Instrument/Speaker cables

[Hodge]

The other day, I was in the music shop in our town. It's not a shop that sees alot of business from me as a rule, since I've found in the past that the staff really don't have much of a clue.

This particular day, however, I desperately needed a speaker cable quickly. The woman in the shop was adamant that there was no difference between instrument and speaker cables and that a standard guitar lead would be fine.

Now, I'm not sure how or when I learned it, but I knew that that's not the case. What I didn't know was why?

After a bit of searching on here I've learned that there's a possibility of the conductors in an instrument cable melting together and causing a short if used for connecting an amp to a speaker.

So my question is: is this something that COULD happen, or something that is VERY LIKELY to happen, or even something that will DEFINATELY happen?

Also, is there a chance of any damage to the amp and/or speaker or is it just a case of the cable dying.

I'm trying to get an idea of just how bad the advice of the shop staff was and if it's the sort of thing that could potentially cause big problems for someone who knows even less than I do and simply took their word for it.

The answer will decide whether or not I can be arsed to kick up a fuss with the boss about the bad information being given by his staff.

[Musicman20]

[quote name='Hodge' post='509059' date='Jun 9 2009, 02:32 PM']The other day, I was in the music shop in our town. It's not a shop that sees alot of business from me as a rule, since I've found in the past that the staff really don't have much of a clue.

This particular day, however, I desperately needed a speaker cable quickly. The woman in the shop was adamant that there was no difference between instrument and speaker cables and that a standard guitar lead would be fine.

Now, I'm not sure how or when I learned it, but I knew that that's not the case. What I didn't know was why?

After a bit of searching on here I've learned that there's a possibility of the conductors in an instrument cable melting together and causing a short if used for connecting an amp to a speaker.

So my question is: is this something that COULD happen, or something that is VERY LIKELY to happen, or even something that will DEFINATELY happen?

Also, is there a chance of any damage to the amp and/or speaker or is it just a case of the cable dying.

I'm trying to get an idea of just how bad the advice of the shop staff was and if it's the sort of thing that could potentially cause big problems for someone who knows even less than I do and simply took their word for it.

The answer will decide whether or not I can be arsed to kick up a fuss with the boss about the bad information being given by his staff.[/quote]

OBBM will no doubt talk you through the technical side of why you have to use different cables. Basically, you cannot use an instrument cable to connect cab to amp. You need a good quality speaker cable from amp to cab.

[Hodge]

[quote name='Musicman20' post='509078' date='Jun 9 2009, 02:44 PM']OBBM will no doubt talk you through the technical side of why you have to use different cables. Basically, you cannot use an instrument cable to connect cab to amp. You need a good quality speaker cable from amp to cab.

[/quote]

Aye, I'm aware of that. What I'm after is what would happen if someone followed the bad advice given in the shop.

The reason I needed another cable was I'd just taken delivery of my lovely, new, lovely, lovely LM III .....did I mention it was lovely? and a pair of Aguilar DB 112s. I know that you've recently aquired an LM III too, so I'm sure you understand my reluctance to do a practical test and find out for myself.

[hubrad]

COULD happen.. I know plenty of folks who have got away with it for years!
I really wouldn't advise it, though, and once almost got into an argument when I wouldn't let one lot use one of my Cream cables as a monitor speaker lead rather than them walk to their car.
You could melt the cable if you overpower it enough - short your amp output and guess what?
Running power signal down a shielded cable also has some other inference which I don't fully understand, but I believe it's also potentially not good for your amp. Alex?
If you're in a rush for a speaker cable and no-one has one for sale, you're better off cobbling something up with as-heavy-as-possible 2-core mains cable, daft as it may sound.
Dunno if I'd bother to kick off about it, but worth taking their 'advice' with a pinch of salt!

[Bill Fitzmaurice]

[quote name='Hodge' post='509059' date='Jun 9 2009, 09:32 AM']Also, is there a chance of any damage to the amp[/quote]Yes.
[quote]I'm trying to get an idea of just how bad the advice of the shop staff was[/quote]Bad enough that said person should be summarily sacked.

