Hello ...
>>>
----- Original Message -----
Sent: Monday, October 31, 2005 2:32
PM
Subject: [vintagesynthrepair] Arp Odyssey
CV/GATE
>Hey All.
>Here I am again. As I said on previous posts,
I just bought this Arp Odyssey Whiteface. It
>has a CV/GATE build in as
well, but I cannot get it to work. I have the Roland MPU-101
>interface
(that I already use for my SH-101 - which is working like a charm).
Yes it does, I use it for my Minimoog...
>The Arp has
these specs CV in+out, Gate in+out, Trigger in+out.
>My SH-101 do
not have the "Trigger" option.
>;And the MPU-101 does not have a "triggerout" -
The MPU-101 has a trigger out but it´s called "GATE" !!!!
>What does this do? Is it necessary to get it
working?
It is necessary !
The CV-out of the MPU-101 carries the "PITCH"
( p.ex. what key you have pressed in which octave range ) and the
"trigger" or "gate" -out carries a "pulse"-wave which opens/closes the synths
VCA and triggers the filters envelope.
In the case a synth has a separate envelope
generator for the VCA too, this envelope is been triggered also and the
envelope opens and closes the VCA by its "shape" as also the filter
cutoff frequency is modulated by the filters envelope generator ( filter
contour ).
The trigger ( gate ) wave of the MPU-101
is a 5V positive pulse or square wave.
If you hit a key on a midi keyboard, the note
number represented by midi is converted to a voltage representing the
related pitch at the MPUs CV-OUT.
The moment you hit this key ( midi note on )
is converted by the MPU to a rising 5V voltage ( gate open ) and if you
release the key this voltage falls down to zero volts which is ( gate closed )
midi note off or Midi note off=vel 0 .
The time between depressing and release of
any key the gate voltage remains 5V+ and that is the hold time of the gate (
as long a key is held down ).
It´s been a long time ago I´ve played a ARP
Odyssey white face in the end of the 70th and there was no Midi at
all.
So I can´t remember exactly what kind
of additional inputs the synth has on the back.
In any case you should connect the CV-out of
the MPU w/ the CV-in of the synth...( if it accepts 1V
per oct.)
the Gate-out of the MPU w/ the trigger in of
the synth ( if it accepts 5V positive trigger/gate )...
If you have more inputs for the ARP, maybe CV
for Filter cutoff, Frequency modulation inputs for the oscillators, CV inputs
for the VCA, you can use these in several ways w/ the
MPU-101.
The "dynamics" out of the MPU can control the
filters cutoff or / and ( Y-cable or multiplier ) the VCA to make the
synth ;velocity sensitive for colour and loudness.
With the separate Bend ( Pitchbender ),
Modulation ( Vibrato ), AT ( After touch ) and VOL ( volume control ) outs of
the MPU you are able to control different more to be modulated modules of your
synth.
These controllers are related to your
midikeyboard but the resulting control voltages ( CVs ) can run to anywhere
into you synth if enough inputs are available.
>As far as I read online - several people are using the
MPU-101 with the Arp Odyssey, but
>apparently I can't. I just hope the
CV/GATE in my Arp isn't dead.
You
never used the gate / trigger the right way it seems, - so it couldn´t work
anyway until now... :-)
>Can anyone of you cleaver ppl help me?
Check it out the way above and try to find out
first which voltage-signals your ARP accepts.
Sometimes a mod helps !
>Thanks,
>Michael.
PeWe