where the vocoder used to be, for maximum real-time control from the center of my setup.

The top three rows stayed the same, with mainly oscillators, noise mixers and filters (plus the 2 Theremin modules).
In row 4 i placed an extra A-180 Multiples next to my Quad ADSR so i can easily send multiple envelopes through my rack.
The rows below that have an assortment of various modules; LFO's, Distortion, Waveshaper, BBD and Frequency-shifter, to name a few... and my Trigger Sequencer, Divider, Inverters and Logic Modules.

At the lowest two rows on the left you'll find my inseparable section of modules from where i can switch playing-modes between Ribbon Controlled or by Keyboard (MIDI)-controlled... find and extensive post about this section HERE.

The Vocoder and its cables that were causing the main problem.
Note the frequency displacement

CEM chips in Doepfer Modules

After the announcement of the discontinuation of the Dark Energy due to a lack of CEM3394 chips I started  making a basic inventory on what CEM chips were used in which Doepfer Module.

The A-111 VCO2 (discontinued) used one CEM3340

The list is still far from complete, also because there are still many Doepfer modules that i don't own, but i am hoping to be able to crowd-source the rest this way.

Feel free to help me complete the list by posting your findings in the comments or by mailing me your additional info, thank you all in advance.

A-121 Multi Mode Filter / A-122 Low Pass Filter:     CEM3320

 A123 High Pass Filter / A-179 Light Controlled Voltage Source:     CEM3320

A-111-1 High End VCO:     CEM3340

A-132-3 DVCA Dual Linear/Exponential VCA:     CEM3360

A-107 Morph. Filter:     CEM3379

A-124 Wasp Filter / A-106-6 XP Filter:     CEM3379

A-109 VC Signal Processor:     CEM3379
*Newer versions of the A-122 Low Pass Filter VCF3:     CEM3379

A-130 VCA (linear) / A-131 VCA (exp.) / A-134 VC Panning:     CEM3381

A-126 Frequency Shifter:     CEM3382

A-111-5 Mini Synthesizer Voice:     CEM3394

Dark Energy , Monophonic Synthesizer:     CEM3394

Sources and more info on what chip is inside your synthesizer:
http://curtiselectromusic.com/,
http://synthtech.com/cems.html and http://www.synthtech.com/cem/cemdata.html
http://sequencer.de/synth/index.php/Chips_in_Synthesizers

Note: Not only CEM chips are used in Doepfer modules, i am also working on a full inventory including Texas Instruments chips and as many others as possible. Feel free to contribute...
Thanks to contributors: George P. Macklin, Jakobsweb...

Florian Schneider - Electronic Poem

Here's another classic from the web that caught my attention last month, and it has an interesting story behind it too...

The (audio-) recording in the video below originally comes from a KEYS-Magazine demo CD, Issue 04 / 1996.
This issue of the magazine had an extensive A-100 test (page 44-50) in it, with statements from Kraftwerk's Florian Schneider (and O. Lieb).
Kraftwerk had worked intensively with Doepfer in the mid- nineties, for example on the Doepfer Mogli 'Midi Output GLove Interface', the MAQ 16/3 sequencer, the Doepfer A-129 Vocoder and some other (custom and modification) -projects. (more on this next month)

Florian Schneider (from Kraftwerk) spoke this poem on the answering machine of Florian Anwander, who wrote for the German KEYS magazine at the time.
Anwander played the cassette of the answering machine back in a Fostex 280 multitrack deck and did the vocoder recording with a straight saw wave from a Roland JX3P synthesizer as a carrier-signal.
No voiced/unvoiced detector was used; instead of that he took the high frequencies of the original signal, that were later added to the output-signal.

A Yamaha 2020 compressor and a noise-gate from Ashley were also used in this audiorecording.

