Another speaker-wire/cable connect musing... looking for an EE response.

[biscuithead]

I have some junk speakers/amp in the garage that I listen too while at the bench. These are hooked up using Cat5e wire (24awg UTP). I take the blue and green twisted pair(4 wires), strip back 3/4" and twist them together, then the same with the brown and orange. This becomes my speaker cable...rudimentary, I know.
Question: Is using 4 of these 24awg wires (although insulated from each other) combined together any different from using just one? What I mean is, since we are taught that Electrons will "follow the path of least resistance", is combining these, increasing it's mass, and thus decreasing the resistance to electron flow. Or, since they are isolated from each other, except at the ends, would I get the same rating/resistance if I just used one of the 24awg wires.

The length that I am running these is between 30-40 feet, and I have never experienced any kind of anomaly due to under-sized inner-connects. The amp is some 90s BPC Sony @ ~60wpc, and the speakers are water-damaged CW D-9s.

The purpose of this question is that I am about to wire up yet another system in the house, and I am out of my "good" wire and I have a couple boxes of Cat5 kickin' around the garage... I was thinking about using it in a "I care about the equipment" system.

Let us please not float this down the $1000 cable vs $10 cable gutter... just a good-hearted discussion about combining insulated wires in a multi-wired cable... What happens? Hopefully an Electrical Engineer will have some input- Thanks!

 

[DaveVoorhis]

Four wires, connected at their ends, is effectively like four resistors connected at their ends. Thus, they are four resistors connected in parallel, the total resistance of which is 1 / (1/R1 + 1/R2 + 1/R3 + 1/R4). If we imagine the resistance of each individual wire is 1 ohm, then it's 1 / (1/1 + 1/1 + 1/1 + 1/1) = 1 / (1 + 1 + 1 + 1) = 1 / 4 = 0.25 ohms.

In other words, the resistance will be one quarter the resistance of using one wire.

 

[biscuithead]

Four wires, connected at their ends, is effectively like four resistors connected at their ends. Thus, they are four resistors connected in parallel, the total resistance of which is 1 / (1/R1 + 1/R2 + 1/R3 + 1/R4). If we imagine the resistance of each individual wire is 1 ohm, then it's 1 / (1/1 + 1/1 + 1/1 + 1/1) = 1 / (1 + 1 + 1 + 1) = 1 / 4 = 0.25 ohms.

In other words, the resistance will be one quarter the resistance of using one wire.

Thanks! Is the current rating on the combination 4 times more than a single wire?

 

[whoaru99]

Thanks! Is the current rating on the combination 4 times more than a single wire?

Theoretically the current rating would be equivalent to a wire of the same total crossectional area. This assumes perfect connection at each end and all the wires are same length, etc., so the current is equally divided.

So, from a discussion about speaker wires stand point, yes. Four 24ga wires have 4x more current capability than one 24ga wire.

 

[evsentry3]

Theoretically the current rating would be equivalent to a wire of the same total crossectional area. This assumes perfect connection at each end and all the wires are same length, etc., so the current is equally divided.

So, from a discussion about speaker wires stand point, yes. Four 24ga wires have 4x more current capability than one 24ga wire.

Because of the different twist rate of the different pairs, you will NOT have even close to the same length between the pairs. Effect is another question..

EV3

 

[whoaru99]

Because of the different twist rate of the different pairs, you will NOT have even close to the same length between the pairs. Effect is another question..

EV3

That's why I was clear to point out for speaker cable. If you were wiring an industrial application requiring hundreds or thousands of amps to be split uniformly would be a different matter, IMO.

 

[biscuithead]

Theoretically the current rating would be equivalent to a wire of the same total crossectional area. This assumes perfect connection at each end and all the wires are same length, etc., so the current is equally divided.

So, from a discussion about speaker wires stand point, yes. Four 24ga wires have 4x more current capability than one 24ga wire.

For this application (speaker wire), would it be accurate to say, that I am 4 times "safer" in using 4 wires of the cat5 twisted together, than just using one?
My end game here is to feel comfortable about using the Cat5 in this fashion, in this application.

 

[biscuithead]

Because of the different twist rate of the different pairs, you will NOT have even close to the same length between the pairs. Effect is another question..

EV3

I get that those electrons want to take the shortest highway home... but how about a pointed question:
Would you feel comfortable using this wire, in this application, this way? I am admittedly a CHEAPSKATE when it comes to speaker wire...

 

[whoaru99]

For this application (speaker wire), would it be accurate to say, that I am 4 times "safer" in using 4 wires of the cat5 twisted together, than just using one?
My end game here is to feel comfortable about using the Cat5 in this fashion, in this application.

Many people use twisted pairs of Cat5 for speaker wire.

Unless you are pushing a LOT of watts it will be fine.

The problem with even one strand of 24 ga wire in a typical stereo system is not so much current, but the series resistance it imparts can affect the sound at some (relatively) short point in length.

 

[biscuithead]

Many people use Cat5 for speaker wire.

Unless you are pushing a LOT of watts it will be fine.

The problem with even one strand of 24 ga wire in a typical stereo system is not so much current, but the added resistance it imparts will affect the sound at some point in length.

Aww-haww! I hadn't considered this... Although with DaveVoorhis response, I should have. Thanks for your input!

