Rewire Used TT Patchbay for Thru, Half, Norm?

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ioplex

New member
I have a slowly growing array of gear and so I was thinking it would be great if I had a TT patchbay.

So I was looking at an ADC 104NMKII jackfield on Fleabay. It has two fairly long bundles of cable with a punch plate on the end. I thought I could just cut the cables at the punch plate and then solder on TRS, XLR, spades or whatever I need for various gear.

Here are the questions:

1) Can this type of patchbay be reconfigured between non-normal, half-normal and full?

2) When adding to the wiring harness, how does one get to the back of the patchbay to solder things? Do you

a) put on overalls and dig-in with the soldering iron or
b) take the entire harness out to the bench or
c) remove some jacks, wire them and then just screw them back in?

3) The alternative is to get a standard switchcraft TT patchbay with solder lugs, buy some cable and just create a harness from scratch. Where can I get good patchbay cable? Specifically, it looks like 2 conductor with shield as ground but with a thin jacket is used? Where can I buy a spool of this cable?

4) Is it not uncommon to use cable with more conductors to make a single cable with multiple connectors tailored for a particular piece of gear just to minimize the bulk of the harness, make it cleaner and clearer as to how to hookup?

5) Would it be ridiculous to use shielded CAT6 to make multi-connector patchbay harness cables (at least 2 balanced but 3 if a ground can be shared or even 4 or more if signals are unbalanced)?
 
I have a slowly growing array of gear and so I was thinking it would be great if I had a TT patchbay.

So I was looking at an ADC 104NMKII jackfield on Fleabay. It has two fairly long bundles of cable with a punch plate on the end. I thought I could just cut the cables at the punch plate and then solder on TRS, XLR, spades or whatever I need for various gear.

Here are the questions:

1) Can this type of patchbay be reconfigured between non-normal, half-normal and full? That depends on the type of punch field it has at the end of the wires.Some have 5 punches per channel. The way you jumper back there sets normals. Find the manual online.

2) When adding to the wiring harness, how does one get to the back of the patchbay to solder things? Do you

a) put on overalls and dig-in with the soldering iron or
b) take the entire harness out to the bench or Thats what i do. Its going to be a chore so might as well get comfortable.
c) remove some jacks, wire them and then just screw them back in?

3) The alternative is to get a standard switchcraft TT patchbay with solder lugs, buy some cable and just create a harness from scratch. Where can I get good patchbay cable? Specifically, it looks like 2 conductor with shield as ground but with a thin jacket is used? Where can I buy a spool of this cable? Look for "shielded twisted pair", I use Beldon mil-spec that has 18awg silver wire in teflon insulation.

4) Is it not uncommon to use cable with more conductors to make a single cable with multiple connectors tailored for a particular piece of gear just to minimize the bulk of the harness, make it cleaner and clearer as to how to hookup? If you mean like a piece of equipment that has several balanced inputs and/or outputs, then you would want to find a cable that has multiple shielded twisted pairs. This is the type of construction you find in microphone snakes. (expensive as the count goes up)

5) Would it be ridiculous to use shielded CAT6 to make multi-connector patchbay harness cables (at least 2 balanced but 3 if a ground can be shared or even 4 or more if signals are unbalanced)? I wouldnt. Cat 6 cable in AWG 28 wire, too small. And the wires are solid strand, meaning the will break if bent back anf forth very many times. Dont share shields.
 
mdainsd said:
3) The alternative is to get a standard switchcraft TT patchbay with solder lugs, buy some cable and just create a harness from scratch. Where can I get good patchbay cable? Specifically, it looks like 2 conductor with shield as ground but with a thin jacket is used? Where can I buy a spool of this cable? Look for "shielded twisted pair", I use Beldon mil-spec that has 18awg silver wire in teflon insulation.
Click to expand...

18 AWG?! Is that necessary to run microphones or guitar signals through the patchbay? Or to drive speakers? I think that might be a little overkill for my purposes. Everything is line-level. At least I wasn't really thinking about running mics and guitar through the patchbay.

What about Mogami 2549 for a patchbay? That seems to be what comes up after Googling for a while. That also seems a little bit overkill though.

I see what you mean about the 5 conductor wire in those ADC patchbays that allow programming on the punch panel. Yeah, I guess I don't want that.

If it was an ADC unit that just had 3 connections per channel on the punch panel, do you know if the jacks can still be modified for normal / half / thru? Or would they just be hardwired for half or whatever?

The ideal situation would be to find one of those ADC units but with lots of 3 conductor wire inside. They look like they have a LOT of extra wire (I guess so they can be re-wired over and over?) so I could just cut off the ends at the punch plate and solder on whatever connector I need and then it looks like it would reach anywhere within the rack or even a rack adjacent to it. That would save a lot of soldering.

BUT. It would only work if the jacks in a non-programmable ADC patchbay can be changed between normal / half / thru. Meaning are there leads for the switching contacts with wire that can be changed or what. That is the question ...
 
The short answer is yes. most TT patch bays for audio use have enough terminals on the back side to connect Full normal, half normal or no normal. (It gets fun with the 144 point TT bays) I messed up once and bought data TT patch bays,no shield connections at all, worthless for audio. the back side of TT bays usually has either solder lugs or "tails" that are for use with wire wrap terminations.

18awg may be overkill, but that is what I use. Speakers get 4awg, thats just me though.
 
ioplex said:
If it was an ADC unit that just had 3 connections per channel on the punch panel, do you know if the jacks can still be modified for normal / half / thru? Or would they just be hardwired for half or whatever?
...
BUT. It would only work if the jacks in a non-programmable ADC patchbay can be changed between normal / half / thru. Meaning are there leads for the switching contacts with wire that can be changed or what. That is the question ...
Click to expand...

Just for posterity I'm going to answer my own question and report that after Googling the subject, it appears that the ADC units may not be modifiable. The jack can be such that the normal contacts are connected to the other jack with metal that is part of the contact. So they cannot (necessarily) be modified from being half to normal or thru or whatever.
 
A couple of points, if I may...

While expensive, and they may not meet the "real men" criteria, there are TT patchbays that are readily switchable between full/half/none normally and different grounding schemes that use DB-25 connectors on the rear. And you can buy DB-25 x 1/4" / XLR / DB-25 or whatever snakes. But, Switchcraft bays are about $1,000...Audio Accessories are around $700...short DB-25 snakes run from $35 or so up (and mostly up).

But, if you're just getting started with a patchbay, you might consider a 1/4" x 1/4" bay...they use 1/4" TRS patch cables, and connections on the rear are also 1/4" TRS...normaling is usually via: small switches...Neutrik gets a lot of love...I've got a Behringer that I've had for 7 or 8 years with no problems, dbx and Samson also make units, they run $75 - $100. One nice thing about the 1/4" units, you get to find out how many ways there are to screw up a patchbay layout without spending a lot of time or money.

Personally, I wouldn't go more than two 1/4" patchbays before moving to TT stuff...downside of the 1/4" units is you only get 24 jacks per row vs 48 with the TT units, and they don't stand up to a lot of plug/unplug cycles like the TT stuff does, but they're fine for getting started.

A little something to think about...
 
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