Florian Schneider (Kraftwerk)
and Dieter Doepfer *

" Analogsynthese mit system 

klanglich, optish angenehm

technisch, logisch, funktionell

prototypisch und speziell

modular und variabel

leicht, kompakt und transportabel

für ein musikabenteuer

A-100, nicht zu teuer

midi-kontrolle vom computer

A-100 to the future! "

-translated into English:
Analog synthesis system / sonically and optically pleasing / technical, logical, functional / prototypical and special / modular and variable / Light, compact and portable / for a musical adventure / A-100, not too expensive / midi control from the computer / A-100 to the Future!

Video: Enigmidia / Florian Schneider - Electronic Poem
http://www.youtube.com/watch?v=B-gp5x1ujME
" Doepfer Vocoder, Digital ComputerArt by Paulo R. C. Barros
Florian Schneider, from Kraftwerk, perform a recorded test-drive of a vocoder to the Doepfer electronic instruments."

Florian Schneider seemed to be very pleased with the A-100, on page 45 of the KEYS-issue he writes:
" Up to now, I only had the chance to play around for one day with the A-100, but I can already say that Doepfer has built something really special.
The system does sound very good and does offer everything I do expect from a modular system - and that at a really reasonable price.
For me it is also a plus that it has turned out smaller than other systems, like some may point out.
But the adjustors on a mixing desk are even closer together, and you can also take it with you easily and leave the expensive rarities at home.
The vocoder has turned out really nice; it does really sound good in comparison to other vocoders.
After building a multi-channel filter (a very important module, by the way), it was only a small step for Dieter Doepfer to combine this with VCA's and Envelope-followers. "

He also shared a tip;
" On a modular synth, you really learn how the sounds are made.
I can advise anyone to buy a simple oscilloscope with the modular system.
This was also my start, I was fascinated to see; "this is how the sound looks here and after the filter it looks like that...".
You can really see principles here which you can also find in the whole world. "

* The opening voice is Gia Stemmer, who did the moderation of the KEYS demo-CD.
More info on the Doepfer vocoder system HERE

* Picture from Doepfer.de

Random Video: Doepfer A-100 Modular Madness 1 by Frequenzverschiebung

A new A-100 video that caught my eye today is this next one by YouTube user Frequenzverschiebung, simply called 'Doepfer A-100 Modular Madness 1'



" Random Doepfer A-100 patch, all movement controlled by two LFO modules (A-145, A-146) and noise, S&H (A-118, A-148), SSM2044 filter (A-105), ring mod (A-114), 2 VCO (A-110) and more.

Additional delay and reverb with software plugins ValhallaÜberMod and ValhallaRoom. "

Subscribe to his YouTube channel at http://www.youtube.com/user/Frequenzverschiebung

Discontinued A-100 Modules

Good things come and good things go...
There are many different reasons for manufacturers to stop producing certain modules.
Sadly for some people, some components of a few Doepfer modules aren't available anymore.
Some of the special circuits ( or IC's) in the modules have become scarce, or not available at all ( like the original knobs ) , and that has been a reason for Doepfer to discontinue the production of some of these modules.

Another reason to stop producing certain modules is because they just don't or didn't sell... maybe just because they are not very useful (anymore) or they disappeared when newer modules appeared with (almost) the same function(s).

Soon a collector's item?

An overview ( updated February 2012 ) :

A-111 High End VCO  As the special circuit CEM3340 used in this module is no longer available the module has to be discontinued.
/ Sale while stocks last.

A-121 Multimode Filter As the special circuit CEM3320 used in this module is no longer available the module has to be discontinued soon.
/ Sale while stocks last (only 20 left in Januari 2012)
Doepfer recommends the A-106-6 XP VCF, that is based on the filter circuit of the Oberheim Xpander, as a replacement module.

...the A-101-9 Universal Vactrol Controller is the latest addition to the running out/ sale while stock lasts list... more info on this later

The A-111-5 Mini Synth Voice (and the Dark Energy) will also be discontinued because of CEM3394 chip running out... Stock is still available.
More info on this HERE

The following Doepfer modules are not available anymore:

A-123 24dB High Pass was discontinued at the time by poor sales, and the special circuit CEM3320 used in this module is no longer available.

...and another one...

