Cat5 as interconnect

[Rochey]

Ptownkid mentioned in another thread that multicolour cable from Cat5 cable could easily be used for connecting various boards in an a project together (i.e. dissasemble the cat 5 into indiviual wires etc. and solder as usual)

I'm not all that sh.hot on the physics of wire etc, so I'm wondering, could this be a cheaper alternative source of cable than buying indiviual colours by the reel?

Is there anything specifically 'wrong' with using cat5 individual wires for connecting pots to pcb's etc?

cheers

R

 

[Brian Roth]

Solid core vs stranded comes to mind....

Bri

 

[gyraf]

I've had very good results using solid-core cat.5 cable for internal wireing..

Jakob E.

 

[amorris]

this is interesting, I found it on the web:

Category 1/2/3/4/5/6 ? a specification for the type of copper wire (most telephone and network wire is copper) and jacks. The number (1, 3, 5, etc) refers to the revision of the specification and in practical terms refers to the number of twists inside the wire (or the quality of connection in a jack).

CAT1 is typically used for telephone wire. This type of wire is not capable of supporting computer network traffic and is not twisted. It is also used by phone companies who provide ISDN, where the wiring between the customer's site and the phone company's network uses CAT 1 cable.

CAT2, CAT3, CAT4, CAT5 and CAT6 are network wire specifications. This type of wire can support computer network and telephone traffic. CAT2 is used mostly for token ring networks, supporting speeds up to 4 Mbps. For higher network speeds (100 Mbps plus) you must use CAT5 wire, but for 10 Mbps CAT3 will suffice. CAT3, CAT4 and CAT5 cable are actually 4 pairs of twisted copper wires and CAT5 has more twists per inch than CAT3 therefore can run at higher speeds and greater lengths. The "twist" effect of each pair in the cables will cause any interference presented/picked up on one cable to be cancelled out by the cable's partner which twists around the initial cable. CAT3 and CAT4 are both used for Token Ring -- the only difference is CAT3 can be as long as 100 meters while CAT4 can only be 200 meters.

CAT6 wire was originally designed to support gigabit Ethernet (although there are standards that will allow gigabit transmission over CAT5 wire, that's CAT 5e). It is similar to CAT5 wire, but contains a physical separator between the four pairs to further reduce electromagnetic interference.

 

[Rochey]

as it's not shielded, i don't think I'll get many problems with capacitance of the cablling, but do you guys see any issues I can't think of?

 

[amorris]

I find that the solid core in small diameters break easy if it is bent out of the way multiple times when prototyping . the stranded flexes better with constant moves. I like it on trace rebulding though. you can snake it along the pcb and it will stay.

 

[featherpillow]

Cat5 is tough to work with, but I love the way it sounds. I use it on every project.

 

[mojotron]

Small diameter solid-core wire is fragile at the connection points, you can only depend on one good bend until it runs into the cable.

I haven't noticed a lot of issues with audio signals, but I have used solid core only on breadboards - where there are already some capacitance issues - I would prefer stranded for the signal path just so that I got the best results from my work. However, something like cat5 would be perfect for replacing power/ground busses that would normally be tough to route/change on a PCB layout - low wattage stuff of course.

 

[PRR]

> The number (1, 3, 5, etc) refers to the revision of the specification and in practical terms refers to the number of twists inside the wire (or the quality of connection in a jack).

All of which is very interesting when the frequency is many-MHz or the line gets near a mile long; but pretty irrelevant for in-the-box hookup wire.

It's just small-gauge wire with a twist. For single runs, un-twist and use. The twist is handy for wire-pairs; the 8-color (CAT5 and up) is handy when you have multiple wires going the same place.

Tighter twist has very little benefit in audio, as long as the interfering source is further away than the length of one twist. And if it is closer, tighter twisting won't stop it from finding a way to get in. It would take some very odd situation for CAT6 to be better than CAT3 for audio.

> as it's not shielded, i don't think I'll get many problems with capacitance of the cablling

All cables have capacitance. The pFd of data-cable is in the specs, but figure 25pFd per foot/ 80pFd per meter of twisted-pair. A single wire in free space has slightly lower pFd, but inside a box it won't be a lot less than the twisted-pair. Coax construction raises capacitance to 30pFd/ft or 100pFd per meter, a small increase.

BTW, you can get shielded ethernet cable. It is way-expensive and rarely stocked: data-dudes rely on twisting and good balancing rather than shielding, and turn to the shielded stuff only when necessary.

CAT3- is normally 4-wire, CAT5+ is 8-wire. That may not matter: CAT3 is not used in new networks and voice usually goes on CAT1 or CAT5 these days.

You can get Regular or Plenum. Plenum costs a lot more. If you expect a fire, and you breathing the smoke, use Plenum. Building codes will require it in certain situations where a wire-fire's smoke might get into the ventilation system and fill the building, but is not needed in most networking, certainly not for audio.

As mojo says: solid is fine for permanent work, use stranded if you expect to poke or shake it a lot. The electrical properties, in the audio band, are identical.

 

[fum]

Another interesting tidbit is that the plenum cable I've seen is stranded.

At least a few years back =)

Regards

ju

 

[Larrchild]

http://www.venhaus1.com/diycatfivecables.html
CAT5 spkr cables

 

[Butterylicious]

Not all plenum rated Cat5 cable is stranded, but you can order it that way. The only real difference between regular Cat5 and plenum rated is the outer jacket of plenum rated takes much longer to ignite, ie it melts vs regular jacket cable which combusts. Plenum rated cable is require where run exposed above ceiling when the return air is an open system.

Continuing to state the obvious, Cat5 insulation is only rated for 40 volts and I don't remember the current capacity of 24 guage wire.

 

[Kev]

[quote author="Larrchild"]http://www.venhaus1.com/diycatfivecables.html
CAT5 spkr cables[/quote]

YEP

I've also seen Ribbon Cable used as speaker cable.
AT insane mark ups
yes well presented gold plated banana plugs and a beautiful presentation case ... but at that price ??
I don't agree with much of the capacitance and inductance discussions.

All these ideas are fine ... when presented to the client as a quality and cost effective solution to the insane prices of the esoteric stuff.

I still maintain that quality multi stranded high copper content power cable stacks up well against all comers.