Author Topic: SSL patchbay wiring: Parts used and techniques Part 1  (Read 8636 times)


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SSL patchbay wiring: Parts used and techniques Part 1
« on: July 26, 2012, 05:56:25 PM »
First of all, I'll update this when required (and my memory returns) if I have left out any comments or got descriptions horribly wrong (please correct me if so). This started off as a description of one of my wired SSL patchbays but also overlaps with SSL history!

I thought you might like to see some pictures of my SSL patch wiring with descriptions of the genuine parts used. Although not my best effort (some of the cables are a bit tight near the ends!), the two pictures are of an SSL 96 way patch I rewired for a studio in Europe. I used existing SSL cable taken from some 56 way 5K Edac looms although, for the record, SSL used Elco Varicon connectors which are an Edac equivalent which is less well known but arguably better as it uses a harder plastic version unlike the softer material used for Edacs which could be more prone to failure after sustained use.

The jacks shown are Mosses and Mitchell chrome plated types as used from the early 1980's to around  the mid 1990's when SSL changed to a nickel plated version. Earlier Audioline types are easily identified as the two screws are much closer together (amongst other features which I will deal with in a separate post).

For this patchbay, I cut off the crimps and re-tinned the wires which are the standard SSL twin screened Brand-Rex cable (made by a Scottish company). The SSL part number is 31LO2318 and I have seen a Brand-Rex part, GT 752067, written on a reel.

I loomed the wires along the patch using the SSL type waxed lacing twine (not cord which I will mention in another subject). This lacing twine was bought by SSL in two sizes, a larger, approximately 2mm size, for the main patch wiring and other console looms plus a smaller size later on, especially for the 5K cassette pot looms which used less and different cable.

SSL used Hellermann products for their sleeving and cable ties for a long time although, cost cutting lead them to use Cabletec sleeves which are more difficult to use. The twin screen sleeve was primarily a H20 x 20 black sleeve. H20 means a 2mm inside diameter hole x 20mm in length and I think the H implies the sleeve wall thickness.

Although the Brandrex cable had red and black 7/0.2 core wires (not OFC until the early 1990's I think), for some reason they used a black sleeve for the drain wire rather than green which would have made more sense. SSL had custom lengths of the black drain wire sleeve made for different purposes. This was also a Hellermann product and had the prefix TH in front of the length. TH stood for a thin wall sleeve unlike the commonly used H version. They used TH30, 40 and 70mm lengths for various purposes. As an example, a TH10 x 70 drain wire sleeve was basically a thin wall 1mm inside diameter sleeve x 70 mm long as used for the SSL DL socket wiring. For the record, they also bought in TH05 and TH75 sleeves which were 0.5 and 0.75 mm internal core diameters respectively to act as fine sleeving for tinned copper wire when Kynar wire (the usual normalling version on patchbays) was not being used on PCB mods.

The H20 sleeves were applied with sleeve expanders, sometimes known as "virgin stretchers" by some wire people out there! Hellermann sleeve lubricant was applied to the sleeve which loosened it enough to expand it on the tool and fit it onto the cable. At a push, you could use washing up liquid instead (plus it cleans your hands!).

In my view, the sleeve should be 2/3 on the insulation and 1/3 on the wires exposed but, you can see from the first pictures that they seem to wire it half and half. I don't use heatshrink for this purpose as it takes more time, can move during heating and may have to be cut off if anything is replaced. In the US, heatshrink seems to rule over sleeving and I rarely see it these days but, heck, everyone has different techniques!

So, in my example, wires are soldered onto the patch jacks and the lacing twine is knotted around the wires one at a time (I'll try and show a drawing of this soon) to separate them out. Also, notice the green 32/0.2 screen wire which solders to one off the jack screen lugs and ends up at the copper bar running along the SSL console. This is terminated in a OBA (or M6) crimp spade or eyelet crimp. Earlier SSL patchbays used a 7/0.2mm wire instead, later followed by a 16/0.2 yellow/green version (unlike the UK AC earthing wire colour code which is green/yellow. I think that this was deliberately used to show the difference between the two types.

SSL actually had large looming boards with M6 bolts in to loom patchbays. The Brandrex cable was fed around a DL end bolt and loomed along the table which could be 3 to 4m long to the patchbay area with 32 to 56 shorter looming pins fitted (made by Panduit I think). Using custom made Brady labels, SSL labelled the end cables at the patchbay (i.e. A1 and A48) and obviously all the ones at the other ends to identify them. The cables were loomed with lacing twine and cut leaving the loom ready for terminating elsewhere in the SSL looming department to the patchbay jacks, Bicc, 104 way 651 Mrac connectors or DL crimps. SSL had a very expensive ITT DL crimping machine which stripped the core wires and fitted a crimp at the same time.

Back to my picture! My wires were loomed along the patchbay tie bar and left it at a convenient point. Don't exit all the cables at the same place as there will be a huge amount (maybe up to 112 wires) coming out at patch jack 25 for example. Separate each row or even the top and bottom on the same patchbay by about 8 jacks to avoid a cable jam in the same place! However, I have done this on my example in the pictures as I have made the whole loom low profile (ie about 1u in diameter to match the patch front height).