A-126 Frequency Shifter Because the special circuit CEM3382 used in the internal quadrature VCO of the A-126 is no longer available Doepfer had stop the production of this module too.
But they are about to plan a succeeding model ( A-126-2 ) without internal VCO. The advantage of this solution is that even frequencies below 50Hz are available for special beat effects based of frequency shifting at low frequencies.

A-138x Mix Expander - Because of the poor inquiries the production of this module had been stopped too.

A-139 Headphone Amplifier, a 2-channel headphone amplifier with 2 audio inputs (3.5 mm jack sockets) and level controls, common loudness/master level control, 2 headphone outputs (stereo 1/4" jack sockets) - no longer available

A-177 External Foot Controller is now replaced by the A-177-2, a more economical replacement with a little less control (without LEDs and without scale controls), but with almost the same functions.

A-179 Light Controlled Voltage Source is also no longer available as the special circuit CEM3320 used in this module is no longer available. That is why this module also had to be discontinued.

A-191 MIDI-to-CV Interface / Shepard Generator no longer available

A-197 Analog Meter no longer available ( i personally never really expected an analog meter to be very useful, and i guess i wasn't the only one )

A-197-2 Oscilloscope kit no longer available -
I am still looking for an affordable oscilloscope though. I was thinking about something like a MFB VD-01 Videoscope, but sadly there's no budget at the moment...

Latest update: A-188-1Y BBD Module (256 stages) is also on sale while stocks last


Curious what chip is inside your synthesizer?
Check http://synthtech.com/cems.html and
http://sequencer.de/synth/index.php/Chips_in_Synthesizers

How To Hide an Arpeggiator

An arpeggiator is a feature available on some synthesizers that automatically steps through a sequence of notes based on an input chord, thus creating an arpeggio.

One of my biggest personal complaints about the 'original' A-190 MIDI-CV Interface was the fact that the front-plate had the text 'arpeg.' on it while an arpeggiator function wasn't even implemented (and still not) in this module.

Doepfer recently stated that "...there were plans to add an arpeggiator when the module was designed about 15 years ago. But we found that the processor power is not sufficient to add this feature..."
He also stated that the new A-190-3 USB/Midi-to-CV module does have an arpeggiator available. ( the A-190-3 is the modular version of the Dark Link and Dark Energy USB/Midi interface, watch an 8-minute video about the Dark Energy's arpeggiator functions below ).

The same functions should work on the A-190-3 ( and Dark Link ) too, but i haven't had any hands-on time with this module to check and haven't seen much info on the web.
It does look like a very basic arpeggiator that will be hard to program, only with external MIDI-controller-messages ( like the R2M if i am correct ), but it is a good start.
I would rather see a more dedicated arpeggiator module from Doepfer, with easy accessible buttons and switches for the different settings and run-modes. Something like the Toppobrillo Quantimator (PDF) or the forthcoming Flame Chord Machine would be nice...

The weird thing though is that the whole arpeggio function is not mentioned anywhere on the module's web-page while this is such a useful function.
In fact; it's the first A-100 module that has a (basic) arpeggiator (!)

Because an A-190-3 manual isn't available yet, you can find a bit more info on how the arpeggiator works in the Dark Link manual ( PDF /page 13)*

*thanks to Paul Rogalinski for the tip

Video: Using Doepfer Dark Energy Arpeggiator

Detailed reference video by Dmitry Shtatnov with Doepfer Dark Energy internal arpeggiator + live song performed using Dark Energy and A-100 modular system.

Saving Patches

One of the downsides of a modular synthesizer is the lack of memory banks.
There are times when you have finally found that perfect sound, but need some modules for other patches...
A good (photographic) memory will often do the job in the more simple cases for anyone, but for bigger patches you might need a little reminder sometimes.

To 'store' patches you have a few options;
First, always try to sample the sound you made with a (hard- or software) sampler. Although that often does not catch every aspect of your sound, it is always good to keep what you made in some audio-way. Try sampling it in all its varieties, with your favorite settings and or knob-twists.

