alexclaber Posted June 10, 2009 Share Posted June 10, 2009 I've been stripping the wallpaper in our house recently using one of those steam devices. Brainlessly I left the extension lead mostly coiled and then after a while started wondering what the strange smell was. If it hadn't been so pungent I think the lead would have melted its insulation together into one solid mass. Fortunately even a 3kW bass amp isn't going to push more than a fraction of its power averaged over time but still... Alex Quote Link to comment Share on other sites More sharing options...
Musky Posted June 10, 2009 Share Posted June 10, 2009 [quote name='DanOwens' post='510680' date='Jun 10 2009, 10:00 PM']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[/quote] Coils of wire with a current flowing through them create a magnetic field which produces a back EMF. It is effectively a choke which provides resistance to the current, and as a result a build up of heat. Heat adds even more resistance in the circuit which just exacerbates the problem, leading to melt down. Which is why you should always uncoil any mains leads. Quote Link to comment Share on other sites More sharing options...
AdamWoodBass Posted June 10, 2009 Share Posted June 10, 2009 [quote name='thisnameistaken' post='509818' date='Jun 10 2009, 03:00 AM']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] Ah good old MOR strikes again! Never trusted the guys in there as far as I could throw them! They always used to offer me stupidly low trade in prices for gear and whenever I protested the response was always "well we've got to make a bit of profit!" I once tried out a Yamaha BB605 in there, fell in love with it and went down the street to what used to be Rockolla and ordered one from them just cos I didn't want to spend my money in MOR lol! Anyway to stay on topic, at a local church they have a lovely Hartke hybrid valve rig and the speaker cable keeps going walkies. A while ago someone tried using a guitar cable when the speaker cable had done its regular dissapearing act. The result was a melted guitar lead and a rather expensive repair bill for the amp. I've always used speakons, its just so much safer. As previously mentioned in this thread you can't touch them and they can't touch anything around them so that stops the potential 500 watts of power grounding itself and blowing your amp to bits or worse grounding itself through you and blowing you to bits! A decent amp tech would probably be able to replace the jack connector on your cab to a speakon for not a lot of money and provided obviously that your amp has a speakon output it would be a very worthwhile investment. Quote Link to comment Share on other sites More sharing options...
51m0n Posted June 11, 2009 Share Posted June 11, 2009 Only thing I really dont like and dont understand about the Hartke LH500, it has jack speaker outs I mean why would they do that? Its not going to be a significant change in component cost or time to put the correct connector in there is it. Now I have to wait until its out of warranty and do the mod myself. Bah!!!! Quote Link to comment Share on other sites More sharing options...
Beedster Posted June 11, 2009 Share Posted June 11, 2009 [quote name='obbm' post='510735' date='Jun 10 2009, 10:58 PM']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.[/quote] Another clue is that it will likely sound sh*te, even at quite low volumes. I did it with a TE 250 head going into a Marshall 115 (both with jack socket) a few years back and the sound was quite distorted, even at low volume, and enough to alert me to the fact that something was wrong. Before I turn on an amp I always turn the gain and volume down and then step it up to living room levels to check things are working OK before going to stadium volume (OK, small pub volume:) ). I guess had I not done so that day I would have melted the cable and blown the head. I did a course in electronic music technology in the early 80's and saw a few interesting examples of the interesting things that happen when flesh and bone meets high ampage, and as a result have a healthy distrust of all thing electrical. Personally I think it's stupid to the point of being almost criminal that manufacturers are allowed to build high voltage/ampage electrical kit with such poor risk control. I also think too many musos don't study even the basics of electrical safety Chris Quote Link to comment Share on other sites More sharing options...
hubrad Posted June 11, 2009 Share Posted June 11, 2009 [quote name='Beedster' post='510939' date='Jun 11 2009, 10:25 AM']I did a course in electronic music technology in the early 80's and saw a few interesting examples of the interesting things that happen when flesh and bone meets high ampage, and as a result have a healthy distrust of all thing electrical.[/quote] I've learnt electrics from the practical side, and I have a healthy respect for electricity; basically it will go any where you let it, so the art is only letting it go where you want it to. [quote name='Beedster' post='510939' date='Jun 11 2009, 10:25 AM']Personally I think it's stupid to the point of being almost criminal that manufacturers are allowed to build high voltage/ampage electrical kit with such poor risk control. I also think too many musos don't study even the basics of electrical safety Chris[/quote] Yup, electricity is 1) Very useful and 2) potentially lethal. I think it's the responsibility of the manufacturers to make a piece of kit as safe as possible, and the resonsiblity of the user (i.e. us lot!) to use it properly. Amps are high voltage equipment; we can't really get away from that one, so we need to be aware of just what we are throwing in the back of the van. Most I think we've all seen way too many dodgy mains sockets in venues (even schools! ) and damaged mains cables beloniging to gigging musos. Quote Link to comment Share on other sites More sharing options...
thisnameistaken Posted June 12, 2009 Share Posted June 12, 2009 [quote name='51m0n' post='510902' date='Jun 11 2009, 09:41 AM']Only thing I really dont like and dont understand about the Hartke LH500, it has jack speaker outs [/quote] Yeah that is a bit weird for a 500W amp. Quote Link to comment Share on other sites More sharing options...
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