Sujet Midi avec doepfer mc v1

Hors sujet : MONOPHONIC MIDI-TO-CV-Interface MCV1

(Version 4.0)


USER'S GUIDE

MCV1 is a monophonic MIDI-to-CV/GATE-Interface to control vintage analog synthesizers equipped with CV and Gate/Trigger inputs via MIDI. MCV1 is suitable for synthesizers using voltage control characteristics of V/Octave or Hz/V and gate voltages from +5V to +12V or switched trigger (S-Trig). MCV1 is eqipped with one CV (control voltage) output to control the VCO's (Voltage Controlled Oscillator) and one Gate/Trigger output to control the Envelope Generators (e.g. of ADSR type). If you want to control more than one syntesizer module or if you need more than one control voltage (e.g. for dynamic/velocity, VCF frequency or resonance, VCA, Envelope amount, LFO frequency ....) you need the MCV8 which is equipped with 8 CV and Gate outputs.


1. CONNECTIONS (Rear Panel)

The MCV1 does not have a built-in power supply. Instead it uses a plug-in type EXTERNAL POWER SUPPLY (AC adapter). The power supply is NOT included with the MCV1 and must be purchased locally by the user.
We recommend the DOEPFER PS1 AC adapter (VDE approved) but MCV1 will work with every AC adapter beeing in accordance with the following specifications. The adapter must be able to deliver 7-12 V DC unstabilized voltage, as well as a minimum current of 300 mA. The POLARITY of the low voltage plug connected to the MCV1 must be pin = +7...12V and ring = GND. If the polarity is incorrect, MCV1 will not function. However, there is no danger of damage to the circuitry since it is protected by a diode. If the MCV1 is used in Germany the external power supply should be VDE approved.
The MCV1 is turned on by plugging the AC adapter into a wall outlet and connecting it to the appropriate jack on the back of the MCV1. There is no separate ON/OFF switch.

Connect MIDI IN of the MCV1 to MIDI OUT of the MIDI transmitter (MIDI masterkeyboard, synthesizer, sequencer ....). The MIDI THRU of the MCV1 may be connected to the MIDI IN of other MIDI devices (optional).

The CV and GATE Outputs of the MCV1 are connected to the CV and Gate/Trigger input of the synthesizer module to be controlled by the MCV1.

The factory setting and adjustment of the CV output is 1.00V/Octave. To change or re-adjust the scale you have to insert a small screw driver into the the hole labeled ADJUST right of the CV jack and turn the potentiometer setting to the desired value. The characteristics of the CV output may be set to V/Octave or Hz/V (see chapter 2). The voltage range of the CV output is 0...+5V, i.e. 5 octaves in the V/Oct. mode.

The factory setting for the GATE output is +5V voltage gate. If you want to change the setting you have to remove the cover plate. Before opening the case disconnect the MCV1 from the AC adapter. On the pc board inside you may find a JUMPER behind the CV jack. The jumper can be set in one of 3 ways: +5V or +U voltage gate or SWITCH TRIGGER (S-TRIG. e.g. used by MOOG).
The gate types +5 and +U are labeled on the pc board. To select S-trigger you have to remove the jumper. There are 4 pins labeled "JUMPERS" at the edge of the pc board to take up unused jumpers. +U means that the gate voltage is equal to the output voltage of the AC adapter used. As the admitted voltage range of the AC adapter is +7...+12V the gate voltage has the same range when the jumper is set to +U. E.g. if your synthesizer requires a gate voltage of +10 V or more you should use the +U setting of the jumper and an AC adapter with about 12V output voltage.
Which type of CV characteristics and Gate is required for your synthesizer you may find in the manual of your synthesizer.


2. OPERATION

The MCV1 is SWITCHED ON by plugging the AC adapter to the jack on the back of the MCV1. There is no separate ON/OFF switch. After power on the LED on the front panel flashes 4 times indicating software V4.0. In the normal mode (i.e. not in the learn mode) the LED displays the state of the Gate output.

