TRS for standard Volta operation?

Discussion and support for MOTU's Volta software.

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1nput0utput
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Post by 1nput0utput » Tue Dec 15, 2009 10:26 am

I think that some of MOTU's XLR analog outputs are direct-coupled rather than cross-coupled, and that explains why you would want pin 3 shorted to ground. The voltage at pin 2 will be higher when pin 3 is shorted to ground than when it is left unconnected. If you have a device with DC-coupled XLR analog outputs, try it both ways and measure the voltage.

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mateo
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Re: 1/4" Stereo Jack to 1/4" Mono Plug Headphone A

Post by mateo » Tue Dec 15, 2009 7:47 pm

doctorvague wrote: Maybe I'm missing something, but I really don't understand why you non-DIY guys who want an easy cable solution aren't just buying TRS > TRS cables and snipping the ring wire on one end. Dead simple.
I'd like to just do this, but I haven't actually been able to find any 1/4" to 1/8" stereo cables that don't have molded connectors. If anybody has found any, let me know where!

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stevenclements
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Post by stevenclements » Mon Dec 21, 2009 3:32 pm

richardm123uk wrote:I had problems finding cables when I first got Volta. I had them custom made from a guy in Vancouver (Canada) and they are fantastic.

Website here http://www.theslygoose.com/
He actually lists them now... $12.50 each 1/4" TRS to 1/8" TS
life is a treasure... dig it!

ruke
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TRS VOLTA/SILENT WAY QUESTION

Post by ruke » Fri Jun 11, 2010 10:00 pm

Hi

I guess this should go in this thread...

I have MOTU 24i/o and want to run volta and or silent way around my studio.

For my workflow it's best for me to use a TRS - TRS patchbay. I have two questions if anyone would be kind enough to help.

1. Can I mod some channels of my DBX PB-48 patchbay rather than modding cables? Please see the pic. I've not soldered much but am willing to have a crack at it !

2. If the above is possible - Would the following degrade CV signal strength prohibitively:

MOTU => TRS - TRS [10ft max] => PATCHBAY (DeNormalled) with above
modification if possible => TS - TS [20ft max]

Many thanks !

Ruke

Image

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doctorvague
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Re: TRS VOLTA/SILENT WAY QUESTION

Post by doctorvague » Sat Jun 12, 2010 7:24 am

ruke wrote:Hi

I guess this should go in this thread...

I have MOTU 24i/o and want to run volta and or silent way around my studio.

For my workflow it's best for me to use a TRS - TRS patchbay. I have two questions if anyone would be kind enough to help.

1. Can I mod some channels of my DBX PB-48 patchbay rather than modding cables? Please see the pic. I've not soldered much but am willing to have a crack at it !

2. If the above is possible - Would the following degrade CV signal strength prohibitively:

MOTU => TRS - TRS [10ft max] => PATCHBAY (DeNormalled) with above
modification if possible => TS - TS [20ft max]

Many thanks !

Ruke
Rather than messing with your patch bay (which could work), if it were me I'd simply do this with your TRS-TRS cables:
doctorvague wrote:Maybe I'm missing something, but I really don't understand why you non-DIY guys who want an easy cable solution aren't just buying TRS > TRS cables and snipping the ring wire on one end. Dead simple.
With just a bit of trouble you can always resolder the end you snipped someday if you ever want to have them back stock.

ruke
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Post by ruke » Sat Jun 12, 2010 11:51 am

Hi there

Thanks for your response...

Without going into a long boring explanation with my set up it'd make a lot more sense for me to alter the patchbay rather than the cables....

That's kind of why I was asking the below - to see if the transition from balanced to non balanced over 30 ft would degrade the CV signal...
2. If the above is possible - Would the following degrade CV signal strength prohibitively:

MOTU => TRS - TRS [10ft max] => PATCHBAY (DeNormalled) with above
modification if possible => TS - TS [20ft max]
If anyone has an idea of how to float the ring on the patchbay that'd be great - I'm guessing that I could scrape off the tracks to the middle solder points - is this possible? If so would I do it on just one side or the in and out? (The de-normalling means it'll go straight through from front to back)

Thanks !

Ruke

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baltimoroder
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Post by baltimoroder » Sat Jun 12, 2010 12:35 pm

Well, you wouldn't "scrape" per se but cut using an exacto or jeweler's knife. This site might be helpful.

Also 24io for CV... Image

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doctorvague
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Post by doctorvague » Sat Jun 12, 2010 1:54 pm

baltimoroder wrote:Well, you wouldn't "scrape" per se but cut using an exacto or jeweler's knife. This site might be helpful.

Also 24io for CV... Image
Plug a TRS cable in and check continuity with a meter between the exposed ring on the cable and whatever trace on the DBX card that corresponds i.e. shows as a short or zero ohms. Even a simple continuity tester will work. Then cut that trace. I always check with a magnifier to make sure I've completely cut through the trace.

I would only do one then hook up cables exactly as you plan to and make sure everything checks out with a meter. Meter the Ring and sleeve of your source cable (the TRS end you will plug into the 24io) -it should NOT show a short if the ring is floating. Then meter the tip of the 24io TRS plug with the tip of your modular TS plug with both plugged into the card as intended - that should read as shorted. Ditto for both sleeves, they should read as shorted. If all that checks out you're good to go.

You shouldn't have a problem with cable length. Keep in mind you'll be calibrating anyway in the case of 1V/oct osc pitch which is the most critical and whatever tiny voltage drop is present the Volta calibration will 'take into account' so to speak. IOW the cable becomes part of the whole system that Volta is calibrating.

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os
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Post by os » Thu Jun 24, 2010 3:24 am

doctorvague wrote:You shouldn't have a problem with cable length. Keep in mind you'll be calibrating anyway in the case of 1V/oct osc pitch which is the most critical and whatever tiny voltage drop is present the Volta calibration will 'take into account' so to speak. IOW the cable becomes part of the whole system that Volta is calibrating.
That's true, but there's also the issue of noise when going to long unbalanced cables. Even then, that's unlikely to be a problem for CVs.

NB in this situation, the TRS-TRS cable run also counts as unbalanced, since it's not terminating in a balanced input, just joining up to the TS-TS section.

ruke
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Post by ruke » Thu Jun 24, 2010 6:02 am

Thanks for the responses guys...

I ended up making up a box with a db25 going to 8 TS jack sockets, multed to 8 1/8" jack sockets.

Will I loose significant voltage if I use the mults?

Worked out well in the end and I managed to avoid carving up the patchbays !

Cheers

Ruke

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minja
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Post by minja » Sun Jul 03, 2011 8:19 am

Hello,

Would this do the trick for me. I dislike soldering so off the shelf would be better.

http://www.thomann.de/ie/pro_snake_tpy_2003_kbb.htm

or this but snip the ring on one side

http://www.thomann.de/ie/pro_snake_20023_30.htm

I think this is okay but I am not sure.

Ken

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Bluebox
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Post by Bluebox » Fri Mar 02, 2012 8:24 pm

Just poking my head in here, as I've mentioned it over in the Expert Sleepers subforum... I hand-build high-quality synth patch cables, including 1/8"-to-1/8", 1/4"-to-1/8", and TRS-to-1/8" with the ring floated specifically for use with products like Volta. Feel free to PM me for details if you're interested :)

Cheers,
-ian

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