Okay... you now have the sound , but not the list of modules that were used to make that sound.
Doepfer came up with the nice idea of patch-sheets in the last page of every module's manual.
You can print out these modules, stick them on a bigger sheet (i've even seen some on pinboards) and draw in your knob-settings and patchcables.
The idea is/was nice, but i hardly ever used these sheets. But it can be handy for some...

I also like the online Eurorack Modular Synth Planner. With hundreds of modules from 52 different manufacturers (!) you will be able to configure your patch including a variety of colored patch-cables and save it as a screenshot.
This great site is regularly updated with the latest eurorack modules, but still has a few (small) bugs and imperfections. Follow them on Twitter to get their latest updates.
Another online planner is Stefan Breitenfeld's Modular Planner, also very neat but with much less manufacturers/modules.

My personal favorite way to store my favorite patches is the modern way.
Thanks to my smartphone i always have a digital camera in my pocket.
One or two quick snapshots of my patches is often enough, and only takes a few seconds.

Most Wanted - Future Modules Update

It is always good to keep an eye on the posts from the Doepfer Yahoo Usergroup.
Not only to get answer to all the A-100 questions you have, the DIY-tips, and the interesting module discussions but also for Dieter Doepfer's own input, troubleshooting and the occasional company updates.
In one of his latest posts he announced a few interesting 'new' things on Doepfer's to-do list, including a few that are not yet on Doepfer's Future Module page.

The ones you can already find on that page are the A-190-5 polyphonic USB/Midi-to-CV/Gate interface, the A-142-4 Quad Decay, A-195-1 Pitch-to-CV/Midi/USB interface, A-192-2 CV/Gate to Midi interface, A-143-4 Quad VCO/VCLFO and the A-100 touch keyboard.

The original A-126(-1)

I already blogged about the forthcoming A-157 Trigger Sequencer (not much info on the Doepfer site, only in a NAMM 2010 brochure), but the update of the A-126 module was new for me.
The A-126-2 Frequency Shifter II will be a redesign of the old module. 

Because of availability of the special circuit CEM3382 used in the original module's internal quadrature VCO, the 'original' A-126 is no longer available and they had to stop the production of this module. 

It looks like Doepfer is now working hard on a succeeding model without an internal VCO.

Other modules that were mentioned were a VC Slope Generator ( no specs or further info available, but maybe something like the Serge Universal Slope Generator ?- i'm only guessing !), a Master Clock module/synced LFO, the A-100 bus board V2 with some Analoge Systems connectors ( no more Analogue Systems-to-Doepfer adaptors necessary? ), and an A-100 miniature power supply redesign 

Besides that, Dieter posted that they are also still working on various non-A-100 Doepfer products like the Dark Matter (Dark Energy expander with Noise, S&H, a second VCO, Multimode-VCF, additional waveforms and maybe some other effects), the Dark Link, and an expansion board for the DIY Synth. 

" ... still on our to-do list. But I can't say in which sequence the planned products will be released."

Note: Please don't call or mail them too often at Doepfer about release-dates or updates of future modules. The Doepfer website is updated very regularly, so you will find all the latest info there...

Controlling the A-100 via MIDI

In the beginning it was not difficult to pick a Doepfer MIDI-CV interface for your A-100 system.
The A-190 MIDI-CV/SYNC Interface was the only one available and there were not many other options.  (the A-191 MIDI-to-CV Interface / Shepard Generator was way more complex, i will discuss it in a future blogpost).
The A-190 is a powerful module that not only provides a few CV and Gate outputs, but also Portamento, Scale-settings, Pitch-bend, Glide, Clock and Reset signals, has a built-in (software) LFO and very flexible programmability.
Without a proper display it is quite awkward to program, but you'll quickly learn how to read the combinations of burning and flashing LEDs.
I do miss some further (software) development for this module. The arpeggio function, mentioned on the front-plate isn't even implemented (!)

