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Bass Amp To Bass Cab - Instrument Or Speaker Cable?


basskit_case
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Wanted to start a new thread on the merits of Speaker Cables Vs Instrument Cables for connection Heads to Cabs.

In deciding whether it was worth the risk of using a Instrument Cable I found [url="http://www.sweetwater.com/forums/showthread.php?17485-Proper-cable-from-bass-amp-to-speaker"]this[/url] thread, the majority of people suggest that you shouldnt do it because it will blow all your gear up, but the last post says that you can use an instrument cable and it will be fine. What do people here think?

BTW I have made a speaker cable purchase from OBBM, gone with the majority and not risked the instrument cable.

Edited by basskit_case
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If you don't have a speaker cable with you and you're desperate, you [i]can[/i] use a decent instrument cable to connect - that is, it will 'work' - but it is [i]not [/i]designed for the job and I would advise only doing this in an emergency. I have done it recently with my 240W RMS solid state Ampeg and it worked fine, but it was a small cabinet at relatively low volume. I still didn't feel comfortable with it. I don't think I'd have tried it with anything more sensitive / valuable, or at higher volumes. It's not just the cable you're risking, it could damage the amp or the speakers.

I'm no electrical/electronics engineer, but as I understand it instrument cables are designed to transmit very low power signals, not the high energy signals that an amplifier needs to transmit in order to move those speakers at high velocity. Speaker cabinets are passive, remember, so the electricity required to move the coils all comes down that cable! It stands to reason that a specific design of cable should be used.

Gentlemen, please feel free to correct any inaccuracies - I'm here to learn :)

Cheers, Stuee.

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It is something that has gained momentum over time, particularly as amps have got more and more powerfull

In the 60s a lot of us used whatever lead was available, screened or not, with no apparent problems, but a 100w amp was conisdered a big amp whereas now its considered small

I wouldnt worry id I was using it at home, but why run the risk if you dont have to for the sake of a few quid

your amps cost more than that

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[quote name='basskit_case' post='1103201' date='Jan 26 2011, 09:26 AM']Wanted to start a new thread on the merits of Speaker Cables Vs Instrument Cables for connection Heads to Cabs.

In deciding whether it was worth the risk of using a Instrument Cable I found [url="http://"%20<a%20href="http://www.sweetwater.com/forums/showthread.php?17485-Proper-cable-from-bass-amp-to-speaker""%20target="_blank">http://www.sweetwater.com/forums/showthrea...o-speaker"</a>"]this[/url] thread, the majority of people suggest that you shouldnt do it because it will blow all your gear up, but the last post says that you can use an instrument cable and it will be fine. What do people here think?

BTW I have made a speaker cable purchase from OBBM, gone with the majority and not risked the instrument cable.[/quote]

Well whoever it is that is saying it's fine to use an instrument cable is right in theory but wrong in practice.
Yes, an instrument cable will work just fine for a while on an amp that is gently used at home, but at some point it is inevitably going to end up being used hard.

Shielded cables that we all generally use have a shield (obviously!) and a thin cable running up inside it.
That thin cable is even thinner than it looks - it has insulation on it and often a second sheath around that to make it noiseless.
Shove enough amplified signal through that thin little piece of wire and it's gonna get warm.
If it gets really extreme and manages to melt through the insulation it's got a good chance of shorting out against the shield - dead short circuit across the output of your amp...

A decent speaker cable is just two whapping great wires that have no chance of melting under normal conditions - it might cost a couple of quid more than a cheapy guitar lead, but it's a damn sight cheaper than a potential amp repair.

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Instrument cables carry only the tiniest of voltages and currents. Speaker cables should really be regarded as power cables. They are totally different applications and require totally different cables, for all the reasons mentioned above.

The real problem, I think, is the stupid industry practice of using 1/4-inch jacks for everything. Half our band have trouble figuring out how to connect the PA together and I've watched them plug speakers into line inputs before now, presumably simply because the cables fit. :)

I use speakon connectors on my speaker cables, so there can be no confusion. It's a shame they are not more widely used.

It's a pity the music industry hasn't followed the IT world - it's almost impossible to incorrectly connect all the bits of a PC together because of the different connector types and colour-coded plugs and sockets. But the humble jack is now a universal standard with a long and honourable history, so I don't expect it will change anytime soon.

