Volta - cabling question

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Discussion related to installation, configuration and use of MOTU hardware such as MIDI interfaces, audio interfaces, etc. for Mac OSX
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heddhunter
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Volta - cabling question

Post by heddhunter »

I have a MOTU 828 mk 2 that I would like to use with Volta to control a Sequential Pro One and a Yamaha CS15. After reading the manual, I have no idea what sort of cables to use and I am terrified that I am going to fry my interface. Any suggestions?

Thanks!
1nput0utput
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Re: Volta - cabling question

Post by 1nput0utput »

The situation is that the interface outputs have three conductors (tip, ring, and sleeve) and the CV inputs on most synths have two conductors (tip and sleeve). MOTU's recommendation is to leave the ring conductor of the TRS plug disconnected. So you would have a cable wired liked this:

TRS plug.......TS plug
tip------------>tip
ring----------->no connection
sleeve--------->sleeve
The leading cause of wrong answers is asking the wrong questions.
heddhunter
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Re: Volta - cabling question

Post by heddhunter »

1nput0utput wrote:The situation is that the interface outputs have three conductors (tip, ring, and sleeve) and the CV inputs on most synths have two conductors (tip and sleeve). MOTU's recommendation is to leave the ring conductor of the TRS plug disconnected. So you would have a cable wired liked this:

TRS plug.......TS plug
tip------------>tip
ring----------->no connection
sleeve--------->sleeve
Thanks for the reply. Forgive the naive question but if I get a TRS to dual TS cable like this one http://www.topdjgear.com/ho9trs2tsca.html can I just plug in the sleeve side and leave the ring wire dangling (or snip it off)?
blink
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Re: Volta - cabling question

Post by blink »

So this is my question on the same topic. How do you go about leaving the ring unconnected aka "floating"? Do you a.) plug it half way in
b.) just plug in a normal trs into the ts jack because there is no ring connection in there
or... c.)none of the above

(if c please explain what to do)

Not trying to be snarky but everywhere gives these "just leave the ring unconnected" answers and that goes nowhere if you don't know how to do that. You know what I mean?
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HCMarkus
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Re: Volta - cabling question

Post by HCMarkus »

Question: How do you go about leaving the ring unconnected aka "floating"

Answer: You make you own cables. It is very easy and will save you lots of money, too. :wink:

Answer 2: Use TRS to TRS cables. The Ring on the TRS Plug inserted into your TS CV jacks will float automatically... as you correctly surmise, there is no contact that makes the Ring connection in a TS jack. TS jacks are just stripped-down TRS jacks: the same jack minus the Ring contact.
blink
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Re: Volta - cabling question

Post by blink »

:shock: You are the most straight up mofo on the internet at this moment. For some, reason nobody is saying use a trs to trs cable. Cv's are tip and sleeve with out the ring, no problem. TY..TY.TY
I just got Volta today and saw that in the manual but could not find a simple straight up solution and did not want to destroy or compromise my equipment. How can their be a detail like that included with the manual with no solutions? I just wasn't sure if the ring would interfere with the CV inputs. Great now I can get to using it!
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Re: Volta - cabling question

Post by blink »

Is there any type of noise caused by using trs to trs?
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HCMarkus
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Re: Volta - cabling question

Post by HCMarkus »

blink wrote:Is there any type of noise caused by using trs to trs?
Answer: Yes.
Details:
1. The mechanical sound that happens when you plug the cable in.
2. Other than that you should have no issues, unless you pick up a local radio station or something. But you'd probably get just as good reception with a custom TS to TRS cable. By the way, even if you do get a little noise pickup in your unbalanced CV circuit, it won't be heard (unless you like listening to control voltages). Unless you cause a ground loop, which would happen regardless of the cable - unless you dealt with it by making a custom ground-lift cable, as is discussed here:

http://www.rane.com/note110.html

As you will note, when compared to a TS cable, a TRS cable simply adds a second wire inside the shield. It is twisted into a pair with the other wire inside the shield, which yields tremendous benefits when operating with balanced audio gear. It won't be an issue for you in your situation. In all honesty, you could probably use a standard TS - TS cable with no detrimental effects. All the MOTU gear allows users to plug audio TS cables into TRS jacks. You get a drop in S/N ratio and level, and you lose the benefits of balanced lines, but it works fine for things like keyboards and such. I am not sure, however, how the MOTU interfaces handle the DC Control Voltages you are working with. So you might as well use TRS.

Sincerely,

Straight-Up MoFo. :)
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