A cheaper option that you can buy nowadays is the  A-190-2 Midi CV/Gate interface, which is based on the Doepfer MCV4. Only some minor changes were made for a better adaption to the A-100 system, e.g. five 3.5 mm sockets and zero-symmetrical CV for pitch bend, to be able to adjust the pitch bend range e.g. in combination with the precision CV adder A-185-2 and the glide function.
The module has no MIDI Thru and MIDI clock and reset functions though.

The new A-190-3 USB/MIDI-to-CV/Gate Interface that is in production stage has almost the same possibilities, but will be a modular version of Doepfer's upcoming Dark Link Module. This one will support USB and the release date for it is set for early 2011.
Another advantage of these two cheaper modules is that they don't need the additional +5V adapter. 

If you are looking for a polyphonic MIDI-CV contoller you will probably have to wait a while. Doepfer is busy working on the A-190-5, but it will be completely redesigned this year. A final version will  probably contain an LC display (similar to the A-187-1), some control buttons, a USB interface and higher resolution DACs with higher voltage range (probably 12 bit and 0...+10V). It will be a four voice polyphonic Midi to CV/Gate interface with 12 CV and 4 Gate outputs and different modes (e.g. unisono, four-fold monophonic, different four voice polyphonic modes.)

Tip: The monophonic MIDI-CV converters can write and read to the A-100 Busboard, more info on this HERE

Vactrol Basics

A Vactol is an opto-isolator device that is often used for channel-switching in many modern amplifiers, but these electronic parts can be used in various other ways too, for example in synth-modules like Doepfer's A-101 Series and the A-102 Low Pass Gate module.
There are many kinds of optical isolators, but the most common is the LED/photo-transistor type.

A vactrol is a combination of a light depending resistor (LDR) and light source (LED) both put into a small 100% light-proof case.

The principle of a Vactrol is very simple.
When an input current is applied to the LED, the output phototransistor turns on.
The only connection between the LED and phototransistor is through light -not electricity, thus the term optical isolator. 

These optical isolators are primarily digital in nature with fast response times suitable for interfacing with logic gates. Rise and fall times of a few microseconds, faster for some isolators, are typical.

So together, the coupled pair act as an electrically variable potentiometer.
Since the output element of the AOI is a resistor, the voltage applied to this output resistor may be DC and/or AC and the magnitude may be as low as zero or as high as the maximum voltage rating.
Because the input will control the magnitude of a complex waveform in a proportional manner, this type of isolator can be used as an analog control element in all kind of ways in analog synthesizers.

Find a review of my A-101-2 Vactol Low Pass Gate module  HERE

More info on Vactrols:   Doepfer Vactrol Basics page

                                      Vactrols on Wikipedia

                                      PDF via DatasheetCatalog.com

Arranging Modules

Like most of you all know i recently installed my 4th metal G6 frame.
It was about time that i did that, because i already had a few modules that didn't fit the old rack and that were lying loose in a drawer.
After installing the new frame i came up with the idea of this blogpost.

Of course i had to re-arrange my modules again... The old layout just didn't make any sense anymore. Some modules were so weirdly placed that patching them always resulted in a whole spaghetti of cables.
I couldn't find many guidelines for arranging modules on the web, so I just started and made a few notes during the process.

A few of my personal guidelines that work the best for me are:
-    Before you start, disconnect all racks from the power supply! Safety first!
-    Work from top to bottom. I'd almost say work from top left to bottom right. That will keep the system and the flow of signals much more 'readable'
( I'm not sure if this works for Arabic countries, where they read from right to left though... )
-    Try to keep all your multiples on the left side and the Mixers on the right side. I love distributing signals from the sides up and/or down first before i patch a new sound. This avoids cable-cluttering and keeps the overall look 'clean'.
-    Group the modules, eg: Sound Sources / Filters / VCA's / Mixers / Modifiers / Modulation sources / Switches and Sequencers / Clock/Gate/Digital Modules / Voltage Sources / Auxiliary and Special Modules
-    Keep modules that you often use in combination close to each-other ( see my PatchPierre BFF section )
-    Read the manuals of the modules regarding power consumption of each module, and make sure your busboard can handle all the modules that are connected in that row. - note that some require an additional +5V power supply with 50mA e.g. the low-cost 5V adapter - don't forget where you placed it.

