A-138 Linear/Exponential Mixer

Module A-138 is a simple four channel mixer that can be used for either control voltages or audio signals. (although i hardly ever use one for CV)
Each of the four inputs has an attenuator, and a master attenuator, so that the mixer can be used to interface directly with an external mixer, amplifier, etc.

There are two versions of this module:
A-138 a: potentiometers with linear response, especially suitable for control voltage mixing.
A-138 b: potentiometers with logarithmic/exponential response, especially suitable for audio signal mixing.

The latest version from April 2004 is an improved version of the module A-138b.
For the revised versions control In1 works as a DC offset generator (about 0...+5V) provided that no patch cord is plugged into socket In1.
If this feature is not required it can be deactivated by removing a jumper on the pc board.
In the summer 2004 the A-138a was introduced with this improvement.

In the summer of 2007 Doepfer also released a mix expander module A-138x, that increased the number of inputs of the A-138 by five.
That module was discontinued last year...

Sample and Hold with Doepfer A148 by Raul Pena

Raul Pena from http://raulsworldofsynths.com/ just posted a few new video tutorials.
Here are the first six (of seven!) in a series dedicated to Sample and Hold,Track and Hold, and comparisons with the two.

Video 1 : Track and Hold Vs. Sample and Hold with Doepfer A148 S/H
http://www.youtube.com/watch?v=KvjiKzBaTAs

" Demonstration comparing Track and Hold with Sample and Hold using the Doepfer A148.Sound and Video by Raul Pena."

All other A-148 video's after the break

Most Wanted VI - Special Vocoder MIDI-interface

I read the following text on one of Doepfer's A-129 vocoder system pages a long time ago, but it is still on Doepfer's website;

" A special MIDI-interface for the vocoder system is planned.

The basic functions are a 16-way CV-to-MIDI interface and a 16-way MIDI-to-CV interface (way 16 will be used for other functions like controlling slew-rate or voiced/unvoiced).

The CV-to-MIDI section converts the CV outputs of vocoder analysis into MIDI controllers which may be recorded by a computer sequencer. 

The MIDI-to-CV section converts incoming MIDI controller information into CV's for the vocoder synthesis section. 

Additionally we plan to store some factory and user definable 'vocals' in the MIDI interface so that you may call up complete vocals (like 'a', 'e', 'o', 's', 'sh' and so on) by MIDI program change events (may be we use another MIDI event type for this purpose). 

Thus the vocoder system will become a universal MIDI controlled filter system not limited to the standard vocoder features. "

Okay, i must say that it all sounds impressive and also very useful.
I do hope this module will be taken into production, but i believe this has been
on Doepfer's webpage for a while now, which makes me think that this module will probably never be made.
It might be in the Universal 12 bit AD-processor-DA module plans, because these things do need some processing power but i'm not so sure about that...
With all the announced features you could imagine this would not be a cheap module to make, but we'll see though...

Find more of my 'Most Wanted' posts HERE

Wooden Ribbon Controller Project Part 2

My project is going great so far.
Most of the woodwork seems to be finished.
I carved out the whole  59.7 x  2.4 cm. strip where the fingerboard should come, about 3 mm deep across the whole surface.
I carved a bit too deep at places, but i will fill that up a bit with filler, so that should turn out fine.
The pressure sensor needs a flat surface, so that needs a little bit of extra attention.

I painted the wood 4 times now, with a glossy mahogany varnish, and it looks quite amazing IMHO...
It will get one last layer of varnish after the final assembly of the whole project
I screwed an iron ring at the top (but that might become an brassy one), and i am planning to screw one at the bottom for  attaching a shoulderband.

I changed my mind a bit about the old fingerboard that i wanted to use, but i will order a new pressure-board from Doepfer next week.
I also need to find a smaller piece of wood that can cover up the USB-connector or find another good way to hide the connections.

That does mean i have to wait a few weeks before i can take the last steps and finish the whole project.
I will keep you updated...

