Author Topic: How to wire a 24 circuit DL plug (Jim L method)  (Read 11091 times)

jimlfixit

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How to wire a 24 circuit DL plug (Jim L method)
« on: March 11, 2013, 03:13:00 AM »
I thought it may be an idea to show how I wire a DL plug connector in case it helps anyone who hasn't done one before. This example is a 24 pair Van Damme cable wired to a typical 24 circuit DL channel connector as used for mics and multitrack connections as well as most user option DL's. This is just my method but see my comments at the end (if you can stay awake long enough).

Tools required: From top left and clockwise:

1   Hellerman rubber sleeve expanders. I use rubber sleeves rather than heatshrink so that is why this is included. Lubricating oil is also required (not shown).
2   Lacing twine (as used by SSL on their internal patchbay looms) I use this to secure the sheathing and separate the 3 batches of 8 wires for the DL.
3   Cable strippers (Stripmaster in this case). Notice the long spacer used with tape to measure the length of strip.
4   Core wire strippers. I have several versions but these cheap ones can strip both hot and cold wires at the same time.
5   Jewellers screwdriver used to push home various loaded crimps if required.
6   DL crimpers. These are ITT versions with a metal block to a hold the crimp.



1   I don't know anyone who does this but I strip the multicore insulation back 200mm and put some cable sheathing on. This is for three reasons:

1   It gives the loom more flexibility especially if the loom exits the DL at an angle (as used on patch panels rather than just hanging down from an SSL connector panel).
2   It allows the individual circuits to be orientated to suit their load positions within the DL (see picture in point 11).
3   Most importantly, this extra length allows you to properly strip and deal with the individual cables without having up to 32 circuits fanning out over a short 90mm length. This picture shows a length of SSL multicore unlike the Van Damme used in the rest of this post.



2   Tape the ends so that you can add suitable heatshrink and 175mm of 20mm sheathing. This is shown in its final place but move it up and over the multicore insulation to keep it out of the way so you can work on the 24 wires with about 200mm of access length. The masking tape label is only temporary by the way!



3   Separate the loom into lots of 8 circuits. I normally tie each batch of 8 together so I know which circuits they are. This also helps while you load the connector and saves you having to deal with 24 wires at once. The green ties were only used as I couldn't find my lacing twine in time!


4   Stagger the batches of 8 circuits into the DL. I normally stagger each batch of 8 circuits by cutting them to different lengths. 1-8 is the longest and 25-32 is the shortest. These differ in lengths by about 8mm. I leave 1-8 as 200mm, cut 9-16 down by 8mm, the 17-24 circuits (which are the other side of the centre section spindle) by 16mm and 25-32 by another 8 mm. By the way, I'm not advertising Snap On cutters here, I have had these since 1981 and they are still just about up to cutting a few cables at once!


5   I stripped the balanced circuit wires with the red Stripmaster strippers using the spacer with tape marking to get the required length. Notice that I left the insulation on the cables. You can now see the DL plug with the staggered batches of 8 in line with it.


6   Sleeve the circuits with heatshrink or sleeves ... your choice and another subject (both rubber sleeving and heatshrink have their good and bad points). This picture is actually for a different cable (3 x 12 pairs into one DL ...a separate subject) but shows the sleeving involved.


7   Once the insulation and drain wires are sleeved, I tend to crimp the drain wires first although this is not essential. By doing them now it gives an idea of how far back to strip the core wires (hot and cold) so that they are in line with the screened wire and also stops them fraying out while you deal with the core wires. I don't crimp the rear part of the drain wire with the sleeve as it would be too big (unless you use very small heatshrink) and may present problems when inserting or removing in/out of the DL. When you crimp these drain wires, you will have to twist them tightly first and chop off any excess. Notice I have now secured each batch of 8 wires with lacing twine.



8   I used the small black strippers to strip the hot and cold wires in one go. Again, twist them after stripping and end up with about 3mm so that they fit into the crimp with the rear part of the crimp holding the wire insulation unlike the screen (see point above).

Inspect and tug all the wires. This is important and I have a careful look in case the conductive part of the wire is not making proper contact with the crimp. If not, it may be able to be removed or, failing that, you could possible carefully solder the crimp and test it out from the other end. If your eyesight is not too good, use a magnifying glass.

I tug the wires by grabbing hold of the crimp and tugging it a few times. With the proper crimp tool used there should not be a problem but if it is faulty or you have only partly crimped the wire, it may come loose. This picture shows the wires after tugging hence not being straight (Stop it ... I'm not saying they are gay ... and no more thoughts about tugging either!).


