Doepfer - CTM64
CTM64 is an universal MIDI Out kit. Up to 64 free contacts can be connected to generate MIDI note on/off or program change messages.
CTM is suitable to retrofit keyboards, switch panels, button arrangements or any other contacts so that they are able to transmit MIDI data. Up to 4 potentiometers can be connected to generate common MIDI controllers and pitch bend. Additionally a 1/4 jack socket is available for connecting a sustain pedal.
Two different modes are selected with the first of 8 jumpers: note on/off or program change. In the note mode closing of a contact generates the corresponding MIDI note on message, opening generates note off - both without velocity (velocity is fixed to 100). In the program change mode closing of a contact leads to the corresponding MIDI program change message. additional mode: control change (transmission of Midi control change messages instead of Midi note on/ff) additional mode: toggle operation (alternating transmission of note on and note off whenever the contact is closed, useful for toggle switches e.g. for Ableton Live)
The note offset (i.e. the MIDI note number assigned to the first contact) can be set to 0 or 36 with the second jumper. With two more jumpers one can transpose up/down one octave, i.e. +12/-12 semitones. Instead of these jumpers a 3-position switch (1-0-1) working as an octave switch can be soldered to the corresponding pins of the jumper pin header. In this way the note offsets 0, 12, 24, 36 and 48 are available. If another note offset (e.g. 41) is required the contacts are displaced correspondingly and the unused contact terminals are left free.
In the program change mode the offset can be set to 1 or 64, i.e. setting the program number range to 1-64 or 65-128 (0-63 or 64-127 in MIDI code). With two daisy-chained CTM64 the whole program number range 1...128 is covered.
The 4 potentiometer plugs are used to connect up to 4 potentiometers (e.g. rotary, slider, wheels or others) generating the MIDI messages pitch-bend, modulation (controller #1), volume (controller #7) and monophonic after touch.
The 1/4“ jack socket can be used to insert a sustain pedal (contact type ”closed at rest” is required) generating the MIDI sustain message (controller #64).
The MIDI channel for all messages transmitted by the CTM64 is set with the last 4 jumpers.
The 64 contacts are connected to four double row pin headers with 16 pins each. 16 pin socket-connectors with flat cable can be connected to these pin headers (not included with the CTM64). Additionally there is one common pin for all contacts. Pay attention that only free contacts can be used. This means that the contacts are not allowed to be connected with another electronics or connected with a fixed voltage (e.g. GND). The maximal cable length between CTM64 and the contacts is about 50 cm/2 ft. Beyond these length the correct operation is not guaranteed. It depends upon the cable specifications (capacity/inductivity of the cable) and the environment (emc interferences) if longer distances are possible. For distances beyond 50cm/2ft one has to try out if it works. For long distances between CTM64 and the contacts the CTM relay board is recommended.
For the potentiometer four male pcb connectors with 3 pins (GND, slider, +5V) are available. Suitable female connectors with assembled cables can be connected to these pin headers (not included with the CTM64).
CTM64 is equipped with MIDI In and MIDI Out. The incoming MIDI messages are merged to the data generated by the CTM64. In this way several CTM64 can be linked together (e.g. 3 CTM64 required for 2 keyboards with 61 keys and one basepedal with 32 keys, or switch boards with more than 64 switches).
CTM64 is available only as an assembled and tested pc board. The pc board measures are about 105 mm (length) x 90 mm (width) x 30 mm (height). Four 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. The configuration of CTM64 (i.e. MIDI channel, mode, note offset and so on) is made by the customer with 8 jumpers - as described above.
We do not offer a suitable housing as the CTM64 is normally installed into the housing of the keyboard or switch board.
An external power supply (7-12VDC@min. 250mA) is used and not included.
Electronic basic knowledge is required to install the CTM64 board. If you are not sure if your knowledge is sufficient please consult an expert.
A connector set suitable for CTM64 is available at extra charges. This set includes four 16 pin flat cables with 16 pin socket connectors pressed to the cables at one end (length about 50cm) and four 3 pin female connectors with assembled cables for the potentiometers (length about 30cm, potentiometers are not included).