Wiring patchbays fairly neatly -a 'How-To'

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SSLtech

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Jun 3, 2004
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As a spin-off from a thread in the Brewery, I thought I'd consolidate everything into a single 'Lab' thread...

So, here's a brief rundown on how to NEATLY wire snake cables to TT patchbays.

In this case, the cable is Mogami 24-pair shielded pair, and the patchbay is a Switchcraft 96-point TT bay. This particular patchbay example which I'm wiring doesn't call for any  normalling, so no normalling is shown; -I'll try to take some more pictures and add them in with descriptions later on, next time I have to wire some more of those.

PREPARATION  IS KEY.
If the prep is sloppy, the job will be sloppy. Take the time to prepare carefully and neatly, and the finished result will be all the neater.

First, you take some adhesive paper 'console tape' and lay it down on your patchbay, and mark the center position of each socket.

Like so:
IMG_7200.jpg


-Here's a close-up:
IMG_7201.jpg


-Then you number the points...
like so:
IMG_7202.jpg


IMG_7203.jpg


..Then you take your piece of marked tape, and use it as a cutting guide, to pre-cut your unsheathed and 'combed' pairs to length...

-Like so:
IMG_7204.jpg


Continue doing this for all the snakes, Then once they've all been pre-trimmed to length, strip and tin the individual pairs, to a reasonably uniform length. I prefer about 18mm (3/4 inch) for the sleeve, and about 3mm (1/8 inch) for the conductors.

If the grounds are being kept individually isolated, then the drain wires should be sleeved leaving about the same 3mm length exposed, but in this case we're using a bussed ground, so the drain wires are simply tinned all the way back.

GROUND BUSSING

One of the nice things about Switchcraft solder patchbays are the 'offset' holes in the ground terminals, which allows you to thread a piece of buss wire from side-to-side, threading it through the 'eye of each ground terminal, like so:

100_1667.jpg


In this picture, I've also lightly splashed each of the ring and tip connections with some solder, to get things started, but the ground contacts are fully soldered to the ground bussing. (This is for inclusion in a new SSL console installation, and all SSLs have bussed grounds for everything except the mic lines.)

So now our patchbay is ready for attaching the wires:
100_1668.jpg


Start by attaching each pair, beginning at one end and working all the way to the other. -Take care to 'comb' the pairs out as you solder each one; make sure that each one is free from tangles all the way back to the overall snake jacket.

Use heat-shrink tubing for every connection... -EXCEPT the ground connections in a bussed-ground installation- and ensure that the tubing slides easily on after each solder joint has cooled. -In this instance I'm using clear heat-shrink tubing, so it's not easy to see, but everything except the drain wire is sleeved and insulated. -This makes any shorts or strand-bridges a practical impossibility, and pretty much eliminates the need to go back in and chase down problems afterwards.

Here's how it starts:
100_1670.jpg


-And a zoomed-out shot a little over half-way through the first snake; this time from the other side:
100_1671.jpg


Here's the first snake all soldered-up. -Notice how the pairs all fall neatly and tidily to length:
100_1673.jpg


...and here's another shot after having attached a second snake to the adjacent row of sockets:
100_1674.jpg


STRAIN RELIEF/DRESSING

Take a little time now to slip on a few slim cable ties, and 'dress' the pairs neatly. Don't tighten them all up as soon as you put them on, slip them on loosely, and 'guide' the pairs into a nice tidy order as you go... only once they've started sitting perfectly neatly should you tighten them completely.
100_1675.jpg


Here's the completed half of the patchbay after cable-tie dressing:
100_1676.jpg


...and from another angle:
100_1677.jpg



...So, from there on, it's just a question of repeating the process for the remaining half of the patchbay:

100_1678.jpg


100_1679.jpg


...the lower row complete, and strain-relieved while the upper row is started:
100_1680.jpg


100_1681.jpg


...the upper row completed and dressed/tied off.
100_1682.jpg


-A closer look at the finished job:
100_1683.jpg


Some people (including myself) like to use lacing cord instead of cable ties. -It's a dying art, and something I'll occasionally do if there's NO possibility of anyone wanting to re-work the patchbay later. -If you're using this as a 'how-to' guide for wiring your first patchbays, now is probably NOT the time to attempt to learn how to use lacing cord... Start with cable ties, and -if you develop a perverse enjoyment from the 'Zen' of patchbay-wiring, then by all means look into it for the future.