9   Inserting the crimps. Bear in mind the retention flap on the pins needs to be the correct way round for both plugs and (chassis) sockets. On plugs, the flap is facing outwards away from the centre spindle on both sides (cct 1-16 and 17-32) and on sockets, they face towards the centre.

Start from the bottom near the cable exit to load the wires. Insert cct 17-24 (or 25-32 if loading the whole DL) and bear in mind the retention flap is facing the correct way. Also, have a careful look at the connector labelling to make sure you don't load it upside down. I did this recently and I should know better after 32 years but the writing on the DL's has got smaller over the last few decades.


Close up picture of 17-24 loaded.


10   Insert cct 9-16. You now have 17-24 fitted so 9-16 just get loaded above them and keeps the view clear. These are somewhat more difficult though as they are scattered around the centre area. Be careful.


11    Insert cct 1-8. These should be easy to load as they are in a row without the more complex loading around the centre area plus you are at the end of loading a DL and should be more relaxed by now!   

In point 1.2, I mentioned that the wires could have a chance to be orientated properly. You can see from this picture that some wires cross over each other to get into the right place!

Looks like I have cut off the lacing twine! Perhaps that is because it keeps the budge near the multicore insulation fairly small and the connector has already been loaded so, no need to keep them separated.

Close up picture of the 24 circuits fully loaded. Nearly there!


12     The black sheathing was resting further back on the cable insulation up to this point to keep it out of the way whilst I dealt with the 24 circuits (see point 2). Now, move it into place onto the 24 wires as shown.


13   I now secure the sheathing into the DL with lacing twine and then apply tape over it. Orientate the loom to exit the backshell out of the rear or at a right angle. I don't use heatshrink at the DL end because:

1   There is no need in my view.
2   It makes servicing hard to deal with.
3   Most console installations are a one off fit lasting 5-10 years or so therefore, once fitted, most DL's will probably not be tampered with for years.

14   Secure backshell lightly by fitting two screws. Unscrew the cable clamp and fit the backshell making sure that the loom is pushed into it a bit to allow some slack within the shell. The rear clamp takes the strain.


15    Fit the handle and covering plate. Test the whole loom if possible and only then:
1   Fit the last two screws
2   Secure the sheathing at the multicore end and tape if required.
3   Apply a heatgun to the heatshrink at the multicore end.

Bear in mind that you may need to take the DL apart to some extent if there is a fault (hence my suggestions above).


I hope this proves useful as it has taken many hours to finally present this post (nearly 50 pictures, photobucket uploads, draft forum posts etc). This is just my method of constructing a 24 circuit DL plug and I realise that everyone has their own opinions. Hardly anyone uses the black sheathing shown and most people use heatshrink these days it seems. I would argue that rubber sleeving for individual circuits is better but that debate can wait. My methods are based on practical experience over 30 years especially if confronted with a quick fix repair after a wiring company has permanently heatshrunk everything in sight and doesn't have to deal with the consequences!

Must go and get some din dins (or an early breakfast) as it is 3 am. More lengthy wiring posts from me fairly soon when I recover from this one!

Finally, I attach a blank DL plug wiring layout for your own use.

Regards from Jim Lassen (www.profcon.co.uk). Also on Facebook FACEBOOK
« Last Edit: March 11, 2013, 01:17:59 PM by jimlfixit »

marcmozart

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #1 on: March 11, 2013, 06:42:32 AM »
Hall of Fame-Post!!! I just wired my first (prototype)-DL yesterday and 12 hours later here are all the answers to yesterdays questions...  :)
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sintech

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #2 on: March 11, 2013, 09:45:30 AM »
Jim, it's pure art to my eye, thanks for sharing.

marcmozart

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #3 on: March 16, 2013, 09:06:05 PM »
Jim,
thanks again - here's proof I'm officially using the Jim L-method. Still on a learning curve though, but my first 24 circuit D-Sub to DL plug is actually working beautifully and already delivering sound into my G-Series!
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jimlfixit

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Reply to Marc M about "How to wire a 24 circuit DL plug (Jim L method)"
« Reply #4 on: March 16, 2013, 09:49:09 PM »
Hi Marc. Thanks for replying. I saw your picture and wondered what cable are you using? It is a standard type colour code judging from the colours but I can't be sure what make it is. What type of strippers are you using for this? Did you see the red Stripmaster version I showed in my DL post?

Be careful stripping the black insulation off the balanced circuits as it looks like you may be in danger of accidentally cutting into the core wires. Also, why have about a 40mm length of heatshrink on there? Surely, you only need enough to cover the circuit and core wires plus screen. Maybe 20 or 25 should be enough.