The pictures shown use the earlier version of the support bar which was a M3 threaded strut holding the tie bar (in this case, one I made from ali strip) which was normally a SSL black powdered coated product which I also have. 112 way patchbays had to have these struts as the jacks extended along the patch front past the fixing holes so, they were mounted in between the end top and bottom jacks.

Later on, SSL had steel triangular shaped versions made which screwed into the end of the front panel. These then secured the tie bar and were much stronger and were not as high off the front panel.

Notice I have used black tape rather than heatshrink to bind the cables together (I loomed them in two lots of 56 coming together at this point). In this instance, heatshrink is not required in my view. It takes more time, costs more, is not visible anyway within the patchbay area and can easily be taken off and replaced if more wires are added. Also, notice my use of cable sheathing. This make was used by SSL, mostly for external looms before they made custom Brandrex multicores in 16, 24 and 32 versions (but not in patchbay loom construction). This is far superior to the normal type supplied by various companies even today but not as well known and available these days. It has a much higher melting  temperature and a closer weave so you cannot see the cables as much.

This started off as a short post but got longer as I got carried away (perhaps I should be!). I'll write another one soon with more pictures of my wiring for SSL patchbays but, next time, a custom made patch for an SSL extension which got cancelled. This will show some different parts and techniques used.

In case you didn't realise, I have a lot of the SSL parts mentioned in this post such as front panels (mostly unused 48 way G series grey and Raven sparkle 56 ways), loaded patchbays, tie bars and supports, SSL Brandrex cable (including 16, 24 and 32 pair multicore), over 4,000 Audioline and Mosses and Mitchell bantam jacks plus Hellermann sleeves (0.05 to 10mm internal diameter), cable ties plus lots of Elco 56 way connectors, mostly free sockets as used on the 5K and the later Focusrite consoles oh, sorry, I mentioned the SSL competition (in the early 1990's) even though Focusrite only made about 10 consoles. On that note, we made all the frame channel 8 module buckets, centre sections, external racks and various modules!
I'll post some adverts shortly but, meanwhile, check out my website especially the SSL and patchbay menus. If you see the website update menu first, all recently added or changed items are in red. Regards and hope this information is helpful to you. More to follow.

Update: 28 July 2012: Thanks for your kind comments people but this is certainly not my best patchbay example. I'm glad that some of my comments have been interesting though and am drafting some more ideas along with contacting other ex SSL guys to verify what I write beforehand.

« Last Edit: September 12, 2012, 11:42:32 AM by mata_haze »

Matt Sartori

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Re: SSL patch wiring pictures, parts used and techniques. Part 1
« Reply #1 on: July 26, 2012, 09:55:58 PM »
thank you for this.

work of art...


Doctor Ferg

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Re: SSL patch wiring pictures, parts used and techniques. Part 1
« Reply #2 on: July 27, 2012, 10:35:09 PM »
Really interesting stuff Jim, and gorgeous work!!


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Re: SSL patch wiring pictures, parts used and techniques. Part 1
« Reply #3 on: August 14, 2012, 10:06:00 AM »
Bloody hell that's just insanely tidy!

Way better than mata_haze work :)


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Re: SSL patchbay wiring: Parts used and techniques.
« Reply #4 on: September 12, 2012, 10:45:33 AM »
ABSOLUTELY  INSANE !!! Thanks for the post Jim,can't wait until part 2.
I've learned alot from this.

OOPS!! Update , I found part 2...

« Last Edit: September 12, 2012, 10:47:32 AM by Subhumanrecords »
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Re: SSL patchbay wiring: Parts used and techniques Part 1
« Reply #5 on: December 08, 2015, 02:12:13 PM »
Hi Jim,

I'm really impressed by this kind of artwork of yours.
Don't know how someone with only some knowledge could be so precise.

Well, I am about to rewire a SSL patchbay (96 bantam jacks in 2 rows) that was used as a 'user option' patchbay.
So I am not sure which jacks are normalled and the way they were normalled (if they are).
Since the labels are still there, some are obvious (or at least easily guessable but cause an expectation), others 'look like' unnormalled.
I depinned the Varicons (56-pin) already and the crimps are still at the cable - actually I'd like to reuse the cables with the crimped connectors if possible to save me from buying and crimping (or soldering) new pins to the cables. 

So my question is :
how would you start such a 'project' ?
Since I can't see the normalling wires, I was wondering what the single steps are to build a patchbay from ground up.
Do you wire the jacks when they're still outside the patchbay - would I have to remove the jacks from the patchbay to see if they're normalled or not, wire them and then put them back into the front panel ?
Also, in one of your posts, you say that you will give a closer look how to use the lacing twin or cords.
I always wondered, why it is done that way but as you described in other posts, it's better not to use cable ties for several reasons.
Hope this drawing will make it to this forum :-)

Thanks in advance


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Re: SSL patchbay wiring: Parts used and techniques Part 1
« Reply #6 on: December 09, 2015, 01:10:16 PM »
Hi Jim,

Very nice and great post
Waiting part 2 ...