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Old 14th October 2002, 11:38 PM   #1
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Talking I think I'm ready to start my first DIY project

Well, I have a few more paychecks to wait until I can afford some of the paradigm speakers I want (Studio/40 fronts, Studio/CC center, and Studio/20 for rears) so I thought I would make some speaker wire for them in the waiting time using the CAT 5 method: http://www.venhaus1.com/diycatfivecables.html

The reviews of this method (from the previous link and this forum) seem to be positive. Of course being the skeptic that I am, I have a few questions and concerns.

The site mentions that "While the high capacitance is virtually a non-factor as far as sonics go, it MAY be a problem for unstable amplifiers and cause them to oscillate. This can be mitigated by NOT using very long lengths of cable (>8 ft.), and making sure your amp isn't one of the few that are unstable into high capacitance loads.

The above statement puts two thoughts into my head. Firstly, does/has anyone ran this type of wire from a Pioneer Elite receiver? Currently I'm thinking this is the receiver I'm going to buy: http://www.pioneerelectronics.com/Pi...,71335,00.html I found that receiver for $890 online at brandnamez.com.

Secondly, if I run the CAT 5 speaker cable in short lengths to my left, right, and center channels, what do I do about my sorrounds? I would think it would be best to be consistent throughout the setup but the longer lengths of cable required for sorrounds makes me nervous.

Overall I have to say I have learned a tremendous amount lurking these forums over the past weeks. Lots of great info on everything from why bi-wiring isn't the best thing to making your own interconnects. Thaks a lot again guys.
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Old 15th October 2002, 01:21 AM   #2
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Default Cheap Cable....

12 or 20 pair indoor telephone cable works rather better than Cat-5 - more copper and different insulation.
I would use 12 pair for L/C/R and 6 pair for the rears.
Despite the warnings I have had no amplifiers go wrong with these cables (excepting Naim amps but these are a special case).
Indoor telephone cable is cheap too.
Metal recyclers are a good source for just about free.

Eric.
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Old 15th October 2002, 02:28 PM   #3
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I second mrfeedback on using the indoor phone cable. I've been using it for years and have never had a problem with any of the amplifers I used it with, sounds good too.

Who's been moving audio around with wires longer that the "Phone Company". Think about the distance they move signals and the fact it sounds as good as it does on the other end.

Later
Bruce
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Old 15th October 2002, 03:39 PM   #4
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I've made cables from CAT5 netwrk cable and I have to say they work quite well.

Although your point about the phone companies is a good one, don't forget that the range of frequencies down the phone lines are limited (the phone company filter out high and low stuff that they deem not necessary).

DIY at it's best is making something for very little money that works well - these cables are a case in point.

Also another place to find cheap CAT5 cables is from network installers who have offcuts from large reels that they quite often would throw away otherwise.

Hope this helps.

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Old 15th October 2002, 08:44 PM   #5
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Corn-Picker,

I've made the CAT5 cables you're looking at. The difference is very subtle, at least with the mid-fi reeiver I am using now. I expect the difference will be more noticeable once I finish my Zen V4 monoblocks.

I wouldn't worry about the capacitance. Any amp that becomes unstable driving that amount of capacitance isn't worthy anyway.

About CAT5 versus phone cable: CAT5 has much lower inductance and higher bandwidth, which is the whole reason for building these cables to begin with. Phone cable will work fine, but probably won't sound a whole lot better than zip cord.

Keep in mind that standard CAT5 cable doesn't have the teflon insulation that you want for these cables - you need to find plenum-grade CAT5. I had the supplier check with the manufacturer to ensure that the cable I used had teflon insulation.

As for your surrounds, I wouldn't suggest trying to use these cables, as the amount of work would be absolutely mind-blowing (see below).

Which brings me to my final point... Be prepared for a LOT of work! Especially if you go with the full 27 pair cables, as I did. Be prepared for long nights of braiding and sore hands. It takes a while to get the hang of it, and get the braiding tight and consistent.

Still, it's a great project, especially during the winter when there isn't much else to do.
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Old 15th October 2002, 09:02 PM   #6
HDTVman is offline HDTVman  United States
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I have used both Cat5 and phone cable. Is the Cat5 better? Maybe a little. Are they both better than zip cord? You bet, and it's not hard to hear the difference.

As for the difference between Cat5 and phone cable, well the extra work to braid the Cat5 just isn't worth it to me. With the phone cable just make sure that one half of each twisted pair is + and the other is -.

