Update: 8 16bit cv outputs from computer!

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mmp
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Post by mmp » Thu Sep 17, 2009 8:49 pm

Thanks for posting these.

Regards,

MM

criticalmonkey wrote:btw - anybody wanting to give this a quick try - i made some really ugly bad vst plugins for demo purposes on criticalshit.com
gate/adsr/midi to cv using the audio interface/and an lfo - pluggo format so you'll need the runtime
great way to test your interface

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macumbista
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Post by macumbista » Tue Nov 10, 2009 3:17 pm

Hmmmm..... the Hammerfall DSP soundcard is sitting with it's case open and boards exposed on the workbench. There are 16 big electrolytics on the output board, probably two for each of the 8 channels (positive going and negative going voltage). Is it really just so simple as to short these to get DC coupled output??????

I think I'll sleep on the idea for a night and see how it strikes me in the morning. Anybody wanna try to convince me one way or the other? :twisted:
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wetterberg
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Post by wetterberg » Tue Nov 10, 2009 5:54 pm

try shorting out the last output only. Try it out on there.

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macumbista
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Post by macumbista » Sat Nov 14, 2009 7:06 pm

The deed is done. A very simple mod to short the output caps, and it works f*ing great!!!!! Plugging the output of the card into the 1V/Octave input of the synth, and using Pd to send DC voltage between -1 and +1 (limits of DAC), I get a very wide range from the oscillator. Output measures -5V to +5V on the multimeter (output levels of the Multiface are set by internal jumpers to -10dB or +4 dB, I have them at +4dB). Why didn't I do this two years ago???

(PS...Multiface I has balanced inputs & outputs, which explains why each channel has two caps.)

Time to start writing more Pd patches to do stochastic/generative sequences. I've been interested in creating some tendency masks to generate gates and notes lately (since I saw the note-generating software that Zbigniew Karkowski uses in a composition workshop he gave here in Berlin last week). All this stuff is so much easier on the computer than analog style, so why not use each machine for what it's good for...
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thelizard
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Post by thelizard » Mon Nov 16, 2009 3:47 pm

As a Max and M4Live user, this is about the most damn exciting thing I've seen in a while.

Can anyone tell me if the Digidesign 002R outputs are DC-coupled? Apparently, the headphone jack is (of all things... is it because most headphone plugs are TRS?), but I can't find anything about the rear outputs. I would test it, but I'm afraid of bricking anything.

What really pisses me off is that I just ordered a gigantic batch of TS 1/8" cables and adapters for 1/4" (going both ways) from DeepSurplus and paid like $10 shipping. Had I known about this sooner, it would've cost me a few dollars extra to experiment with TRS jacks, instead of an extra $10 for a new order. :bang:

Student budgets suck.

aleatoric
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Post by aleatoric » Sat Dec 05, 2009 12:16 pm

Hey thelizard, did you find out if the Digi 002R will work?

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Post by aleatoric » Sat Dec 05, 2009 1:38 pm

From what I could find on the Volta sites, the 002R like most audio interfaces uses DC-blocking capacitors on the outputs.

I am tempted to open it up and see how difficult it would be to remove.

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wetterberg
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Post by wetterberg » Sat Dec 05, 2009 5:15 pm

aleatoric wrote:From what I could find on the Volta sites, the 002R like most audio interfaces uses DC-blocking capacitors on the outputs.

I am tempted to open it up and see how difficult it would be to remove.
no need to remove them, from what I gather - just short them out.



I just upgraded from a motu828mk1 (!) to a motu UltraLite mkIII, taking advantage of its replacement coming soon. (I don't want your stinkin' usb connection! pfft!) - so yeah, I'm looking forward to having a portable, incredibly nice sounding unit for doing these things.

Also, I'll be able to do weird shit with TWO computers now, hehe.

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criticalmonkey
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Post by criticalmonkey » Sat Dec 05, 2009 11:12 pm

be careful with the digidesign interfaces if you depend on protools
not sure of le but hd software and hardware are heavily tied - software won't work with a "faulty" interface

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Post by aleatoric » Mon Dec 07, 2009 12:57 pm

Yeah that's what I am afraid of. Although it's no longer my primary Digidesign interface, and i suppose it would be just as easy to reverse any mods I make to the outputs? Or would I be better off selling it and picking up a used MOTU 828?

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wetterberg
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Post by wetterberg » Mon Dec 07, 2009 3:00 pm

I believe that whatever donglism DigiDesign put in place to tie the hardware to the software won't be affected by shorting out capacitors. And yes, removing the short would return it to normal.

Also, the 828mk1 may work, but it certainly ain't no modern audio interface, if you follow me. It's a ten year old design.

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1nput0utput
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Post by 1nput0utput » Mon Dec 07, 2009 5:45 pm

I've tested a Digidesign 192 and an Mbox. Neither one has DC-coupled outputs. Based on that, I'd expect that the 002 doesn't either.

For those who have successfully modded an interface to bypass the DC-blocking caps, I'd be interested in seeing pictures. I tried to figure out which caps to short on a spare Mbox, but I couldn't get it to work. Maybe if we see how you did it, we'll be able to figure out how to mod other models. It would be great to have a list of interfaces where this mod was successful, and each item could have a picture highlighting which caps to short.

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wetterberg
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Post by wetterberg » Mon Dec 07, 2009 8:37 pm

Perhaps if you post up some clear pictures of the mbox pcb we can discern which caps you'll want to fiddle with?

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