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The Doepfer Modulation Wheel Kit

Contains a special rotary potentiometer (10k linear) with nut and washer, a modulation wheel made of black plastic, a mouting bracket, rubber buffer (for a soft touch of the wheel against the angle) and a fetch-back spring that can be used (e.g. for pitch bend) or not (e.g. for modulation or volume control).

Supplied as a kit for assembly by the user.


Overall: ~67mm x 33mm x 63 mm (mounting angle, wheel and potentiometer), ~53mm x 20mm x 40 mm (without wheel and potentiometer)
Diameter of the wheel: ~ 67 mm
Width of the wheel: ~ 10 mm
Distance of the mounting holes of the mounting bracket: ~ 32 mm

Technical remarks: 

Please note that only ~40% of the full rotating angle of the potentiometer is covered. If the end terminals of the potentiometer are e.g. connected to GND and +5V, a voltange range 0...+1.6V would be covered! 

Construction notes for the modulation wheel kit: Modulation_Wheel_kit.pdf

The Doepfer Wheel Electronics

Wheel Electronic (abbreviation: "WE" in the following) is a universal electronics DIY MIDI kit designed to connect modulation or pitch wheels. But it can be used also for joy sticks, single or multiple foot controllers (analog or on/off), breath controllers or even normal potentiometers. In addition a connector for a sustain foot switch is available.

Up to 4 continuously variable "analog" elements and a "digital" switching element (e.g. a sustain foot switch) can be connected.

Application examples:

  • pitch bender
  • wheels
  • joy sticks
  • breath controllers (e.g. Yamaha BC-1/2/3, additional resistor required, please refer to the user's manual)
  • foot controllers (continuos)
  • foot switches (on/off), momentary or toggle
  • rotary potentiometers
  • slider/fader potentiometers

Different elements can be combined simultaneously. Here are some examples:

  • pitch bender, modulation wheel, volume control (rotary or slider potentiometer), breath controller and sustain foot switch
  • pitch bender, three modulation wheels (e.g. modulation, volume, after touch) and sustain foot switch
  • pitch bender, two modulation wheels (e.g. modulation and after touch), one rotary or slider potentiometer (volume) and sustain foot switch
  • pitch bender, modulation wheel and joy stick
  • two joy sticks
  • four foot controllers for volume control of four Midi channels
  • dual or tripe foot controller (on/off or analog) and rotary or slider potentiometer
  • two modulation wheels or switches to control the rotary speakers of the organ software B4 (von Native Instruments), two rotary or slider potentiometers for volume and expression

The four "analog" elements are connected to pinheaders with 3 pins. For the "digital" switching element a pinheader with 2 pins is available. The pin headers are the white parts in the above picture.

Four 3-pin cable sets and one 2-pin cable set about 30cm each with suitable female connectors are included (please refer to the pictures of the applications examples below).

Four jumpers are used to select the Midi channel. 

Another four jumpers are used to select one of these assignments of MIDI control change numbers, pitch bend or after touch to the five connectors:









































ST1...4 are the connectors for the continuously variable elements. ST5 is the connector for the switching element.

For details about the abbreviations and specifications please refer to the user's manual.

WE has some special features compared to other Midi control electronics (e.g. Pocket Electronic):

  • The upper voltage that is assigned to the Midi data value 127 can be adjusted exactly with a multi-gang trimming potentiometer. This measure is necessary e.g. for modulation or pitch wheels, foot controllers or joy sticks that do not cover the complete angle of rotation. If such an element is connected to GND and +5V the maximal output voltage is much less than +5V (e.g. +3V only). Even breath controllers (e.g. Yamaha BC-1/2/3) output only about +3.5V maximal control voltage. If an electronics is used that analyses the full voltage range 0...+5V the higher Midi data values are missing.
  • The voltage range can be reduced with the trimming potentiometer to 0...+3V.
  • For each of the four elements a jumper is used to select if the full voltage range (0...+5V) or the adjustable voltage range is used for measurement. This is necessary if different elements are used simultaneously (e.g. modulation wheels or foot controller with reduced voltage range and normal rotary or slider potentiometers with full voltage range).
  • If an element is assigned to Midi pitch bend a "plateau" is used in the middle of the voltage/data range (data value 64). This feature is meaningful in combination with spring-loaded wheels or joy sticks as due to mechanical tolerances the exact center position is not always reached.

