quick question from the back of the room

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cressy
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#1 quick question from the back of the room

Post by cressy »

when using cat 5 or cat 6 as a speaker cable does one just use a couple of cores together for the live and a couple of cores for the neutral?
cheers ant
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pre65
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#2

Post by pre65 »

Hi Ant.

That's what I would do. :wink:

I used to do 4 colours on one and 4 plains on the other, but Mike H reckons 2 pairs on each is better. I shall be doing 2 pairs on my next set.
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#3

Post by cressy »

cheers phil
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Mike H
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#4

Post by Mike H »

That's what I ended up doing.

Tried it using each pair as both live & return (x 4 in parallel) and it just sounded weird.

So ended up 2 twisted pairs as live, other 2 twisted pairs as return.

Also, each pair has a different pitch of the twist, in other words the length of each 'turn' of the twist, if you see what I mean, so I figured would be best to use the two shortest for one direction (e.g 'live' side) and the two longest for the other (e.g. 'return' side).

Hope that makes sense.

NB: cat6 has the white 'X' section plastic divider down the middle to separate the pairs.
 
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#5

Post by Lynn Olson »

If all the whites are ground, and all the colors are hot, that maximizes the capacitance of the cable. Transistor amps won't like that ... some will even blow up if they see a load of thousands of pF. Valve amps (the kind with feedback) won't be too thrilled either.

Using two twisted-pairs as ground, and the other two as hot, drops the load capacitance many times, to a value comparable to generic wire pairs. Amps are happier.
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#6

Post by Nick »

But conversely, the high capacitance layout works well in the "twisted twin" loudspeaker cable (just not as Linn says with Naim amps).
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#7

Post by Scottmoose »

From a design perspective I'm with Lynn here -highly capacitive speaker wire seems to me to be looking for trouble. With that said, I also acknowledge that I haven't heard the twisted twin configured wires cause any problems in the systems that have been using it, so as usual, appears to vary with circumstance etc.

Alternatively, don't use Cat5 at all. ;) Ring mains cable, either run parallel or with a very light twist (say, 1 turn per foot) does a pretty decent job for budget wire, assuming the gauge is sufficient to hold voltage drop to reasonable levels for your app.

Of course, being the tone-deaf monster around here, I'm generally quite happy with perfectly ordinary OFC copper zip wire or extension leads with the ends lopped off. Although oddly enough, I'm actually quite interested in the subject of speaker wire & occasionally wile away a spare moment thinking up 'new' types... my current (sorry) one uses four runs of zip wire laid out in parallel, the left hand four conductors acting as the hot lead, the right hand four the return. Nice low capacitance. If inductance is a bit high for the system, you can alternate the conductors for each leg. I'm not recommending either though. Just me mooching around.
Last edited by Scottmoose on Thu Jan 30, 2014 9:04 am, edited 2 times in total.
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andrew Ivimey
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#8

Post by andrew Ivimey »

how we do love speaker cable!
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Paul Barker
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#9

Post by Paul Barker »

Scott can you put up an image of zip wire please? I don't know what it is and Google showed me someone traversing along a wire.
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#10

Post by Scottmoose »

Sorry about that Paul, it's just another term for ordinary shotgun / figure 8 two-conductor speaker wire e.g. this stuff. I suspect it's more commonly called that Stateside, & just refers to the fact that you can 'unzip' the two conductors by splitting the thin connecting web.
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Paul Barker
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#11

Post by Paul Barker »

Got you. I did pick up somewhere lamp chord, which also sometimes uses this 2 core arrangement, though often twisted.
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