As for the frequency response, the 20 foot, 25 pair phone cable I've tested is flat past 100kHz. into an 8 ohm resistive load and shows good square waves to 30kHz. at least with my test setup. Just so you know thats all the test equipment will do. (cheezy generator)

Later
Bruce
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Old 16th October 2002, 12:16 PM   #7
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"About CAT5 versus phone cable: CAT5 has much lower inductance and higher bandwidth,"
Yeah right - are you sure that you understand what you are talking about ?.
CP, to use the 6, 12,20 or 25 pair cable, strip the sheath back 4 inches or so, fan out all the colour/white pairs, seperate the pairs neatly into two groups according to white or colour, and with a piece of cloth stroke and straighten all these wires neatly, and mark a strip length on each wire with a black marker pen.
Strip all the wires, and then taking all the wires of one group, carefully fom these wires into a single round twisted group, and then take a pair of large pliers and twist the exposed wires neatly and trim to length with sharp cutters, and repeat this process for the other group (and ends) - soldering together the ends is optional.
For 20 pair this will give a conductor diameter of about 4mm - this is plenty of copper conductance, even really high power systems.
With practice you can do 4 20 pr ends in 30 minutes or so.

CP, the thing happening here is that you have 20 nicely closely twisted pairs in parallel, so the total series inductance of a 20 pair cable is 1/20th the inductance of a single pair - in other words virtually zero inductance, and close to perfect individual pair balancing so any RF/noise pickup is minimal.
According to theory a single pair exhibits a characteristic impedence of around 150 ohms or so, so a 25 pair would likely have a characteristic impedence of around 6 ohms.
Bruce, are you able to confirm this for us ?.
In my experience (and Bruces ?), 20/25 pair cable gives is a really good, deep, solid, clean, fast, and just plain nice resultant with most amps and speakers and the result is not subtle WRT to other cables.
Indoor phone cable comes in a nice buff coloured round sheath that is unobtrusive visually, is fine for long runs, and can be painted over in permanent installations, and is cheap (Double Big WAF !).
Visually, practicality and effort wise, I think the Plaited cat5 idea is a huge waste of time.
I would try the 12/20/25 pair first, and then you have a reference.

Eric.
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Old 16th October 2002, 01:24 PM   #8
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YA, ,What mrfeedback said. No intended. I have been using phone cable for years and haven't heard anything enough better to get me to replace it. In fact most stuff doesn't sound as good.

As for impedance: I measured a 25 pair 18 foot cable at 7 ohms with a TDR. I don't say that this makes any difference but it is interesting.

Later
Bruce
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Old 16th October 2002, 01:45 PM   #9
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Quote:
Originally posted by mrfeedback
Yeah right - are you sure that you understand what you are talking about ?.
I think your choice of words could have been a little more diplomatic.

If you think CAT5 doesn't have greater bandwidth than phone cable... Try pushing 1Gb/s of data through your phone cable. CAT5e is rated at 350MHz. I haven't done any measurement, but I'll bet the inductance is significantly lower on the CAT5 with teflon insulation. Now, whether or not the difference is audible, is a matter open for debate.

Yes, the braiding is a pain in the ****. Here is the theory behind it, according to Chris VenHaus:

"Symmetrical field interactions: By using the braiding technique described, it substantially reduces any asymmetrical field interactions since no pair (or wire) 'rides' on either the inside or outside of the cable more than any other pair/wire."

This may or may not have an sonic benefit. For me, it was more a matter of aesthetics. It makes for a much neater cable than many strands of CAT5 tied together.
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Old 16th October 2002, 01:58 PM   #10
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Default Audio Band Transmission Lines...

Bruce, chill brother, my snide remark was directed at mr Sparhawk.
I was agreeing with you, and you with me I thought.
I have been using it for years too, and have found it to be consistently good and better than anything else, and so much so that I don't bother to use anything else, and when I hear systems using other cable I find them to be electrically/sonically wrong.
Thanks for the TDR measurement - that is what I was after.
I think that a matched line/load system is important.
Although strictly/theoretically speaking cable inductance and characteristic impedence ought not to be a consideration for the audio band, realistically speaking the real world parameters of negative feedback systems, induced RF noise, and spurious RF output of digital sources IMO mandate that standard transmission theory matched lines/load practises be implemented.
This is conditional to a flat loudspeaker impedence curve, and my experiments of LSP impedence compensation in conjunction with 25 pair cable gives long term listening/living with results far superior to any other cable that I am familiar with.
I find better bandwidth low and high, bigger better truer transients, less distortion over the whole band, cooler running amps and no speaker breakages.

Eric.
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