I'll be making some audio short run (1M or less) cables with 3.5MM plugs on one side, and Right angle 1/4" phone plugs on the other. I can do this with off the shelf cables and adapters, but I've tentatively decided I could do a better job making them myself. I'm basically looking for tips on building in reasonably good strain relief at the plugs. I understand about good solder techniques and such, but what else?
For example, would you use heat shrink over the inner area and extend out a few inches? How many layers? Fill the shells with epoxy or shoe goo
? What about a final larger heatshrink tube that covered both cable and part of the plug? Or would that end up looking like total crap? That cosmetic part matters if I ever sell these.
FYI, these cables will be used for "insert" cables on a pedal board, as part of a wireless looper I've designed. They are not expected to take the kind of abuse a typical guitar or Mic cord would need to endure because once placed, the probably won't move often. But I still want them to be durable, and not have inner conductors break loose just from trying different patch setups.
For reference ( nothing written in stone here), the 3.5MM plug ends will likely be switchcraft 568-NYS231L, (Switchcraft : 35HD Series Straight Plugs) , The 1/4" rt-angle plugs will probably those old fashioned types like these at parts express (http://www.parts-express.com/parts-express-1-4-mono-right-angle-phone-plug-metal--090-308), because they are very flat and take up little space between pedals. For the cable, I'll strongly considering this dual coax, From CPC Farnell ( CABLE AUDIO 2 CORE SCREENED BLACK 100M - PP0026 - PRO POWER). Its thin enough to allow a reasonable stack of them to be neatly folded up, and its specs are certainly adequate for short runs of high-Z audio, in the low to mid "line level" signal range.
Sorry for my usual long winded questions, but anything about making durable cables seems like a good topic for this forum. Especially with so much hype and outright unscientific BS that passes for "information" when you look at sale literature on cable products.
For example, would you use heat shrink over the inner area and extend out a few inches? How many layers? Fill the shells with epoxy or shoe goo
? What about a final larger heatshrink tube that covered both cable and part of the plug? Or would that end up looking like total crap? That cosmetic part matters if I ever sell these. FYI, these cables will be used for "insert" cables on a pedal board, as part of a wireless looper I've designed. They are not expected to take the kind of abuse a typical guitar or Mic cord would need to endure because once placed, the probably won't move often. But I still want them to be durable, and not have inner conductors break loose just from trying different patch setups.
For reference ( nothing written in stone here), the 3.5MM plug ends will likely be switchcraft 568-NYS231L, (Switchcraft : 35HD Series Straight Plugs) , The 1/4" rt-angle plugs will probably those old fashioned types like these at parts express (http://www.parts-express.com/parts-express-1-4-mono-right-angle-phone-plug-metal--090-308), because they are very flat and take up little space between pedals. For the cable, I'll strongly considering this dual coax, From CPC Farnell ( CABLE AUDIO 2 CORE SCREENED BLACK 100M - PP0026 - PRO POWER). Its thin enough to allow a reasonable stack of them to be neatly folded up, and its specs are certainly adequate for short runs of high-Z audio, in the low to mid "line level" signal range.
Sorry for my usual long winded questions, but anything about making durable cables seems like a good topic for this forum. Especially with so much hype and outright unscientific BS that passes for "information" when you look at sale literature on cable products.
Cable strain relief is a difficult one, which many get wrong. Most 'strain relief' additions to connectors simply move the strain along the cable a little, so the cable breaks at the end of the 'strain relief' instead of where it enters the connector proper.
The basic idea is to increase the radius of bending of the cable. This means that the strain relief must have the right degree of stiffness: too stiff and it merely moves the strain, too floppy and it does nothing at all.
I suggest experimentation, as it depends on your cable. I have had some success with adding an inch or so of insulation from a slightly thicker cable, which just passes over the cable as a tight fit. Heatshrink might work, but I haven't tried it.
The basic idea is to increase the radius of bending of the cable. This means that the strain relief must have the right degree of stiffness: too stiff and it merely moves the strain, too floppy and it does nothing at all.
I suggest experimentation, as it depends on your cable. I have had some success with adding an inch or so of insulation from a slightly thicker cable, which just passes over the cable as a tight fit. Heatshrink might work, but I haven't tried it.
Copper work hardens.
Soft copper can be bent more than a few times without fatigue cracking.
Hard drawn copper will crack after a few bendings.
You try to avoid tight bends relative to the thickness to avoid the work hardening.
That's what your strain relief is doing.
Alternatively you use thin wires so that the bend to thickness ratio stays high.
Insulation helps avoid tight bends.
Soft copper can be bent more than a few times without fatigue cracking.
Hard drawn copper will crack after a few bendings.
You try to avoid tight bends relative to the thickness to avoid the work hardening.
That's what your strain relief is doing.
Alternatively you use thin wires so that the bend to thickness ratio stays high.
Insulation helps avoid tight bends.
I often fit a couple of inches of heat shrink, sometimes several layers but have also, as DF96 suggests, used a short piece of outer insulation from a thicker cable. It depends on cable thickness and the type/size of plug entry. Neutrik RCA plugs have an inbuilt plastic collet which grips the cable sleeve tightly, they are also sensibly priced. NYS373-0 | Black Straight Male RCA Plug, Gold Plate 1A | Neutrik
Thanks. Good tip there from DF96 about inadvertently moving the strain point. Some added insulation from thicker cable is a good idea too. I am a little disappointed that more products specifically for this don't seem to exist.
Since I'll be getting my cable from this UK company anyway, what do all of you think of this kind of connector, with the built in springs for strain relief? I'd imagine it would depend on how snug a fit you could get.
PSG02539 - PRO SIGNAL - 3.5MM JACK PLUG, STEREO, METAL | CPC
Part of the issue of strain relief is bending, but the other part is being immune to pulling. Thats why i was wondering about filling the inside cavity of the shell with some kind of flexible epoxy, if such a thing exists.
Since I'll be getting my cable from this UK company anyway, what do all of you think of this kind of connector, with the built in springs for strain relief? I'd imagine it would depend on how snug a fit you could get.
PSG02539 - PRO SIGNAL - 3.5MM JACK PLUG, STEREO, METAL | CPC
Part of the issue of strain relief is bending, but the other part is being immune to pulling. Thats why i was wondering about filling the inside cavity of the shell with some kind of flexible epoxy, if such a thing exists.
These require different arrangements. Protection from bending needs a softish strain relief through which the cable can move a little. Protection from pulling means a stiff strain relief which grips the cable very tightly. If you need both then you need to do both: clamp the cable, then add strain relief after that.Peter Pan said:
I had trouble in the past finding a 3.5mm jack plug which can take a decent diameter cable. I eventually used these - Switchcraft 35HDBAU Gold 3.5mm Stereo Mini Jack Plug
I'm sure i didn't pay that much for them though, you could probably find them somewhere else cheaper.
I replaced the clear plastic sleeve with a length of heat shrink tubing which when fitted gripped the cable and protruded out from the plug by an inch or so. This worked very well for me.
I'm sure i didn't pay that much for them though, you could probably find them somewhere else cheaper.
I replaced the clear plastic sleeve with a length of heat shrink tubing which when fitted gripped the cable and protruded out from the plug by an inch or so. This worked very well for me.
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