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+111

A friend of mine (really, no not me) managed recently to plug his 4x8 speaker cable into his fx return, the cab went microphonic, fed back through his 1x15 and buggered his amp...

Cheers

Mark
[quote name='flyfisher' post='1103284' date='Jan 26 2011, 10:35 AM']Instrument cables carry only the tiniest of voltages and currents. Speaker cables should really be regarded as power cables. They are totally different applications and require totally different cables, for all the reasons mentioned above.

The real problem, I think, is the stupid industry practice of using 1/4-inch jacks for everything. Half our band have trouble figuring out how to connect the PA together and I've watched them plug speakers into line inputs before now, presumably simply because the cables fit. :)

I use speakon connectors on my speaker cables, so there can be no confusion. It's a shame they are not more widely used.

It's a pity the music industry hasn't followed the IT world - it's almost impossible to incorrectly connect all the bits of a PC together because of the different connector types and colour-coded plugs and sockets. But the humble jack is now a universal standard with a long and honourable history, so I don't expect it will change anytime soon.[/quote]

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Wise choice going with OBBM - his cables are amazing, and especially for the price.

I`m not a techie person by any means, but I look at it as speaker cables are made for speakers, intrument cables are made for instruments. Hopefully, as long as I can recognise each, I`ll have no problems.

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[quote name='basskit_case' post='1103201' date='Jan 26 2011, 09:26 AM']Wanted to start a new thread on the merits of Speaker Cables Vs Instrument Cables for connection Heads to Cabs.

In deciding whether it was worth the risk of using a Instrument Cable I found [url="http://"%20<a%20href="http://www.sweetwater.com/forums/showthread.php?17485-Proper-cable-from-bass-amp-to-speaker""%20target="_blank">http://www.sweetwater.com/forums/showthrea...o-speaker"</a>"]this[/url] thread, the majority of people suggest that you shouldnt do it because it will blow all your gear up, but the last post says that you can use an instrument cable and it will be fine. What do people here think?

BTW I have made a speaker cable purchase from OBBM, gone with the majority and not risked the instrument cable.[/quote]

Have you never seen 'Magic smoke' it is cool!

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[quote name='flyfisher' post='1103284' date='Jan 26 2011, 10:35 AM']The real problem, I think, is the stupid industry practice of using 1/4-inch jacks for everything. Half our band have trouble figuring out how to connect the PA together and I've watched them plug speakers into line inputs before now, presumably simply because the cables fit. :)

I use speakon connectors on my speaker cables, so there can be no confusion. It's a shame they are not more widely used.[/quote]


Huge +1.

If an amp doesn't have a Speakon connection it'd make me thing twice about buying it. I really don't see why 1/4" are still used as speaker cables, speakons are a much better alternative.


On a similar note i got a call from my keys player the other week who'd carelessly plugged a random cable into one of the sockets of his newly acquired synth - apparently it made a nice burning/melty smell and his synth doesn't work any more!

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I use 2.5mm two core mains cable for my speaker cable (rated at 30A).. It's cheap at about 80p a metre and can cope with modern amp current loads without heating up too much.. OBBM uses 4mm cable in his Bass cables .. Why have a powerful amp and restrict the amount of current it can flow to your cab?

Edited by markstuk
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If you open up the jack plug (if you can) You should be able to tell the difference between an instrument cable and a speaker cable. You'll see in the top picture, the ground connection acts as a shield as it is wrapped around the centre cable. This is great for helping to keep noise at bay. However, should you ram a good few hundred watts down the cable and there is a fault, the centre core shield could melt and short circuit the amp connected to it, thus unleasing said 'magic smoke'.


Instrument cable:


Although this picture below isn't great, you can see two separate cores with their own insulation, thus giving a far greater protection against shorting. The actual core of each wire in a decent speaker cable will be much much thicker (heavier gauge) too and this can carry a greater current. To give an example of what each cable has to contend with, guitar signals are usually in the milliampere range (mA) whereas the output of an amplifier is 100x greater in the range of Amperes!

Speaker cable

I know which I would connect to my beloved bass amplifiers! - Infact - the speaker cables I use are massive! 2x4mm oh and yes, of course - from OBBM!