A-146 LFO2

Module A-146 (LFO 2) is a Low Frequency Oscillator, which produces periodic control voltages over a wide range of frequencies.
The LFO can be used as a modulation source for a series of modules (for example pulse width and/or frequency modulation of a VCO, modulation of a VCF cut-off frequency or amplitude modulation with a VCA).

It is quite different from the A-145 and A-147, that i discussed earlier HERE

Three outputs are available, with different waveforms: sawtooth / triangle; square wave, and positive-voltage square wave.
The waveforms are continuously adjustable from rising sawtooth, through triangle to falling sawtooth.
The same control affects the pulse width of the square wave.
A three-way switch can select one of three frequency ranges, spanning from one cycle every few minutes, at the lowest, up to audio frequency at the highest.

A nice LFO, but i don't own one myself... yet.
Too bad it has no CV input  and that it doesn't have a reset input...

More on waveforms: http://en.wikipedia.org/wiki/Waveform
also see Wikipedia for more indepth info on the different wave-forms:
Pulse wave             Sawtooth wave
Sine wave               Square wave
Triangle wave

Wooden Ribbon Controller Project Part 1

Today I decided to pick up an old idea that i had for a long time.
Whenever i play the Ribbon Controller, i tend to hold it like a guitar, not like most do on a tabletop surface.

I have always loved the combination of wooden elements and synthesizers.
This combination was/is still very popular since the early 1970's.
Look at all those (Mini)Moogs and many other synths with wooden side-panels for example...
That is why i also decided to make my Ribbon Controller out of wood.
It looks like a found a nice solution to an earlier project too.

So today i bought myself a nice piece of wood in the local woodshop.
On forehand i had the idea that the handle of an axe might be the kind of thing that i needed.
They had a few different sizes, but i found a hardwood unpainted axe hande that was 90 centimeters (3ft.) long and perfectly shaped and curved.
I might make it a bit shorter later, but for now this will do just fine.

I dismantled my old Ribbon Controler (i do own another one, the newer version) and drawn out the shape of it on the axe handle. I used 3 screws to fixate the fingerboard while doing that.
Next up is the carving... i want to sink the fingerboard into the handle, but that means i need to carve at least half a centimeter deep.

I already carved the first bit like the last picture shows, but i still have a long way to carve.
But i need to get myself a new chisel now so you will have to wait how this project will continue.
I will keep you updated... but don't expect this to be finished before 2012.

Ribbon Controller versions

Ribbon controllers, old model on top

One of the most used parts of my modular setup is without doubt my A-198 Ribbon controller.
You can read all i ever wrote about it so far HERE.
I love improvising with the manual controller and the sensitivity of the manual makes it fun to play with.

In combination with the A-156 Dual Quantizer and a A-170 Dual Slew Limiter it is quite easy to play, even for beginners.*
Together with and the different scales that are available on the A-156 you can make your ribbon-sliding-skills sound very impressive.
* I should note that is also easier to play the Theremin modules using these two modules.

From 2005 the A-198 (and R2M) manuals are equipped with an even more sensible pressure sensor.
The improved sensor now works along the entire manual.
So how can we distinguish these two models?
The newer version is white on top, instead of the greenish grey color of the old model's touch-surface.
The new version also does not have the text 'A-198' printed on it.

Ribbon controllers, new version at the bottom. Note; the orange stickers are not standard

The Doepfer R2M (Ribbon-to-Midi) is the stand-alone version of the A-198 with MIDI and CV/Gate outputs. R2M offers a lot more features than the A-198 (e.g. quantizing, gate function even in the hold mode, inverse scaling and many more)

Currently from June 2011 the cases have changed from silvergrey with black printing to black with white printing... also very slick...

Doepfer A118 Filtering with A120 VCF Low Pass Filter

More Video from Raul Pena (of http://raulsworldofsynths.com/)
This time almost 45 minutes long tutorials on using the A-118 Noise/ Random Voltage Generator in combination with the A-120 Moog Style Low Pass Filter... creating some interesting wind-effects...

