Dumbass question

[edwinhurwitz]

OK, my soldering skills aren't terrible (I built 6 7th circle pres which all worked right out of the gate and have made tons of mic cables, snakes, etc), but I feel like I'm missing something. I have two XLR patchbays and no matter how carefully I solder and make sure everything is really well put together, inevitably, some of the connections come apart. What can I do to make it so these connections just don't come apart? Is there some trick I'm missing? The back of the patchbay is open and the cables do get moved around a lot.

I'm using guitar cables and mic cables I made in the early 90s that have never given me trouble, so I know it's not my basic soldering skills that are at fault.

TIA
Edwin

[ToddF]

Are you tinning appropriate parts?
Todd

[tuckpunk]

My guess:
Is it lack of strain relief?

Are you mechanically tying down the cable, near the solder points, so that when the rest of the cable moves....the cable doesn't move at the solder joint?

Oh and.....

Are you tinning appropriate parts?

Tinning inappropriate parts would hurt and possibly be detrimental to one's reproducibility. :)

[Rick Sutton]

I'm with Tuckpunk. With good soldering technique and proper strain relief your connections should last forever.

[edwinhurwitz]

Thanks for the replies! The key here has got to be strain relief. There isn't really any place to tie anything down. The panel I'm using is the one from Redco.com. (Redco Audio). I know that my solder joints are fine, as I have cables that have lasted for years. They certainly outlast commercial cables.

So, to what can I tie them down? How do I do strain relief?

Edwin
My appropriate parts are tinned and my inappropriate parts are......

[the scum]

So why do the connections break?

If the solder job is poor, then of course, cold joints fall apart. But you say you've soldered before, so that may not be it.

If the joints are good, where is it breaking?

Are you nicking the copper when you strip it, so that with a little stress, the copper breaks? You might need a better stripper. They make thermal ones that melt the insulation, rather than slice it,which avoids damaging the copper.

As for adding strain relief, any hardware store will have these little self-adhesive cleats that you can run a zip tie through. Stick a few down, and use zip-ties to tie the cables so there's a little slack back to the solder joints.

[Yago]

I think all points are really covered , I would just add/reiterate a few things :

Are you tinning the wires first ?
Are the joints shiney or dull ?
It is often better to leave the cores a little too long and let the screen take the brunt of meachanical load ( if screen is substantial)
If there is insufficient strain relief , try useing glue filled heat shrink tubing .

[edwinhurwitz]

Originally Posted by Yago

I think all points are really covered , I would just add/reiterate a few things :

Are you tinning the wires first ?
Are the joints shiney or dull ?
It is often better to leave the cores a little too long and let the screen take the brunt of meachanical load ( if screen is substantial)
If there is insufficient strain relief , try useing glue filled heat shrink tubing .

Yes, I am tinning the wires.
Yes. the joints are shiny.
If by screen, you mean the shielding, it's not really going to work, because the Mogami cable I'm using doesn't have very strong shielding and it has a drain wire that is the same size as the other signal carrying wires. I am using Mogami 2931 and 2932 snake cable.

There has been no real strain relief. What I have done is cut the individual channel cables to varying lengths so that the main part of the cable runs parallel to the rack panel. This seems to help a little, but glue filled heat shrink might be the way. What I really need to do is to somehow cable tie the whole thing to something that supports the snake cable and takes the stress off the solder joints.

Another thing I am trying is to put the patch bays at the bottom of the rack rather than the top so that the cable sits on the bottom of the rack rather than just hanging. I think that's a good first step.

Edwin

[Rick Sutton]

As far as strain reliefs I keep several types in my parts supplies. If you don't have have a local source get a catalog from Mouser, Digikey or similar and stock up on the ones you are likely to use. I prefer ones that are secured by screws but the adhesive ones are useful. Stand-offs for elevating the strain reliefs are also very useful. Obviously, you'll need loads of cable ties to secure cables together and to the ties.

Just noticed your post from above and you are using Mogami 2931 and 2932 snake cable. That's what I use and it is actually one of the best as it is reletively light weight and very easy to strain relieve. Get the loop type reliefs that fit snugly around the snake and SCREW those to something solid. The snakecan easily hang on that and the individual lines can be bundled with cable ties and relieved by the many devices that use a cable tie as a connection. A good battery drill (makita) is your friend here as you need to secure this stuff properly.
The goal is to have each connection "floating" mechanically with only the weight of the last inch or two of the cable bearing on the connector. With the Mogami you are using that is a very small weight.

[edwinhurwitz]

Originally Posted by Rick Sutton

As far as strain reliefs I keep several types in my parts supplies. If you don't have have a local source get a catalog from Mouser, Digikey or similar and stock up on the ones you are likely to use. I prefer ones that are secured by screws but the adhesive ones are useful. Stand-offs for elevating the strain reliefs are also very useful. Obviously, you'll need loads of cable ties to secure cables together and to the ties.

Just noticed your post from above and you are using Mogami 2931 and 2932 snake cable. That's what I use and it is actually one of the best as it is reletively light weight and very easy to strain relieve. Get the loop type reliefs that fit snugly around the snake and SCREW those to something solid. The snakecan easily hang on that and the individual lines can be bundled with cable ties and relieved by the many devices that use a cable tie as a connection. A good battery drill (makita) is your friend here as you need to secure this stuff properly.
The goal is to have each connection "floating" mechanically with only the weight of the last inch or two of the cable bearing on the connector. With the Mogami you are using that is a very small weight.

Thanks, Rick! This is exactly what I needed to know! I guess my last question is would these strain reliefs be attached to the rack panel or to the rack itself? I don't really want to drill into the rack (gotta love those Makita cordlesses!). It's kind of too bad there aren't strain relief mount points built into the rack panel.

Thanks, guys! Everyone's posts have been very helpful.

Edwin

[Rick Sutton]

Originally Posted by edwinhurwitz

I guess my last question is would these strain reliefs be attached to the rack panel or to the rack itself?

Actually anywhere they are needed. If done cleanly the only thing showing from the outside is a screw head. I've used all kinds of methods for strain reliefs including the round romex box electrical reliefs, and I'll often fashion any metal brackets that are around into a platform to attach multiple reliefs inside or at the back of a rack. A little Krylon black spray paint and it looks fine. Remember when drilling on panels and in racks to catch all the drill bit filings and to de-burr the hole.
On rack panels there often isn't enough space to fit a strain relief so I use a "stand off" post with threaded ends to extend the nylon relief to be at the right depth to make the wiring loom hang directly behind the connectors. Lock washers and Locktite solution is handy here when all your weight is attached by just the one screw between panel and post.
Another useful method in a rack is to install a rod or bar that is attached at both sides of the rack and runs parallel to the back of your connectors. The snake can be tied along the bar with the individual lines exiting at the appropriate location. This type of relief can be placed several places up and down the rack and carry quite a lot of cabling.
Jeez, I'm just full of trivial info today......if you are concerned (like me) about the aesthetics of holes in your racks always measure and mark your holes before drilling. Accurate, consistent placement is the obvious difference in looks between a pro and amatuer installation. Nothing like seeing a bunch of holes in a piece of gear with even the slightest variation in placement. The eye picks up on this immediately.

[Rick Sutton]

Here's a picture I found on the net of the horizontal bar strain relief.

[edwinhurwitz]

That looks exactly like what I need. I think I'll have to improvise it as I don't really see patch panels like I have set up with them from the get go.

Edwin