Speaker cable/Microphone cable......interchangeable?

surfguy13

Hi Guys

I need to make up some short runs of speaker cable and seem to have loads of instrument cable and microphone cable but very little speaker cable.  Instrument cable is, I assume, out but wondering if microphone cable can be used instead of speaker cable?

Cheers

Sporky

Not successfully, no.

octatonic

Using a speaker cable as a mic cable = noise.

Using a mic cable as a speaker cable = FIRE!

ESchap

Get the right stuff Guy, it potentially carries too much current for instrument cable. If you want to make your own, I use old garden mower cable. It's ideal spec and it's bright orange so not easy to confuse with my guitar leads.

viz

Is that really standard practice or just fretboard forum practice? I know I for one have exclusive 100% genuine old lawnmower cable for all my speaker cables and I know of many other forumites who do, but what about the rest of the world?

ESchap

Don't think it's a worldwide practice, it come up many times on the old forum. But it works well and a good way of using up old cable, so what's not to like?

octatonic

viz said:

Is that really standard practice or just fretboard forum practice? I know I for one have exclusive 100% genuine old lawnmower cable for all my speaker cables and I know of many other forumites who do, but what about the rest of the world?

It is fairly common.

I don't do it myself- I have some heavy duty 12 gauge speaker wire that is impossible to mistake for speaker cable because it has clear casing.

ecc83

This comes up regularly.

No, speaker cable cannot be used for signals* it will hum like a cnt.

No, "guitar" cable should not routinely be used for speakers but even "worse case" 100W amp to 4 Ohm cab is unlikely to cause a problem except perhaps with a cheap curly lead. A decent guitar lead will get you out of the cak for a night.

Yes to Orange garden cable. The 6amp stuff is more than good enough for gitamp duties. For those that fear fires...Do your jack plugs get hot? No? Well then, neither will the wire!

*Mind you, years ago, before taxi PMRs and transistors we got away with furlongs of twin twisted clear mains lead for 30Ohm balanced mics!

Dave.

ICBM

Actually, at the risk of scaring some people, most microphone cable will work very well as speaker cable, at least if you're not talking about PA-type power levels. It's far more suitable than 'instrument' cable, because it has two proper cores instead of using the shield for one of them - the signal cores are usually heavier gauge too.

(It is important to check the core gauges though - some mic cable does have very thin, usually braided cores... I wouldn't use that for a speaker cable.)

If you're going to make a speaker cable out of it I'd probably leave the shield unconnected at both ends too, to avoid any capacitance issues, although they're almost irrelevant anyway normally.

Power cable makes really excellent speaker cable - I would actually use this by choice over most commercial speaker cable, for stage use. It's physically robust, will handle high currents and is cheap, or free if you use old stuff - and I don't believe there is any detectable sound difference between it and 'proper' speaker cable at any power level you're likely to find with a musical instrument amp.

p90fool

viz said:

Is that really standard practice or just fretboard forum practice? I know I for one have exclusive 100% genuine old lawnmower cable for all my speaker cables and I know of many other forumites who do, but what about the rest of the world?

I use white mains cable for the same reason, I can spot them easily in a box of leads, as I never buy white guitar leads.

ICBM

Same here - I use white, grey or orange for speaker cables.

surfguy13

Wow!  That is all unbelievably helpful!!  I can't believe that old lawnmower cable or mains cable will do the job.  Give me that any day of the week over buying what seems to be very expensive speaker cable.  I'm not just being tight, it's just that I don't have any speaker cable to hand bar the cables I'm already using which are the right length.

Does the mains/lawnmower cable need to be 2 core or can it be 3 core and just use two of the three wires?

Sporky

Either is fine.

Mains cable is electrically perfect for speaker use.

ICBM

Absolutely fine just to use two of the wires.

It's not only cheaper, I actually think power cable is superior to most 'proper' speaker cable which is a classic case of marketing trumping physical and electrical reality.

surfguy13

Brilliant......thanks to all who have commented here.  I shall get the soldering iron out and head for the shed to do battle with the lawnmower!!! 

Sporky

Plus that gets you out of mowing the lawn.

surfguy13

Sporky said:

Plus that gets you out of mowing the lawn.

ecc83

+1 for twin "balanced" mic cable. I have some old stuff that could easily cope with a 2kW fan heater!

Re capacitance: Mic cable makes excellent guitar cables, just tie the "black" conductor to shield since this give the lowest capacitance and also stops the cable from being microphonic.

No valve output stage should be embarrassed by even a hundred nF of capacitance and that would be one mother of a mic cable! Transistor op stages might be fussier, especially very old designs but even here you would need a very long lead, running a tranny head out of a studio control room say? Maybe on a snake.

One downside for mic cable for speakers is that if it is "spiked" a short is almost inevitable. Again, valves won't care (for a while!) but old, feeble transistors will!

Money saving tip. Use cheap ass'ed plastic jack plugs for (orange of course!) speaker leads but beef them up with heatshrink sleeving. Also helps with ID since most git-gods know that you never use an unscreened jack plug on a front end.

Dave.

ecc83

HTF does one edit?

Anyhoos. Mic cable can also solve a serious RFI problem.

Tie black at one end to screen as before but at the other leave the screen disconnected (heatshrink it out of harm's way) and just use "red" and black for hot and screen tother end. 

The result is what I call a "shielded return" cable and it keeps all the RF energy circulating in the screen, there being no net current of either return signal or RF in that screen.

Dave.