[51m0n]

[size=7][color="#FF0000"]BANG!!!![/color][/size]

[51m0n]

Well maybe not that exciting but very very very not good. Not to mention not allowing your amp to do the right thing by your tone....

[BOD2]

That information is VERY bad, possibily m,ore so for bass guitar where the amplifiers tend to be higher powered than 6-string amplifiers.

The problem is that an instrument cable is designed to handle the very low signal levels (voltages) that are generated by, for example, a guitar pickup. There are two conductors - a central conductor that carries the signal and a braided "screen" that shields the signal from interference. The central signal conductor is very thin - perhaps 8 strands of very thin copper wire.

A speaker cable, on the other hand, has to handle the output power of an amplifier which might be anything from 30 Watts to 1000 Watts RMS. 1000 Watts (1 kilo Watt) is the the same power as the average single bar electric fire. Now imagine connecting an electric fire to the mains with an instrument cable and you'll get some idea of the potential problem.

A good speaker cable has much heavier gauge wire than an instrument cable. The conductors inside will look more like a mains cable than an instrument cable in order to handle the higher power. In addition to this the connections to the jack plug will also be heavier duty to cope with the higher load.

Yes, it is possible to use an instrument cable as a speaker cable and you may get away with if the power passing between amplifier and speaker is low. But if this power is high, then the instrument cable will blow like a fuse, leaving the amplifier outputs potentially open or short circuited, which can cause very expensive damage to the power section of the amplifier.

For this reason, never use an instrument cable as a speaker cable - not even in an emergency.

The shop gave very bad advice.

[Musicman20]

[quote name='Hodge' post='509089' date='Jun 9 2009, 02:56 PM']Aye, I'm aware of that. What I'm after is what would happen if someone followed the bad advice given in the shop.

The reason I needed another cable was I'd just taken delivery of my lovely, new, lovely, lovely LM III .....did I mention it was lovely? and a pair of Aguilar DB 112s. I know that you've recently aquired an LM III too, so I'm sure you understand my reluctance to do a practical test and find out for myself.

[/quote]

They should definitely give the member of staff a severe talking to.

They probably just wanted to sell what they had.

Hey...I think we are the only LM3 owners on here! Im using mine for a gig soon and some practices.

Re: Aggies...dont blame you mate. The Aggie DB cabs are seriously nice. Im thiking of getting 2 8 Ohm DB212 and getting rid of my Ampeg 810. I really like what Aguilar do.

Pics? Colours?!

[Paul_C]

It's been known for a guitar lead to catch fire if used as a speaker lead, because it's designed to work with the relatively small signal coming from a bass, not the extra load that comes out of an amp.

[hubrad]

[quote name='Paul_C' post='509112' date='Jun 9 2009, 03:08 PM']It's been known for a guitar lead to catch fire if used as a speaker lead, because it's designed to work with the relatively small signal coming from a bass, not the extra load that comes out of an amp.[/quote]
A rather more extreme case, but some neighbours a few years back almost killed their baby by running a fan heater on a fully coiled mains extension!

[Musicman20]

Just also realised you are a fellow Linconlshire bassist!

[Hodge]

Thanks for all that info, especially BOD2; that's just the sort of info I was looking for.

The shop in question isn't a specialist guitar shop by any means, they have a few guitars upstairs. As such I don't think their customer base is made up of more experienced players, more the beginner end of the market....lots of Stagg stuff etc.

That's what made me think that their badly informed staff were potentially much more dangerous, considering the people who would be recieving this sort of "advice".

Worse thing is it wasn't even a case of them jsut wanting to sell what they had in stock, since she eventually found a speaker lead. It was more a case of she didn't want to root through them all to find one if she could just 'fob me off' with the ones at the front of the rack.

I'll get out me pipe later, put on my 'retired colonel' voice and compose a strongly worded email to them.

Musicman20: Didn't realise you were round this way too. The Aggies are tweed, I decided if I was spending that sort of money I could wait two weeks for the Bass Merchant to get them over from the US. Glad I did too, they look gorgeous. If I can manage to get me arse in gear and buy some batteries for my camera I'll stick up some pics.