Heatshrink is okay but less flexible than rubber sleeving especially if used in a small area like a DL connector although it has a smaller diameter. I have mentioned advantages and disadvantages for both in one of my wiring posts about patchbays I think.

I'm about to wire some DL's to PT 25 way D connectors so, will take pictures, document and post something in the wiring menu soon.

Hope this helps for now and regards from Jim Lassen (www.profcon.co.uk).Also on FACEBOOK

marcmozart

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Hi Jim,
this is the cable I'm using... perhaps you can comment on the specs?
http://www.thomann.de/gb/cordial_cms_24_studiocore.htm

I bought these four years ago (before we met), otherwise I would have checked back with you. I had soldered Sub-D's on one end, and XLRs one the other end (for my previous non-console setup). Knowing the console install would come (one day), I made these multicores 7-8 meters long and now cut them in half, and adding DLs.

The wire stripper I have looks similar to the one you use (picture below) - it was 7 Euros at "Praktiker" (german DIY warehouse). I was indeed in danger of cutting into the core wires, and I later found out that by stripping two cables at once it would not do this. I'm also posting a pic of my DL crimper. Luckily, I bought it for very little money on ebay from David Kulka (L.A. tech guru aka http://www.studioelectronics.biz).

I have the check out the rubber sleeving when I get a chance.

Hi Marc. Thanks for replying. I saw your picture and wondered what cable are you using? It is a standard type colour code judging from the colours but I can't be sure what make it is. What type of strippers are you using for this? Did you see the red Stripmaster version I showed in my DL post?

Be careful stripping the black insulation off the balanced circuits as it looks like you may be in danger of accidentally cutting into the core wires. Also, why have about a 40mm length of heatshrink on there? Surely, you only need enough to cover the circuit and core wires plus screen. Maybe 20 or 25 should be enough.

Heatshrink is okay but less flexible than rubber sleeving especially if used in a small area like a DL connector although it has a smaller diameter. I have mentioned advantages and disadvantages for both in one of my wiring posts about patchbays I think.

I'm about to wire some DL's to PT 25 way D connectors so, will take pictures, document and post something in the wiring menu soon.

Hope this helps for now and regards from Jim Lassen (www.profcon.co.uk).Also on FACEBOOK
« Last Edit: March 16, 2013, 10:49:06 PM by marcmozart »
1992 SSL 4048 G-Series
Mix Engineer Blog
http://www.mixedbymarcmozart.com

Artur D'Assumpção

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #6 on: March 17, 2013, 01:44:30 PM »
Awesome post Jim! Thank you so much for the info!

With this community SSL legacy will indeed endure for much more years! :D

madmuso

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #7 on: March 29, 2013, 11:24:42 AM »
Killer work Jim!

I have a question regarding the ground/shield on DL's.

Does it matter if the ground line from one channel touches the ground line of another channel? The reason I ask is because we have some XLR to DL looms here, and some of the grounds have been stripped back too far and they sometimes touch depending on which way the cable is resting on the ground, etc.

thanks, and once again, awesome work. You've certainly got patience and skill!

kilmister

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #8 on: March 29, 2013, 12:27:42 PM »
Yes it does. If shields are touching eachothers you destroy star grounding scheme. It's very advisable to use heatshrinks over shield conductors.

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jimlfixit

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DL wiring tools and touching screens
« Reply #9 on: March 29, 2013, 10:13:08 PM »
First of all, thanks to everyone for commenting on my "how to wire a DL plug" post. I wish other people would post their own version so I can learn other methods as well. I use the black plastic sheathing to give the loom more flexibility and mainly for ease of wiring as it gives you about 200mm to play with (rather than about 100) when you are trying to strip, sleeve and crimp 24 to 32 balanced circuits.

I am going to elaborate on my initial DL plug wiring post soon with some more detailed comments which should make the job easier after I explain them.

To address a few points raised in the last few replies:

Marc: I don't know about that Thomann cable but it seems very cheap looking at their website. I just hope it sounds good! Most wire strippers which don't cut through the individual core wires (like 7x0.2mm) are okay and the DL tool you show is fine for a few installations. The problem with the white nylon part is that it will wear out in time but, for a studio owner undertaking a few installations, it should be fine. It's only us wiring people who do this stuff a lot who have to be aware of tools wearing out after prolonged use and buy better ones to begin with (ones with metal inserts instead for instance). I have some of those DL crimpers you showed in your post available if anyone needs them.

Madmuso: Kilmister answered your question although I would (probably wrongly) suggest that it may not matter that much if they are the same type of signal function like all mic sources or all record inputs to multitrack in terms of signal grounding. Any grounds touching especially with different signal types is not advisable though and highlights bad wiring techniques. In fact, show a picture of your exposed shields so we can comment on it. Seems like your loom was not the best in the world and certainly not really good enough for a Pro studio!