 

[Dr. Morbius]

I've done a few DIY Cat5 speaker cable sets. They've turned out pretty nice.

https://www.wirebarn.com/combined-wire-gauge-calculator_ep_42.html

 

[twiiii]

Would you use eight 1/16" water pipes to feed your house. How long do you think it would be before compromises set in. Now I'm not saying speaker wires can clog up, but what about capacitance between conductors diminishing highs. And depending on how the properties of the wire react with the impedance of the speaker and the back emf of a speaker with a low damping factor the bass can become sloppy loose and the high frequencies distorted. All that said if the wire were designed for speaker use as with other braided wires the performance can be very good. The point being the CAT 5 is not designed for use with loudspeakers. 16 awg zip cord would be a better choice.

 

[biscuithead]

I've done a few DIY Cat5 speaker cable sets. They've turned out pretty nice.

https://www.wirebarn.com/combined-wire-gauge-calculator_ep_42.html

WHAT! A COMBINED WIRE GAUGE CALCULATOR...
I didn't know such a thing existed, I am really revealing my ignorance.
Thanks for this!

 

[biscuithead]

Would you use eight 1/16" water pipes to feed your house. How long do you think it would be before compromises set in. Now I'm not saying speaker wires can clog up, but what about capacitance between conductors diminishing highs. And depending on how the properties of the wire react with the impedance of the speaker and the back emf of a speaker with a low damping factor the bass can become sloppy loose and the high frequencies distorted. All that said if the wire were designed for speaker use as with other braided wires the performance can be very good. The point being the CAT 5 is not designed for use with loudspeakers. 16 awg zip cord would be a better choice.

8 water taps feeding my house! Sounds like what a marketing man would call "redundancy", preparing for future "expansion".

But on a serious note, I get what you are saying. I guess for a twenty-dollar bill, I should just break down and buy some speaker wire.

 

[Schurkey]

I take the blue and green twisted pair(4 wires)...
...using 4 of these 24awg wires...

...The length that I am running these is between 30-40 feet

4 24-gauge wires combined is the equivalent to 18-gauge wire according to the web site linked previously.

"I" would not use 18-gauge wire in a 30+ foot length. I assume there's another 30+ feet of return wiring. 60+ feet of wire at 18 gauge is just too long--or too small, depending on your perspective.

There's probably nothing wrong with using that Cat5 cable as speaker cable in terms of safety; and if the length is kept short enough, maybe 18-gauge-equivalent is satisfactory...but WHAT IS THE IMPEDANCE OF YOUR SPEAKERS, how loud do you listen, and how big is the room--and the amplifier?

My speakers were sold as "4-ohm" nominal rating. I've modified them, the impedance is now lower due to some of the mods performed. I am not going to run a high-powered amp into low impedance speakers using 18-gauge wire. I'm currently using 12-gauge, but I have my eye on some inexpensive 10-ish gauge cable that used to be recommended by Bryston before they started selling their own "boutique" cable. (RG8-U) I don't want to rip my wall apart to install it, though.

If you have a heap of unused Cat 5, consider twisting all the ends together, and route an entire cable on the + side, and an entire cable on the - side. That gets you an equivalent to 15-gauge.

Or you buy a spool of 16-gauge zip cord "speaker cable" at the home-improvement store which will cost about twelve dollars, and take less time to install.

 

[biscuithead]

4 24-gauge wires combined is the equivalent to 18-gauge wire according to the web site linked previously.

"I" would not use 18-gauge wire in a 30+ foot length. I assume there's another 30+ feet of return wiring. 60+ feet of wire at 18 gauge is just too long--or too small, depending on your perspective.

There's probably nothing wrong with using that Cat5 cable as speaker cable in terms of safety; and if the length is kept short enough, maybe 18-gauge-equivalent is satisfactory...but WHAT IS THE IMPEDANCE OF YOUR SPEAKERS, how loud do you listen, and how big is the room--and the amplifier?

My speakers were sold as "4-ohm" nominal rating. I've modified them, the impedance is now lower due to some of the mods performed. I am not going to run a high-powered amp into low impedance speakers using 18-gauge wire. I'm currently using 12-gauge, but I have my eye on some inexpensive 10-ish gauge cable that used to be recommended by Bryston before they started selling their own "boutique" cable. I don't want to rip my wall apart to install it, though.

If you have a heap of unused Cat 5, consider twisting all the ends together, and route an entire cable on the + side, and an entire cable on the - side. That gets you an equivalent to 15-gauge.

Or you buy a spool of 16-gauge zip cord "speaker cable" at the home-improvement store which will cost about twelve dollars, and take less time to install.

Well the junk I have in the garage has been running like this for over 5 years... but your 12 dollar assessment does ring my bell. I'll spend a mint on a quad of Mullard EL34s, but 12 bucks for speaker cable, hell-naw!
I generally have scrap 12-2 or 14-2 romex laying around, but it has been ages since I've done any Resi-wiring.

 

[Schurkey]

My garage system is a 35-watt receiver and 8-ohm speakers connected with leftover 10- or 12-gauge Romex.

 

[biscuithead]

My garage system is a 35-watt receiver and 8-ohm speakers connected with leftover 10- or 12-gauge Romex.

A tip-o-da-cap to you!

 

[whoaru99]

Well, I figure it's about time for this.

http://www.roger-russell.com/wire/wire.htm#wiretable

 

[whoaru99]

If you have a lot of Cat5 and don't mind using 4 lengths of cable (two cables to each speaker) you could use all 8 strands for one conductor. That would be equivalent of 15ga.

Edit: Oh, I see this was already mentioned.