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[quote name='markstuk' post='1103500' date='Jan 26 2011, 12:41 PM']I use 2.5mm two core mains cable for my speaker cable (rated at 30A).. It's cheap at about 80p a metre and can cope with modern amp current loads without heating up too much.. OBBM uses 2.5 mm Klotz cable in his speaker cables as well.. Why have a powerful amp and restrict the amount of current it can flow to your cab?[/quote]


Correction: I use 4-sq.mm. 224 strand cable for bass amp leads, 2.5-sq.mm. for guitars. The 4-sq.mm. has a very low resistance which keeps the damping factor high and allows tighter control of the speaker driver especially near its resonant frequency.

The centre conductor of an instrument cable typically has a cross-sectional area of 0.22-sq.mm. which gives a higher resistance and a lower damping factor.

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Apologies.. Post modified.,.. :-) 4 mm core twin cable is about £2.50 a metre and rated at 45A normally.. And OBBM's cables are such good value you'd need to have a good reason to make your own, or be a dab hand at electrical stuff and happy to buy cable in volume..

[quote name='obbm' post='1103545' date='Jan 26 2011, 01:04 PM']Correction: I use 4-sq.mm. 224 strand cable for bass amp leads, 2.5-sq.mm. for guitars. The 4-sq.mm. has a very low resistance which keeps the damping factor high and allows tighter control of the speaker driver especially near its resonant frequency.

The centre conductor of an instrument cable typically has a cross-sectional area of 0.22-sq.mm. which gives a higher resistance and a lower damping factor.[/quote]

Edited by markstuk
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[quote name='basskit_case' post='1103201' date='Jan 26 2011, 09:26 AM']....but the last post says that you can use an instrument cable and it will be fine. ....[/quote]

I'm baffled. The last post on that thread definitely does [b]not[/b] say that it's ok to use an instrument cable between amp and cab. He was contradicting some of the details an earlier poster gave about why it was not ok, but he never said it was ok.

For example he writes "[b]The main reason not to use[/b] a shielded cable for connecting a speaker is .... it will heat up considerably, maybe enough to melt the insulation and produce a short. Most amplifiers don't like running into a short, and the [b]magic smoke tends to come out of the amp's expensive little parts[/b]. ;-)"

And later on he says:
"most "guitar" cables will not have enough copper in them to function well in such an application."
(the application being as a cable from amp to speaker).

He does say
"Such heavy-gauge shielded cables *do* exist",
but:
"they're just not commonly found in music stores."

Or am I missing something from his post? (Or am I looking at the wrong post? I did have to edit your link to get it to work!)

Edited by mart
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[quote name='mart' post='1103616' date='Jan 26 2011, 01:37 PM']Or am I missing something from his post? (Or am I looking at the wrong post? I did have to edit your link to get it to work!)[/quote]

No that's the right post.
I started reading through it but as soon as I saw the double negative I gave up. :)

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What can I say, I am knew at this, but I thought the penultimate paragraph refered to instrument cable use:

[quote]A 400-watt bass
head driving a 4-ohm box will put ten amps
through the cable; if it was forty feet long, you
might lose a portion of your power as heat in
the cable, but at three feet long that effect is
negligible.[/quote]

Edited by basskit_case
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[quote name='basskit_case' post='1103691' date='Jan 26 2011, 02:13 PM']What can I say, I am knew at this, but I thought the penultimte paragraph refered to instrument cable use:[/quote]

There's no way I'd put 10 amps through an instrument cable, the same as I wouldn't use a desklamp cable plugged in to a kettle!

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Put 10-amps down an instrument cable and it will melt. If you don't believe me try running your electric kettle on an instrument cable and watch it melt.

Lord Valve recommends 12-gauge cable. 12-gauge is the closest american equivalent to 4-sq.mm.


SAFETY WARNING - DO NOT USE YOUR INSTRUMENT CABLE TO POWER A KETTLE.

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[quote name='basskit_case' post='1103691' date='Jan 26 2011, 02:13 PM']What can I say, I am knew at this, but I thought the penultimte paragraph refered to instrument cable use:[/quote]

Yep, it is very confusing - I had to go back and read that paragraph and the earlier ones again to make sure of what he was saying in the paragraph you refer to. But he's talking about 12 gauge cable, not the 22 or 24 gauge that (he says) you get in instrument cables.

He's not going to win any awards for clear english. :)

But then nor am I! :)

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