-    Check the manuals again for other module-specific requirements. ( some modules should not be placed next to certain others, to avoid interference )
For example don't place oscillators next to a power supply and keep the distance between the Theremin modules at least 30 centimeters etc.
-    Working with colored cables and/or switches does help improving the readability of your system. Too bad Doepfer only sells a few colors in fixed lengths. Longer black and yellow plus shorter red and blue cables would be appreciated. Purple and orange cables too ( personally )
-    Don't forget to fill up the open spaces with blind-panels for safety and EMC reasons. ( ... i knew there was something missing in that first picture )

Okay... everyone has his own preferences on how to arrange their system, this was just a personal (short-) list of the things that i could think of at the moment.
Please leave some feedback if you have any suggestions. I might include more tips later.

Racks, Cases and Monsterbases

In the beginning it was easy; you only had a few choices:
You could either buy a 3-unit high rack (A-100G3), a 6-unit high rack (A-100G6) or the 6-unit high suitcase version (A-100P6) from Doepfer to mount and organize all your A-100 modules.
Nowadays you can choose from a huge variety of other housings from Doepfer, from 32HP width miniature-cases up to 168HP monster-cases.
You can even make your own cases/cabinets with the low-cost DIY-kits containing rails, a power supply and bus-boards.

The most economic versions nowadays are the low-cost plain wood cases (A-100LC6/LC9) ,which cost about 35% less than the metal and standard suitcase versions.
If that is not your thing you can always go for the monster-cases;
Twice the usable width of a 'normal' rack, but finished with a black or grey finish in a flightcase-look are available in many different shapes and sizes.
There's even a monster-base that fits under these cases, with 2 rows of 168HP width, one with horizontal alignment and a second with a 45 degrees inclined row.

- note from the Doepfer-site: " ...the 12U monster cases are a bit difficult to handle by one person only "

I recently ordered my 4th metal G6 case because i already owned three of them that are filled up to the max. I already have some loose modules lying around that i would love to have back in my system again.
Budget-wise i wanted to go for the LC9-version(s), but then i had to re-arrange the rest of my system too, to give it a same look. Too much work for now.

For my next expansion i am considering building myself a cabinet, using 5 or 6 A-100DIY1 kits . 

That is probably by far the most in-expensive way. If i sell my G6-cases second-hand, i will probably even have some money left to buy me an extra module or two. We'll see...

Blind Panels II

Beside for safety uses, as mentioned in one of my earlier posts, the blind-panels that Doepfer sells are also perfectly usable for all types of DIY-projects.
The 'standard' panels of 4,8,42 and 84 HP can be used for all types of original self-made modules or expanders. Sadly they don't have other sizes, but wouldn't it be nice if they had a 16HP and perhaps a 24HP to 'fill in the gaps'.

Drilling the metal plates is quite easy ( if you use the right tools ), and the panels come with pre-drilled mounting-holes.
If you don't like drilling, you can also order some pre-manufactured panels from the Doepfer A-100 specials list;


They still have many punched A-100 standard front panels of 4HP width, punched for 8 sockets, identical to A-180 front panel but without printing, very useful  for DIY or A-101-9 expansion  applications. You can save yourself some money by making your own A-180 multiple for almost half the price. (sockets can also be ordered at Doepfer )

Punched A-100 standard front panels of 8HP width are still available too. Punched for 5 potentiometers and 5 sockets (same as A-102, A-103, A-105, A-120, A-122, A-123, A-124, A-130, A-131, A-138), without silk screen printing.
They even  fit the Synovatron DIY1 and DIY2 kits. (*confirmed / ,but see feedback for remarks and more info)
Update March 3 2011: Synovatron now sells his own generic front panels for his DIY kits.

Doepfer also still has a few 14 HP front panels punched for 2 wheels and 4 sockets ( like A-174-2 ), without printing, that might useful e.g. for a DIY wheel module. Order it with two modulation wheels and you even get the front-plate for free...

