Doepfer A110 Filtering Demo's with A-101-2 and A-120 by Raul Pena

Raul Pena ( from http://raulsworldofsynths.com/ ) made another excellent set of tutorial videos.
This time it is all about filtering; In a few episodes he explores all functions of the A-101-2 Vactrol Low Pass Gate filter, in comparison with the A-120 Low Pass Moog-style filter.
Very interesting stuff again...

Video 1: Doepfer A110 Filtering with A101-2 and A120 Intro
http://www.youtube.com/watch?v=QmrB9EOVgb8
" Short Introduction into Filtering the Doepfer A110 Standard VCO. Dicusses Features and Functions of the Doepfer A101-2 Low Pass Gate and A120 VCF Low Pass Filter.Sound and Video by Raul Pena. "



Video 2: Doepfer A110 Filtering with A101-2 Low Pass Gate
http://www.youtube.com/watch?v=qBt7wozgjjg
" Demonstration of the Filtering of the Doepfer A110 VCO with an A101-2 Low Pass Gate. Next More Filtering with the A101-2 Low Pass Gate."

More video after the break -

Hardcore Modding the A-182-1 Switched Multiples

I must admit i am not a very sophisticated modifier / solderer.

I don't have an electronic background, find it hard to concentrate at times, and i can easily lose my patience when i'm working on stuff.

I am quickly satisfied with the modifications that i do, as long as my projects look good on the outside and are safe (i.e. no loose wires inside that can cause short-circuiting etc.)

A good example of my somewhat rude approach is my A-182-1 Switched Multiples modification.

Originally this module is a simple passive multi-connector similar to the A-180 Multiples module.

In the A-182-1 each socket is equipped with a 3-position switch that allows to connect the corresponding socket to the internal bus #1 (left position), bus #2 (right position) or to turn the socket off (center position).

A-182-1 Modification detail

I wisely decided to split up the A-182-1 into a 2 x 4 Multiplier, like i did with my A-180 because I found this this modification very handy.

I can now use my modified A-182-1 Switched Multiple for quick switching between my keyboard ( via MIDI ) and my A-198 Ribbon Controller.
For this i split up the Multiple in two halves, the upper half controls the Gate, the lower half controls the pitch ( CV )

More info on this HERE

Okay... I know i could have scraped of some of the wires on the PCB to do this modification, but i wasn't completely sure if that would be enough. To be sure that there were no other connections i just took a junior hacksaw and cut the whole PCB in half. 

As this is a passive module (not connected to the busboard) i thought my mod could hardly go wrong with this.

It might be a bit rude perhaps, but it works!

SiteTip VI : MIT Open Courseware Music and Technology: Algorithmic and Generative Music

It's kinda weird that, if you search well, there are 2 Music and Technology Courses on the site of the Massachusetts Institute of Technology (MIT) with the same course number (21M.380).

I blogged about one earlier (Contemporary History and Aesthetics, find the blogpost with an interesting 80-minute video HERE) and i am still very enthusiastic about it, but the other one is also very informative.

This course, Algorithmic and Generative Music, as taught in spring 2010 by Christopher Ariza examined " ...the history, techniques, and aesthetics of mechanical and computer-aided approaches to algorithmic music composition and generative music systems. Through creative hands-on projects, readings, listening assignments, and lectures, students will explore a variety of historical and contemporary approaches. "

Surfing through the pages of this course you will find a lot of interesting information on (analog) sound, music history and much more, again accompanied by many links to other interesting reads and audio-examples.

Find the course homepage HERE
Download the lecture notes HERE ( 11.8 Mb PDF )
Full course Materials can be downloaded from HERE

Licence info:
Ariza, Christopher. 21M.380 Music and Technology: Algorithmic and Generative Music, Spring 2010. (Massachusetts Institute of Technology: MIT OpenCourseWare), http://ocw.mit.edu (Accessed 16 Oct, 2011). License: Creative Commons BY-NC-SA

A-157 Trigger Sequencer Update

Here's an update on the long-awaited A-157 (or whatever the module-number will be) Trigger Sequencer module.
I wrote about this highly interesting module earlier, you can find that post HERE

This is what Dieter Doepfer's feedback was, when this step-sequencer got mentioned this week in the Doepfer A-100 Usergroup :

A-157 Prototype(s) , as shown at NAMM 2010

"...it will definitely come !
At present we are waiting for the new PCB prototype with 16 x 8 buttons and LEDs.
Our first plan to use two pc board with 8x8 buttons and LEDs did not work because this would cause a gap between the steps 8 and 9 because of the space required for the PCB connectors.

