Using CAT5 as speaker wire

[awhite1159]

I recently replaced my SS amp with a tube based amp. I currently have 12 gauge stranded copper wire as my speaker wire. Is CAT5 only recommended when the amp is solid state? I have plenty of that stuff laying around being involved with computers at work. Another thing I wanted to mention which goes back to my amateur radio days is that I remember reading about something called the 'skin effect' when using single conductor wire. It stated that as the frequency increased the current flow tended to travel along the outside of the conductor thereby increasing impedance. I know it was a concern with RF but is it a concern with audio?

[AndrewT]

Hi,
how you assemble your CAT5 wires into a speaker lead will determine the capacitance and inductance of your cables.
These two characteristics must be compatible with the amplifier.
It does not matter whether it is SS or valve. Compatability is paramount.

[Brett]

Skin effect isn't relevant at audio frequencies.
I used to use cat5, but short runs to horns. I've seem some SS amps go into apoplexy when connected with multiple braided runs where the capacitance is high. Andrew is correct when he said compatability is paramount.

[Luke122]

I've made my own Cat5, using 3 strands per side. I braided them together, and then seperated the colored and striped wires to + and -. Banana plugs on the amp end, and heat shrink at both ends to keep it from unraveling.

The run is approximately 12ft in length, and I've had no problems at all with my Super T-Amp. In fact, the gain in quality was considerable, and everyone who passes through my office is amazed as well.

[planet10]

I happilly use a single pair of strands with my tube amps.

dave

[loninappleton]

Originally posted by Luke122
I've made my own Cat5, using 3 strands per side. I braided them together, and then separated the colored and striped wires to + and -. Banana plugs on the amp end, and heat shrink at both ends to keep it from unraveling.

The run is approximately 12ft in length, and I've had no problems at all with my Super T-Amp. In fact, the gain in quality was considerable, and everyone who passes through my office is amazed as well.

This going to sound stupid but I don't know how to assemble
banana plugs.

signed, tired of messing with screw terminals.

[lydan01]

I've seen some examples on the web where people have tied together massive bundles of Cat5 wire - yet other people are using just a single twisted pair of wires...

Are there any rules of thumb for determining what is best used and when?

[Scottmoose]

Nothing hard & fast. Depends on the speaker and amplifier, and what you're trying to achieve. As a basic ROT, if running a lowish Q driver, the higher the ouput impedence (damping factor) of the amplifier, then thinner wire will probably work better. But that's not hard & fast, as you can also use thin wire with low DF units too.

[OzMikeH]

Huge bundles of cat 5 are popular because the cable is cheap and people think that if a little bit is good then a lot must be better. It's a good way to destroy an unstable amplifier. Braided cat5 is effectively two conductors with very large surface areas very close together separated by an insulator. It's a capacitor.

Look at it this way. Your speaker is usually 8 ohms. 24 AWG wire is 0.03 ohms per foot. Assume your speaker cables are 10 feet long, so the resistance of the whole cable (from amp to speaker and back) is 0.6 ohms. You lose just under 10% of your signal, sounds like a lot. 10% is less than 0.5dB. That $25 per metre enormous monster cable conducts less than 10% better than 24c per metre cat 5 for short runs of cable

It's not unusual to have a 0.5dB error in a typical consumer product's volume control between channels. Most people wouldn't even notice such an error.

Depending on the particular driver / cabinet combination that little loss of signal (and damping factor) can actually sound better than a huge cable.

[AndrewT]

Hi,
and that extra resistance is just enough to push a speaker that was verging towards boomy into very pronounced boom.
Take care with longer speaker leads.

My solution: Keep them short to very short.
reduces inductance
reduces capacitance
reduces resistance
reduces interference.