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Gear / Technical Help => Cables => Topic started by: thunderbolt on May 01, 2015, 11:50:49 PM

Title: Wiring for a direct insert cable
Post by: thunderbolt on May 01, 2015, 11:50:49 PM
I have pre-made TRS > XLR F short (6" dongle) cables that I'd like to use on soundboards with limited outputs (and in one case a board in which the operator as of yet hasn't figured out how to send me a stereo out buss).  So I'd like to use them on insert jacks used for effects.  There are multiple old threads, and I'm looking for some clarity.  I don't want to do the insert-halfway method for multiple reasons.  I asked a fellow board member who had weighed in previously on this.  He told me:

"Insert cables send out of the board on the tip of a TRS connector. The return comes back to the board on the ring with ground on the sleeve."

Ok, that seems clear.

"Take a TRS to MXLR cable and short the tip and ring together with a small jumper. You can also do this at the xlr end by shorting line 2 and 3.  Now your 1/4 send and returns the insert signal while splitting the signal to the FXLR."

The question:  Instead of shorting tip and ring on the TRS, can I accomplish the same thing by soldering a jumper to XLR pins 2 and 3?  The TRS is encased in molded plastic and for ease of modification, it would be much easier to disassemble the XLR and modify that.  Would that arrangement result in a cable that would allow me to receive/send?  I also realize this would now be unbalanced, correct?  Any implications other than keeping the cable as short as possible?  It would be going into a pro deck.
Title: Re: Wiring for a direct insert cable
Post by: tim in jersey on May 02, 2015, 12:25:29 AM
Maybe the pin-outs on this diagram will help?

http://www.taperssection.com/reference/pdf/DIY_CableDiagram_connettori.pdf
Title: Re: Wiring for a direct insert cable
Post by: ScoobieKW on May 02, 2015, 01:52:33 AM
Either end will work. Electrical path is the same.
Title: Re: Wiring for a direct insert cable
Post by: 2manyrocks on May 02, 2015, 10:09:26 AM
Seems like the manual for Mackie mixers goes into some detail about recording from the direct outs.  As I recall, they recommend inserting one click and that's what I've done with some reservations about someone yanking them out by accident. 
Title: Re: Wiring for a direct insert cable
Post by: thunderbolt on May 02, 2015, 12:19:18 PM
Thanks everyone.
Title: Re: Wiring for a direct insert cable
Post by: Tom McCreadie on May 03, 2015, 03:28:01 PM
Mike Rivers - who authored some of the Mackie manuals, and also published a "Mackie Compact Mixer Reference Guide" - has elaborated on this "best way to insert" topic, on various occasions in r.a.p. newsgroup threads.

For instance, here's his explanation from a thread of 2006:
====================

mcmillan@engineous.com wrote:

> The mixer has no per-channel line-level outputs except for the INSERT
> jacks.  But plugging a 1/4 mono (e.g. unbalanced) plug into the INSERT
> jack cuts out the signal.  If I partially insert the mono 1/4 plug into
> the INSERT jack I can get both a signal to the recorder and the signal
> through the board.  But that is an awful setup - any slight bump of the
> plugs and we either lose the recorder signal or the live signal.  Ugh.

It indeed looks suspicious, but you'd be surprised at how many people
work this way without a problem. You just have to be careful. However .
. .

> Any sugggestions on how to configure this?  Will a 1/4 inch
> stere-to-mono adapter do the trick?  I assume it just needs to short
> the right/left channels of the stereo plug to prevent the board from
> losing the signal?

That's exactly what you need to do, however, sticking a stereo-to-mono
adapter on to the plug adds another couple of inches of lever to what's
straining the jack.  If you don't properly support support the cable to
take the weight off the jack, you'll have a jack failure sooner than
later

What you really need to do (you can't buy this off the shelf) is build
some cables that have a TS plug on one end and a TRS plug with the tip
and ring terminals connected together on the other end. Buy half as
many 1/4" TS cables as you need, but twice as long as you need. Get as
many TRS plugs as you need. Cut the cables in half and solder the TRS
plugs on to the cut ends.
==========

After I encountered my first intermittent signal failure, I stopped using the half-insert method for all critical recordings [<= but aren't they all?   :-) ]

 
Title: Re: Wiring for a direct insert cable
Post by: cybergaloot on May 04, 2015, 08:25:06 AM
Seems like the manual for Mackie mixers goes into some detail about recording from the direct outs.  As I recall, they recommend inserting one click and that's what I've done with some reservations about someone yanking them out by accident.

This does not work for all soundboards.
Title: Re: Wiring for a direct insert cable
Post by: ScoobieKW on May 04, 2015, 03:52:00 PM
Seems like the manual for Mackie mixers goes into some detail about recording from the direct outs.  As I recall, they recommend inserting one click and that's what I've done with some reservations about someone yanking them out by accident.

This does not work for all soundboards.

True, and it's a sketchy unsecure connection. Build the adapters.