The first outing for the new rig was last weekend, but it was a strange garden-party type affair where we had to be fairly quiet, but even at low volume it sounded fantastic. In fact I'm quite pleased it was a quiet gig, gave me the chance to hear it a bit clearer and now I still get to look forward to giving it a good blast at the next proper gig.

[obbm]

Agree 100% with all that's been said.

As an example a typical instrument lead has an central conductor of 7 strands of 0.2 sq.mm. cable.

This equates to a total conductor diameter of 0.5mm.

The maximum recommended current for this size cable is around 0.6 Amp.

Many solid state amps have a voltage swing of around 100 volts.

Power = volts x amps = 60 watts

Simply put you shouldn't use an instrument cable with anything more than say a 50-watt amp.

I think I got that right. Anyone care to comment?

[Musicman20]

[quote name='Hodge' post='509179' date='Jun 9 2009, 04:09 PM']Thanks for all that info, especially BOD2; that's just the sort of info I was looking for.

The shop in question isn't a specialist guitar shop by any means, they have a few guitars upstairs. As such I don't think their customer base is made up of more experienced players, more the beginner end of the market....lots of Stagg stuff etc.

That's what made me think that their badly informed staff were potentially much more dangerous, considering the people who would be recieving this sort of "advice".

Worse thing is it wasn't even a case of them jsut wanting to sell what they had in stock, since she eventually found a speaker lead. It was more a case of she didn't want to root through them all to find one if she could just 'fob me off' with the ones at the front of the rack.

I'll get out me pipe later, put on my 'retired colonel' voice and compose a strongly worded email to them.

Musicman20: Didn't realise you were round this way too. The Aggies are tweed, I decided if I was spending that sort of money I could wait two weeks for the Bass Merchant to get them over from the US. Glad I did too, they look gorgeous. If I can manage to get me arse in gear and buy some batteries for my camera I'll stick up some pics.

The first outing for the new rig was last weekend, but it was a strange garden-party type affair where we had to be fairly quiet, but even at low volume it sounded fantastic. In fact I'm quite pleased it was a quiet gig, gave me the chance to hear it a bit clearer and now I still get to look forward to giving it a good blast at the next proper gig.[/quote]


Excellent

I am the same about the Aggies...as much as I will end up with a lightweight setup/neo cab in the future...you cannot beat those Aguilar 12s. Im thinking chocolate brown to go with my Orange....hence Chocolate Orange!

[BOD2]

[quote name='obbm' post='509190' date='Jun 9 2009, 04:21 PM']Simply put you shouldn't use an instrument cable with anything more than say a 50-watt amp.

I think I got that right. Anyone care to comment?[/quote]

That sounds about right - I wasn't sure of the actual figures.

The trouble is, you'll always get people who say "I've used instrument leads for my speakers for years and never had any problems" and from these figures you can see that if it's a good quality instrument lead and the amplifier is less than 50 Watts then they might get away with it.

Use a 300 Watt bass amp with the same lead, however, and you'll have problems !

The other issue here is that some cheaper instrument leads are very poorly made and the solder connections to the jack plug can be pretty poor as well. So you might get away with using a high quality instrument lead but if you pick up a poor quality one then it's a different story.

Much better to make it a rule never to use instrument cables for speakers and avoid any potential (and very costly problems).

Incidentally - it's always a good idea to clearly MARK speaker cables (e.g. with brightly coloured or something highly visible) so that you can instantly identify them on a dark stage.

[Hodge]

[quote name='Musicman20' post='509201' date='Jun 9 2009, 04:27 PM']Excellent

I am the same about the Aggies...as much as I will end up with a lightweight setup/neo cab in the future...you cannot beat those Aguilar 12s. Im thinking chocolate brown to go with my Orange....hence Chocolate Orange![/quote]

Mmmmm.....chocolate orange...........





......mmmm.......Dawn French eating chocolate orange........ I think I need a lie down.

[Stylon Pilson]

[quote name='BOD2' post='509211' date='Jun 9 2009, 04:33 PM']Incidentally - it's always a good idea to clearly MARK speaker cables (e.g. with brightly coloured or something highly visible) so that you can instantly identify them on a dark stage.[/quote]

Or swap the jack plate on the back of your speaker cabinet for a speakon.

S.P.