Our plan is to separate the 16x8 button/LED board from the control unit as it seems that there are two groups of users: those who vote for a simple, easy to use (and soon available) version and those for a "sophisticated" version with additional features (probably with LC display to handle all functions).
The plan for the simple version is to have only two clock/start/stop inputs available (clock #1 for the units 1-4, clock #2 for 5-8) and a simple memory management (similar to the TR808).

For the "sophisticated" version there are plans like independend first/last step for each row, copy and paste functions between rows and memories, right/left shift of complete rows, longer patterns (A, AB, ABCD), maybe intros, fill in's, track programming, more than two clocks and some more.

To handle these additional functions probably an LC display and additional buttons will be necessary.
But this information is very preliminary.
One could use the standard control unit at first and then replace it by the high end version as soon as it is available. "

Quick Tip VIII : Mounting the A-174-2 Wheels Module

Please be aware of this when you want to install an A-174-2 Wheels Module in your A-100 rack;

A-174-2 Wheels Module, note the pot on the left

As the potentiometer of the left wheel projects about 10 milimeters beside the rim of the front panel, a 2 or 4 HP blind panel has to be mounted left from the module. "

A-174-2 Sideview

Unless the module left to the A-174-2 has sufficient space in this area of course.Like an A-174-1 Joystick Controlled CV, for example.

None of the A-100 modules that are 4 HP wide fit there...

Installing the A-100NT5 +5Volts Adapter (old type)

Some of the A-100 modules, for instance the A-113 Subharmonic Generator and MIDI-modules A-190 or A-191, need an extra 5 Volts power supply.

The old way was by doing this with the A-100NT5 5 V supply, but because installing it was 'suitable for qualified personnel only because of electrical safety' Doepfer doesn't sell these adapter anymore.

The 5V power supply needs to be mounted near to the main power input, on the blank upper back panel with four stand-offs, nuts, serrated washers, and bolts. 

Newer back panels (since summer 1999) are already equipped with the 4 mounting holes required for the 5V supply.

If you are considering installing and connecting the A-100NT5, it’s crucial to take note of the following safety instructions:

• The installation and connection of the A-100NT5 must only be carried out by a qualified electrician or technician.
• If no suitable expert is available, the rack must be sent to a service centre or direct to Doepfer Musikelektronik
for the power supply to be fitted.

• Danger! Before installation and connection of the power supply, it is essential that the whole rack is isolated completely from the mains current.


Note: The new A-100 AD5 5 V adapter module can simply be plugged into a free socket on the bus board; The current is taken from the 12V supply! 

Find info on both adapter(s) HERE

Find the full installation instuctions of this adapter in THIS PDF

Filters V : A-120 24 dB/Oct Low Pass Moog Style Filter VCF1

Perhaps the best known low-pass filter in analogue synthesis was developed by Dr Robert (Bob) Moog in the late sixties.

It was used in the modular Moog synthesisers of that decade, but it got really popular in 1970 with the introduction of the Minimoog.

Moog's 4-pole filter is built with a co-called "transistor ladder" design with a cut-off slope of -24 dB/octave. That’s what gives it its classic, legendary Moog sound.
 Resonance is adjustable all the way up to self-oscillation - in which case the filter behaves like a sine wave oscillator.

The Doepfer A-120 is a very nice Moog emulator, but still most reviews say it doesn't sound 'Moogy' enough.
( i sadly don't have a real Moog to compare and verify that )
Moog's original circuit was flawed because it exhibited a small amount of distortion. Many engineers would have tried to correct this but Moog didn't.
He probably found that the sound was musically pleasing and he was probably right...
Maybe this module just sounds a bit 'too clean'.
It does still have a warm character, and it sounds very impressive in my opinion.
( and definitely unlike any of my other filters ).

Whenever i hear the name Moog i mainly think of great (Minimoog) synth-lead solo's or hand-played fat basslines, but you can also use this filter for wobbly dub-step basslines, sequenced loops and other (housey) basslines.

An interesting and more in-depth study on the Analysis of the Moog Transistor Ladder and Derivative Filters can be found in this PDF by dr. Timothy E. Stinchcombe.

Video : Doepfer A-120 (Moog) Low Pass Filter Demo by NetPierre

" Doepfer A-120 (Moog) Low Pass Filter Demo by NetPierre
created for my blog at http://PatchPierre.blogspot.com
A simple sawtooth wave from my A-110 into Audio in.
An envelope generator signal is sent into CV2, and some noise from the A-118 is fed into CV3.
Drums are provided by an Elektron Machinedrum "