Here -once more- is the back view of a patchbay which I wired a few years ago:
Patchrear1.jpg


Keith
 
A note on cable-exit sides:

If you're planning a BIG patchbay installation (as on a full-sized console for example) it's often a smart idea to have each strip have all the wires exit from one side or the other... but PLAN IN ADVANCE to ALTERNATE the side from which the cable exits.

-This makes pulling the patch strips easier for service. (You DID leave an extra couple of feet's slack in the snake for service acces, -right?!?)

If you're wiring two 48-pair overall-jacketed/sheathed snakes however, it's SUPER-neat to have each snake enter from opposing ends, so that the 'gaitor' of cable-tied pairs is a constant width over the entire patch width... instead of having 96 pairs at one end tapering down to zero pairs at the other...

Keith
 
Oh nice, thanks!

I recently did a studio with a Neutrik one and this is very cool. I remembered what you
were telling me about patchbays when I went at it myself later in Switzerland...what
a mess ;)

Next guy wants me helping with assembly and installation of an entire Harrison plus
vintage synths galore, fun...
 
That's a work of art...wish I had bothered to use heat shrink when i did mine recently...thankfully they are trs jacks and there's a good distance between everything so I'm not too worried...should i be worried?
 
Showoff! ;)

Excellent stuff Keef.  We gave up on the solder-type bays a few years ago.  We've been using the Audio Accessories bays with the 3-pin EDAC rear connectors since 2006.  It's a marvelous time saver.  I've got a spreadsheet to plan snakes, and pass it along to Redco to make them.  Then I just snap everything in place.  The best part is when it's time to move a room or gear around.  Just a mere pluck and it's off to new location on the bay or a new rack.  It makes sense for a small, growing studio. 

However, if I had a real console and my racks figured out, I'd do it your way.  Seems the type of work that clears your head after you get rolling and looks amazing when you're done.
 
Neat guide!

I ended up making nearly half of the mistakes you specifically warn against there. Oh well, next time then.

Here's the original thread by the way: http://www.groupdiy.com/index.php?topic=38379.0 Good working method and mistake related discussion there.


One thing that might actually help that was not mentioned above: on mosses and mitchell and other canford b-gauge patchbays each jack can be separately removed. It's just one screw per jack. This avoids all the poking around in the very confined space behind the strain relief bar.  Good for my clumsy fingers for example. I lined up the removed jacks on the table for far easier working.

Which brings me to a question. What is the use of the bus bar here, something specific to the SSL console you mention? Is the bar itself connected to something on the SSL desk?

I can also do that for the misc. usage patchbay I have, but I just could not think of a valid reason to do so yet.
 
just saw some patchbay work on gearslutz a few days ago too

mosses and mitchell
http://www.gearslutz.com/board/photo-diaries-recording-studio-construction-projects/341598-bridge-recording-studio-build-16.html

check out the page after that too for some extreme back of rack porn!
 
I knew about that place going in and I can only wish them the best in this day and age. It's a big undertaking from a financial point of new and it's obvious they didn't cut any corners. I hope they can survive in this economy.
 
Ground wires are BUSSED on every SSL console patch strip apart from mic lines... always have been.

Since every wire and its neighbour is ALREADY at the same potential as the buss wire which links them there's no electrical reason to isolate, -quite apart from which it makes it impossible to slide a piece of heatshrink over the contact.

TWO reasons!  ;D

Keef
 
SSLtech said:
Ground wires are BUSSED on every SSL console patch strip apart from mic lines... always have been.

Since every wire and its neighbour is ALREADY at the same potential as the buss wire which links them there's no electrical reason to isolate, -quite apart from which it makes it impossible to slide a piece of heatshrink over the contact.

TWO reasons!  ;D

Keef

cool now I know.
 
SSLtech said:
Since every wire and its neighbour is ALREADY at the same potential as the buss wire which links them there's no electrical reason to isolate

Good to know.

I certainly won't bus my grounds here "by default" then. Sure most of the gear I have is correctly balanced and transformer isolated, but who knows what kind of weird unbalanced patches will be required in the future. I can imagine a bus bar inviting all kinds of noise for those connections.
 
Hi, Thank you for the tutorial! Is there any change to get the pictures in better quality? It seems that linked pictures are missing..?

//Henrik
 
> It seems that linked pictures are missing..?

Obfuscated.

I find (on these images) that if I Right-Click and View Image, I get a clear image. Try that.
 

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