[Count Bassy]

[quote name='Stylon Pilson' post='509239' date='Jun 9 2009, 04:51 PM']Or swap the jack plate on the back of your speaker cabinet for a speakon.

S.P.[/quote]

+1.
Despite being used as such for years Jack plugs are really not suitable for speaker connections. The have exposed contacts which means that a loose cable end can easily short out against any metal object.

Speakons are far better bet since the contacts on both the plugs and sockets are finger/touch proof, they lock into place, and there is no chance of confusing them with instrument leads.

[thisnameistaken]

I'll happily out someone:

A few months back I asked the owner (owner!) of MOR Music in York (Fossgate) if he had any short speaker cables (I needed one that night). He said - and these are pretty much his exact words: "No, but you're in luck, because speaker cables are exactly the same as instrument cables".

After a brief exchange of posturing I said "So you'd happily put 300W down an instrument cable?" and he said "300W? No." and started rooting around, and eventually found a speaker cable he wanted to sell me for a tenner. It looked home-made and given my rapidly-declining opinion of his technical nouse I said no, and ended up borrowing one at the gig.

[quote name='hubrad' post='509128' date='Jun 9 2009, 03:22 PM']A rather more extreme case, but some neighbours a few years back almost killed their baby by running a fan heater on a fully coiled mains extension![/quote]

Whenever my girlfriend pulls out the hoover (exactly as often as I do - I do my share I swear!) I find myself uncoiling all the mains cable out of it (it's a Henry with the cable coiled inside it) and she rolls her eyes at me like I'm being all patronising. The sad part is she worked as a theatre tech for years - I thought she'd know this stuff.

Girls...

[DanOwens]

I use a Henry uncoiled. Why am I doing wrong oh wise sage?

That's not meant to sound sarcastic. I genuinely don't want to fry myself and would like to know the science.

Dan

[alexclaber]

Much as I'd like to test this out properly I'm not sure the protection circuitry on my amp will kick in quickly enough! Though saying that I guess I could do it with a mains supply and a load of big resistors...

This is one reason I only put Speakons on my cabs - removes the risk of using the wrong lead by accident or ignorance.

Alex

[tonybassplayer]

I have to admit that I was not really aware of this ( heard they were different but not THAT different )

Can someone please advise me as to how to tell one from the other ( i have two boxes of leads that I use at gigs, home etc and not entirely sure which are which )

On a similar note ( and this is good timing ) I want to give all my leads a good check over to see what is working and what may be faulty and wonder if a simple test by an avo meter would do ( I am assuming that some form of resistance/comtinuity test will determine possible internal problems )

Many thanks

[pete.young]

I guess we were lucky we survived the '60s/'70s, not knowing this stuff.

Then again, who had an amp more than a whopping 50W ? OBBM is right again, film at 11.

[obbm]

[quote name='tonybassplayer' post='510721' date='Jun 10 2009, 10:43 PM']I have to admit that I was not really aware of this ( heard they were different but not THAT different )

Can someone please advise me as to how to tell one from the other ( i have two boxes of leads that I use at gigs, home etc and not entirely sure which are which )

On a similar note ( and this is good timing ) I want to give all my leads a good check over to see what is working and what may be faulty and wonder if a simple test by an avo meter would do ( I am assuming that some form of resistance/comtinuity test will determine possible internal problems )

Many thanks[/quote]

Firstly the obvious in that many mass produced cables actually have printed on them what they are -Speaker Cable/Instrument Cable.

Next, if you can unscrew the cover, have a look inside the jack and see what sort of cable is connected.

If there are two identical sized conductor, individually insulated (red/black, brown/blue) then it is a speaker cable.

If the cable is co-axial, the insulated centre conductor soldered to the jack tip while the multi-stranded screen conductors are bunched together and soldered to the jack sleeve then it is an instrument cable.

Finally if you can't get into the jacks and there is no printing on the cable try measuring the resistance. If tip to tip and sleeve to sleeve measure the same then its probably a speaker cable, if the sleeve to sleeve is lower than the tip to tip then its probably an instrument cable as there are more conductors in the screen. Please note that this is only a rough guide and there is no substitute for seeing the actual cable.