CD-Tip III : Analogklang - Modulsystem A-100 Demo CD

This CD was published by Doepfer in 1995 to show off their then brand new A-100 modular system. It has 29 tracks and a large, colorful, fold-out booklet (in German) with a description of most of their early modules.

All the basic modules are demonstrated on this CD, that was produced by Andreas Merz from Weltklang and  narrated in German by a vocoded voice. The tracks are short, between 25 seconds and 3½ minute, what brings the total length of the CD to just 30 minutes.
This CD itself must be a collector's item by now i guess, because the item isn't available anymore on Doepfer's website. I'm quite sure i won't sell my copy... ever. This CD still means something special to me, and i did listen a lot to it, even before i bought my first modules.

Although the CD isn't available anymore, all tracks ( and some other sound-examples ) are still available for download HERE ( ...sadly enough in a poor ( 16Kbps) quality due to file-size decisions, but if you really need better audio-files you can contact Doepfer for better ones )
A must-have /or at least must-listen CD for all the real A-100 geeks and you might even get some new, fresh ideas out of it.

Blind Panels

The regular Doepfer 19-inch Euro-rack system has a usable width of 84 HP. If the modules you install don’t use up the entire 84 HP, you are advised to cover up the empty spaces with blanking panels due to safety and EMC reasons.

As i wrote in an earlier blogpost, the (static) electricity from the system causes the A-100 to be a real dust-magnet.
Blind Panels are available in the following sizes;

A-100B1  : 1   HP
A-100B2  : 2   HP
A-100B4  : 4   HP
A-100B8  : 8   HP
A-100B42: 42 HP
A-100B84: 84 HP

Doepfer also sells the A-100B1.5, a 1.5 HP wide blind panel that for example fits the  Analogue Solutions modules together with eurorack modules of other manufacturers. 

Volts per Octave

The Volts-per-Octave standard luckily turned out to be a quite good one.
A lot of (early) synthesizers manufacturers adapted this standard, 'invented' and popularized by Bob Moog.

Best known manufacturers of early products using the 1V/Oct standard are Roland, Moog, Sequential Circuits, Oberheim and ARP. The big benefit of standards like these is inter-compatibility between products of different manufacturers. It allowes them to communicate better.

The V/Oct standard was wider adapted as other standards, like for example Yamaha and Korg's Hertz-per-Volt standard, that  represented an octave of pitch by doubling the voltage. 
A few synths that use the Hz/V standard are:
Korg: 770, 900-PS Preset, M-500 Micro Preset, M-500SP Micro Preset, Mini Korg, MS-10, MS-20, MS-50, Synthe-Bass, X-911
Yamaha: CS5, CS10, CS15, CS15D, CS20M, CS30
Moog: Taurus I Bass Pedals
Paia: 2720, 4700 Series

The Hz/V standard was used before the log converter was used in VCO's and is essentially linear control as can be found on various signal generators and function generators like those used by the BBC Radiophonic Workshop before they got a VCS3*. There are/were solutions available that convert from  Hz/Volt to V/Oct and vice-versa.  ( like the Korg MS-02 ).

No wonder that the A-100 system uses the V/Oct. standard. You can easily synchronize your system with almost any (old) machine that you have lying around, and most MIDI-to-CV converters use the same standard too.

For example i love using the CV (and Gate) output of my Roland TB-303 to control my A-100 system. The signal arrives at my system via a  A-180 2x4 multiple, so i have 3 copies of both signals available at any time.
Sometimes i use the CV slightly detuned for an interesting effect, sometimes i put it through a voltage inverter first, something that doesn't work out with all your 303-lines because of tuning.

The Gate output (trigger) of the TB-303 can be sent through a delay for some more interesting echo-like effects.
There are so many possibilities for your other gear to communicate with your A-100 with the 1 V/Oct standard... just go ahead and try... and amaze yourself.

*thanks to Tony Steventon for additional info