When turning on the MCV1 the last configuration before the unit was turned off is called up, i.e. the parameters for MIDI channel, reference note, gate polarity, CV characteristic and retrigger.

Pressing the button on the frontpanel calls up the LEARN MODE. The learn mode is indicated by the flashing LED. In this mode the MCV1 is looking forward to an incoming MIDI note on or program change event.

In case of an incoming note event in the learn mode the note number and the channel of the event are taken over as the new REFERENCE NOTE and MIDI CHANNEL of the MCV1. The reference note is the MIDI note number that belongs to 0V CV output. In practice you simply enter the learn mode and press the key on your MIDI keyboard that should belong to 0V CV. MIDI note events below the reference note or more than 5 octaves above the reference note are ignored as the CV voltage range of the MCV1 is 0...+5V. The factory default settings of reference note and MIDI channel are 36 (C) and 1.

In case of an incoming program change event in the learn mode the following program change numbers are relevant.

PRG CHANGE # FUNCTION REMARK

1 Normal gate/trigger (non inverting) 1
2 Inverting gate/trigger 1

3 V/Octave CV characteristics 2
4 Hz/V CV characteristics 2

5 Retrigger off 3
6 Retrigger on 3

GATE/TRIGGER POLARITY / Remark (1)

If voltage gate is selected with the jumper you may switch between normal gate (i.e. +5V/+U if key is pressed and 0V if key is released) and inverted gate (i.e. 0V if key is pressed and +5V/+U if key is released). In case of S-Trigger (jumper removed) the circumstances are reverse. If the behaviour of your synthesizer is opposite as desired (i.e. the sound appears if the key is released on your MIDI keyboard) you have to change this parameter with program change #1 or #2 in the learn mode. The factory default setting is normal gate.

CV CHARACTERISTICS / Remark (2)

With program change #3 and #4 in learn mode you may select between V/Octave and Hz/V characteristics for the CV output.
V/Octave is used by most of the synthesizer manufacturers (Moog, ARP, Oberheim, Roland, Sequential Curcuits, EMS, Doepfer). When V/Octave is chosen incoming MIDI pitch bend events affect the CV voltage. The maximum pitch bend voltage travel is +/-1 V corresponding to +/-1 octave. You have to pay a little attention when using the pitch bend function. If you play a note on your keyboard which corresponds to a CV voltage below +1 V or above +4 V not the entire pitch travel is available as the possible output voltage ranges only from 0 to +5V. If you want to use the pitch bend function you should play in the mid range to have enough voltage travel for the pitch bend function.
As far as we know Hz/V is used only by some Korg or Yamaha synthesizers. If Hz/V is selected incoming MIDI pitch bend events do not affect the CV output. Because of the non linear behaviour of the Hz/V curve the resolution is very poor in the lower voltage range compared to the V/Octave mode. So the Hz/V mode should be selected only if there is no other solution. The Korg Synthesizers MS10 and MS20 e.g. are equipped with an external control input labeled "TOTAL" that can be adjusted to 1V/Octave with the control knob labeled "MG/T.EXT.". Using this input we obtained much better results than with the Hz/V control inputs.
The factory default setting is V/Octave.

RETRIGGER / Remark (3)

With this parameter you may select whether a new gate/trigger pulse is generated when playing LEGATO (i.e. playing a new note on the keyboard while the key of the former note is still pressed). The factory default setting is retrigger off.
Additionally the MIDI controllers LEGATO (controller #68) and SUSTAIN (controller #64) affect the gate output in the usual manner.

Additional comments

Whenever the MCV1 receives a MIDI note on event on the actual MIDI channel and in the range between the reference note and 5 octaves above it calculates the corresponding CV voltage and activates the gate output. When the matching note off event appears the gate is deactivatet but the CV output holds its value. MCV1 is working with HIGH NOTE PRIORITY i.e. if more than one key is pressed on the MIDI keyboard MCV1 takes its information from the highest key pressed. This is the behaviour of the most monophonic analog synthesizers (e.g. Mini Moog).