DOEPFER Dark link Instrukcja obsługi - Strona 16
Przeglądaj online lub pobierz pdf Instrukcja obsługi dla Sprzęt nagrywający DOEPFER Dark link. DOEPFER Dark link 20 stron. Usb/midi-to-cv/gate interface
Również dla DOEPFER Dark link: Instrukcja obsługi (20 strony)
Drukuj stronęNuts'n bolts of MIDI-CV/Gate conversion
Dark link
DOEPFER
4. Nuts and bolts of MIDI to CV/Gate conversion
As you may surely know, synthesizers from the early days of electronic music (70ies and early 80ies)
where using a so called analogue sound generation. Oscillators, filters and amplifiers generated sounds,
while their parameters pitch, timbre and volume where controlled by voltages. The voltage that is control-
ling pitch is usually provided by the instrument's keyboard: The higher the key, the higher the control-
voltage, the higher the note, generated by the oscillator.
The loudness contour of an analogue synthesizer is generated by an envelope generator. This has to be
started by a certain signal, the "gate" or "trigger" which is also provided by the keyboard. In short: To make
an analogue synthesizer producing a sound (in the most simple case) a suitable controlvoltage to deter-
mine the pitch and a gate signal to start the tone is needed.
When MIDI came up, controlling a synthesizer totally changed. MIDI transports information of pitch,
loudness, note- on and -off and some more information as digital data.
To connect both worlds – meaning to integrate a classic analogue synthesizer into a modern MIDI based
setup – we need a converter, that translates the digital data into analogue voltages. This is exactly what
Dark Link is doing.
In the early days of synthesizers, not all specifications where subject of technical standards. Some
manufacturers choosed their own ways of design. Due to this, some of the most sought after vintage
synthesizers have different specifications concerning voltage control of pitch and start of their envelope
generators. This should be kept in mind, when using them in connection with a MIDI to CV/Gate interface.
Voltage control of pitch / scaling
With most analogue synthesizers, 1volt increase of pitch contolvoltage means 1 octave increase of the
pitch. This so called octave/volt scaling has become a common standard and still is for modern analogue
synthesizers. Also Doepfers A-100 modular system and the Doepfer compact synthesizer Dark Link use
this standard. So also Dark Link makes use of it for good reason. Only a few vintage synthesizers (e.g.
Korg's MS-modells and Yamaha CS-modells) make use of different scaling-types and thus cannot be
played tonally in connection with Dark Link.
On most analogue synthesizers, the input socket for external pitch control is labelled "KBD in", "VCO CV
in", KEY Volt in", "Oscillator-CV in" or quite similar. Connect Dark Links CV1 to this input.
Gate
To start the envelope generators, there are also different standards in use for specific synthesizers. the
common standard is a positive gate-signal, meaning a positive voltage when a key is held down and 0 volt
when no key is pressed. Nearly all of the classic synthesizers make use of this system, e.g. Roland, ARP,
Oberheim. If your synthesizer might be one of the few units that works the other way round (a positive
voltage when no key is pressed and 0V when a key is pressed), Dark Link can be configured like this (see
page 12, note (4).
Some vintage Moog synthesizers (e.g. Minimoog, Prodigy) use a so called "switch trigger" or "s-trigger". In
such a case, please make use of Doepfers switch trigger cable, available at your local dealer (hopefully) .
This cable transforms a gate signal into a switch trigger. Please note that the use of this cable reverses the
behaviour of the trigger polarity. If your synthesizer might behave strange resp. in a reversed way (envelo-
pes are started when key is released instead of being pressed) please simply change the trigger polarity.
16