Using MOTU Volta to control Studer VCA automation

[malu]

Hello!
I have a Studer 903 mixing console fitted with VCA faders. The original Mastermix MX644 automation computer is missing, and I think that trying to track it down in the used market could be not worth the effort.
On the other hand I'd really like to take advantage of the desk automation, so I came up with an idea: using MOTU Volta to send control voltages to the VCA faders through a suitable audio interface. Being able to write automations in Digital Performer for the Studer desk would be really great!
Am I dreaming or is it feasible? What do you think?
Thank you,
Jacopo

[4stripes]

How did the original computer connect to the console to drive the automation? Is there a 'VCA input connector?'

It's possible but if there's no external connection into the VCA's, you'll have to break out IC datasheets, schematics, and a soldering iron--ie seek professional help.

[malu]

Hi 4stripes, there are three D-subminiature 37 pin connectors for automation send, return and write.
The input voltages for the automation return are 0V … +5,5V or -0,56 … +5V (selectable with jumper), as specified on the Studer manual.
Are these values compatible with an automation system based on Volta?
Thank you very much!
Jacopo

[4stripes]

I'm sure MOTU's Volta documentation would have this information. Or other Volta users. You'll need a voltmeter to measure.

[malu]

I'm sorry, but I can't find any documentation regarding output voltages on the Motu website.

[4stripes]

18 dBu is a common output level for a decent interface. You can see 18 dBu is 6.15 Vrms. So any 18 dBu or higher interface would produce enough voltage. Or if it's Vp-p the Studer wants, you can use an interface with as little as 8 dBu out.

[philbrown]

Volta was definitely buggy last time I used it (v1.04 I believe) and as near as I can tell not really supported by MOTU in any practical way. I can't really answer your questions, but I would suggest at least looking into Expert Sleepers as an alternative. He is very responsive to users and may have an answer for you. There are subforums for both on muffwiggler.com (a modular synth site) you may find useful.