Expansion I/O

[bsmith23]

I'm using the Lexicon mpx500 hung off of my digi 002 s/pdif and it works great, however I would love to have more cv outputs. Am thinking there must be some dc coupled 8 channels of I/O that has adat light pipe out there which isn't listed in the compatibility document. I've read a bit about the possibility of modding old adat decks to do this - is there anyone out there who's done this or is aware of some unit that can expand the available voices in the manner the lexicon mpx500 does, but with more channels, and over lightpipe? The only motu piece that the product literature says 'expandable over light pipe' as opposed to firewire is the 8 pre, which doesn't give the desired outputs - is it known if other compatible motu devices can be chained via lightpipe?.

*edit* digging around it looks like this may be possible with most of the motu stuff. Is anyone doing this? Using a motu interface as an I/O expansion for another interface over lightpipe?

[bsmith23]

I stumbled on a new motu traveler (not mk3 - mk1?) which was being sold on clearance at guitar center and picked it up to see if I could get it working as mentioned in the previous post - similar to how the lexicon uses s/pdif, but using the adat lightpipe on my digi 002 in pro tools and running it in a standalone configuration, taking just adat input to just it's analog outs.
It almost kind of works. Calibrates to about 4 octaves of pitch- (my lexicon gets close to 8, and I recalibrated with it again after all this with identical synth setup just as a sanity check) but the gate is really weak - I have to crank the gain on my vca to the point that it's sitting there droning before the gate will fire off. Gain is cranked on channels in question and doing hard panning, etc..
I don't know if this is just how it is with this version of the motu traveler, or something to do with using the lightpipe or what. Would love to know. Oh well, back to gc it goes, unless there's a suggestion of something else to try. Damn.

***Added It looks from poking around on different forums like all of the 'mk1' devices have a lower voltage output than necessary to reliably use, although there is an 828 listed on the compatibility page. Is it looking like motu remedied this for all the mark2 devices? Totally want the additional voices and don't want to go through this exercise again - seeing some affordable 828mk2 and travelers out there, I think the lightpiped off digi 002 thing will work with the right device....

[os]

According to the specs the Traveller mk1 should put out ±3V which is not too bad - it should give you about 6 octaves.

828 mk1 is only ±2.3V so that's barely usable.

It seems there's a clear gap in the market for a lightpipe->DC-coupled conversion box, which I've recognised and am trying to do something about. More than that I can't say right now.

[bsmith23]

On this traveler I dug a little deeper, it appears the main outs 1 and 2 have weaker outputs that the others (and the others are inconsistent on output as well) - I was able to get it to 6 octaves using 3 + 4, gate is a tad better but still weak - was able to get it there by using an stg .bam mults gain on it's attenuator. But to heck with burning that just for gate. At the very least this has shown me that with sufficient output the lightpipe deal does work. Back to guitar center it goes... Incidentally I've seen references in posts to a chart that shows output levels on various interfaces, but can't seem locate it - can someone provide a url if they have this bookmarked?

edit found it: http://pics.livejournal.com/revstate/pic/0000xp45

[UltraJv]

Would it be worth adding either 2 diodes or a full bridge rectifier + smoothing capacitor to the audio outputs of a standard card to give DC? You will lose around 1v but it might work if the output is high enough.

[os]

Oddly enough this came up on Muff's almost simultaneously:
http://www.muffwiggler.com/forum/viewto ... 894#179894

I think this is well worth a try.