Video 1 : Doepfer A118 Filtering with A120 VCF Low Pass Filter
http://www.youtube.com/watch?v=vin9o4GpJs8

" Part One Discussing the features of the Doepfer A188 Noise and Random Voltage Source module. Followed by a Demonstration of Filtering white and Colored Noise with the Doepfer A120 VCF Low Pass Filter. Sound and Video by Raul Pena. "

Video 2 : Doepfer A118 Filtering with A120 VCF Low Pass Filter Part Two
http://www.youtube.com/watch?v=9ZxRsxPLuI4

"Part Two Ongoing Demonstration of Filtering white and Colored Noise from the A118 Noise module with the Doepfer A120 VCF Low Pass Filter. Modulation Capabilities also explored with A147 VC LFO and A145 LFO. Sound and Video by Raul Pena."

Read more on the A-118 HERE
Read more on the A-120 HERE

Special Designs

Don't go calling or emailing Doepfer right away,
but if DIY-ing is not your thing you might find this next thing interesting:

" In principle Doepfer is able to make special designs, but most customers underestimate the time and consequently the costs for a special design.
Normally there are three steps for a custom design:

Development of the hardware (provided that none of their existing hardware products can be used), development of the software (provided that the design includes a microcontroller) and design of the mechanics (e.g. controls, housing, provided that the customers is not able to built his own case).

The hardware and software design is carried out at Doepfer, i.e. design of the schematics, PCB layout and software.
All mechanical parts of the design - i.e. PCB manufacturing, housing, treatement of the housing like drilling holes, milling slits, varnishing, printing and so on - is carried out by other companies specialized in such things.
Doepfer has no mechanical working place in their company.
The main problem for a special design is that all nonrecurring costs - i.e. design of schematics, pcb layout, programming the software, initial charges for the pcb manufacture, case/housing production and silk-screen printing - have to be payed by one customer only.

Even for a small design these nonrecurring costs reach the few thousands Euro range.
Normally these charges are divided by the number of devices that are manufactured (a few hundred or thousands as a rule).
Please keep in mind all these notes if you ask for a special design.
If you are willing to pay for all these steps of work they might make a quotation for you. "

from the Doepfer FAQ page

A-140 ADSR Envelope Generator

Perhaps i should have started my whole PatchPierre blog with writing about the most basic and essential A-100 modules first.

How the four parameters A, D, S and R
change the shape of an ADSR envelope

The A-140, Doepfer's envelope generator was released back in 1995/96, and was one the first modules available.

It is a simple ADSR (Attack, Decay, Sustain, Release) generator.

When this module is triggered it generates a variable voltage, changing in time, called an envelope.

The shape of the envelope is set by four variable parameters: Attack, Decay, Sustain and Release.
The envelope is started (triggered) by a gate signal either from the internal gate voltage on the system bus or, if a signal is put into it, from the gate input socket.

The varying voltage (visualized by an LED) is output in normal (positive) and inverted form, and can be used for all kinds of voltage controlled modulation of any VCO, VCF,  VCA or other CV controlled inputs.
The envelope can also be re-triggered, but that only works when the gate is opened.
The module  has a three-position toggle switch between three time ranges.
The envelope time can be set from about 50 microseconds up to several minutes.

Okay... There's not much extra to write about this elementary module, although i do like the inverted output (plus that it has two 'normal' outputs).
I should say that there are more economicly priced other envelope generators available.
My advice is to get yourself one of the Quad envelope generators for example... if your modular gets bigger you will probably need more EG's anyway.
I do have the four-fold A-143-2 Quad ADSR, but the A-143-1 Quad AD with only Attack and Decay, or perhaps the A-142-4 Quad Decay with just decay are just a few of the other options if you are looking for expanding your modular with basic EG's...