The MIDI data range is 0...127 with 7 bit resolution.

The sampling rate is about 50-60 samples/second (according to incoming Midi data that have to be merged to the data generated by WE; the maximum rate is obtained without incoming Midi data).

Even voltages sources can be used instead of the controlling elements.

An example for this application are the Yamaha breath controllers BC-1/2/3.  In this case the voltages applied to WE have to be strictly within the range 0...+5V (referenced to WE GND) !

Voltages beyond this range will destroy the WE !

WE is equipped with MIDI In and MIDI Out. The incoming MIDI messages are merged to the data generated by WE- provided that the incoming MIDI data range is not too big.

In this way several WE can be linked together or combined with other electronics like the CTM64, MKE, Pocket Electronic and Dial Electronic

An LED is used to indicate the Midi activity.

WE is supplied as an assembled and tested pc board.

The pc board measures are about 60 mm (length) x 55 mm (width) x 30 mm (height).

Several mounting holes with 3 mm diameter are available for mounting the pc board to a suitable base e.g. with distance sleeves or spacers and screws.

An external 7...15V/100mA DC adapter for power supply is needed.

DC connector with 5.5 mm outer diameter and 2.1 mm inner diameter, polarity: plus = center, minus = ring



















The Doepfer MKE Universal Keyboard Electronics Module for 4/5 Octaves


The MKE is a Universal Keyboard Electronics Module to build custom-made MIDI controllers that include a keyboard.

These units can be connected to MKE:

  • Standard keyboard manufactured by FATAR/Italy with 2, 3, 4 or 5 octaves (e.g. the keyboard types TP6, TP60...64, TP/7, TP/8 or TP/9, diode matrix type "DF")

  • Pitch bend wheel (special spring-loaded rotary potentiometer)

  • Single Modulation wheel (special rotary potentiometer)

  • Rotary or fader potentiometer for loudness/volume control (MIDI CC#7)

  • After touch sensor or socket for sustain switch or another potentiometer for any MIDI controller

The MKE pc board has these controls available:

  • 6 black rectangle momentary buttons (about 12 x 22 mm) with integrated LEDs

  • 3-digit LED display (about 19 x 38 mm)

The 6 buttons are used to control these parameters:

  • MIDI channel 1...16

  • Transpose (lowest note in octave intervals, 0-12-24-36-48-60)

  • Program change 0...127

  • Controller number 0...127 resp. After touch

  • Up (increment of the value shown in the display)

  • Down (decrement of the value shown in the display)

In addition one can select between dynamic and non-dynamic operation. In the non-dynamic mode the (fixed) velocity value can be adjusted. The velocity implementation in the dynamic mode has been optimized for the Fatar keybed 61TP/9. When other keybeds are used the dynamic behaviour may be not optimal. It's not possible to change the dynamic behaviour for other keybeds.

MKE has a non-volatile memory for the parameters MIDI channel, transpose, program number, controller number and dynamic/non-dynamic mode. After the next power on the previous values are called up. 

MKE is equipped with MIDI In and MIDI Out. The data appearing at the MIDI in are merged to the data generated by the MKE. Consequently several MKE can be daisy-chained or combined with other OEM controllers to build a custom-made MIDI controller.

MKE is available only as an assembled and tested pc board. The pc board measures are about 71 mm (length) x 85 (width) x 45 mm (height). Four mounting holes with 3 mm diameter are available for mounting the pc board to a suitable base or front panel e.g. with distance sleeves or spacers and screws.

An external power supply (7-15VDC@min. 100 mA) is needed. The pc board is equipped with a standard low voltage connector ( 5.5 mm outer diameter and 2.1 mm inner diameter, polarity: plus = center, minus = ring).


Email:  elby-designs@bigpond.com
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