A few decades ago, foil screen cable (not jacketted) was commonly used like Alpha, Belden and Klotz as examples. Some people did not screen the exposed foil screening and it shorted between circuits. I applied 3.2mm heatshrink to act as a jacket to stop this happening.

I am baffled why some people still don't sleeve (heatshrink or rubber sleeve) the ends of balanced circuits even though the drain wire may be sleeved. A bit more attention and time with the wiring will save a lot of headaches later on. People spend money on equipment and the wiring budget is hardly anything but it is important to get it right. If some wiring is that unreliable that it may or may not work whilst resting on the ground, it really needs to be rewired surely?

Studio owners, engineers and even some techs are not necessarily great wiring people (I'll get some hate mail after this!) and naturally want to get all that expensive gear up and running BUT, attention does need to be paid to all that string (cabling) connected between the equipment.

That is why I am posting various wiring topics on this site to lend my 32 years worth of experience to you SSL fanatics. I am still learning, trying to improve my techniques and get faster and more efficient even now! Hope this helps in some way.

I've recently completed some 25 way D ProTools wiring to DL's so will post a new topic on this soon when I've downloaded some pictures via Photobucket and got the writing sorted out.

Regards from Jim Lassen (www.profcon.co.uk). Also on Facebook FACEBOOK




« Last Edit: March 29, 2013, 10:33:45 PM by jimlfixit »

madmuso

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #10 on: March 30, 2013, 12:01:26 AM »
Thanks for the replies guys.

The owner of the studio consulted someone on the correct DL wiring method a long time ago, this was before I became involved in helping him out. It wasnt until the other day that I noticed the grounds exposed and asked him if thats how they should be. He told me that the guy he consulted said it was fine, sounds like he has been misinformed. I may have to break the news to him that he has to heat shrink them. And now that I have seen your pics Jim, his DL's dont have backshells either, is this a must?

jimlfixit

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Exposed screens and DL backshells
« Reply #11 on: March 30, 2013, 12:36:14 PM »
Hi Madmuso

I would like to see a picture of the exposed screens on your DL to XLR lead so I, or others can comment. The method you describe is certainly not good plus there isn't a backshell fitted!

I've seen lots of consoles which do not have backshells on the DL's but, the rear clamp takes the strain off the cables and you may have 32 circuits (96 crimps) just hanging down out of the connector. I sell machined backshells for about £9 so it is probably worth that for the extra protection it brings. Also, I think some people who wire DL's can't be bothered to contain all the individual splits within the backshell shell but, as I have shown in my original post on wiring DL's, it can be done with a bit of careful preparation.

As for handles, you could save money (about £2-3) by not having these as normally, once a DL is connected to the console panel socket connector, it probably stays there until you eventually change the console (for another SSL of course!).

The DL plug spindle can be turned by a larger flat blade screwdriver which does the same job as a handle so, I would suggest, buy some backshells but perhaps you could save money by not having a handle (I've probably talked myself out of some sales here!!!).

By the way, if you do have a handle, it may be worthwhile filing in down a bit so it doesn't scrape on the backshell rear cover (some of you may have found it difficult to turn and that is why).

Hope this helps clarify things a bit and make sure that naughty wire person improves his or her wiring standards!

Regards from Jim Lassen (www.profcon.co.uk). Also on FACEBOOK

madmuso

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Re: How to wire a 24 circuit DL plug (Jim L method)
« Reply #12 on: March 31, 2013, 04:31:34 AM »
I will upload once I take pics. He does have the handles on them which you turn and locks them in tight, just not the backshell casing.

Also, I caught up with the studio owner last night and mentioned about that exposed grounds and described your pics.
He said to me "is his name Jim", I said "yes, do you know him?" He then told me that not too long ago he purchased some patchbays for the console from you! Small world. His name is Ben, obviously from Melbourne, Aus.

jimlfixit

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Wiring a DL (Jim L method revised)
« Reply #13 on: April 05, 2017, 02:41:57 AM »
Hi all, even though I have been wiring countless DL's for decades now, I still keep tweaking them a bit and learning from the last ones!
I will do another lengthy updated post shortly but, for now, I leave 1-8 as 200mm, cut 9-16 as 190mm and have revised circuits 17-24 to 170mm.
This way, it keeps a lot of the sleeving away from the centre spindle as shown in the picture below.
More on this soon and I am preparing some notes and pictures on how to wire a DL to DAW 25 way D loom which I will post as another topic.