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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#121
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Jim Stewart wrote:
Mark Rand wrote: On 13 Mar 2005 00:48:06 GMT, wrote: For hi-fi speaker wire the 10ga zipcord offers dozens of strands per conductor, thus it has much greater surface area per unit length than solid conductor would. And THIS is what you want in order to conduct the higher audio frequencies, as they travel along the 'skin' of a conductor. More surface area=more skin. For longer lengths thicker than 10ga will reduce power losses. Welding cable (very flexible- many strands) would be excellent and certainly no more expensive than those rip-off gold plated 'monster cables'. At audible frequencies plating conductors with silver or gold has negligible effect. Only at rf frequencies is this needed to reduce losses. Twisted-pair are not fine enough to achieve what good quality zip cord can in this application. And '75 ohm characteristic impedance' has nothing to do with power transmission. Sorry to but in here, but there is a certain quantity of ******** in the above. Multiple strands have no effect whatsoever if they are in electrical contact. A 3/8" diameter welding cable is essentially identical in impedance to a solid cable of identical cross section. The only way to get multiple strands to give you an advantage with skin effect is to insulate them from each other and to regularly transpose the conductors so that each one ends up with the same impedance from end to end. I believe Bob Pease suggests the same thing. He said that *if* skin effect is an audible issue with speaker cables, you should take a 40 or 50 conductor ribbon cable and use the even conductors for one channel and the odd conductors for the other. I don't think he thought it would make any difference, but if you wanted to do something correct from a physics point of view that would be the best way. Why dont you just get some two inch soft copper tubing and cover it with a hose? John |
#122
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In article , john says...
Why dont you just get some two inch soft copper tubing and cover it with a hose? This is what they do for RF bomber power supplies. Except that they put the cooling water *inside* the copper tubing. No need for a hose. Jim -- ================================================== please reply to: JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com ================================================== |
#123
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john wrote:
Jim Stewart wrote: Mark Rand wrote: On 13 Mar 2005 00:48:06 GMT, wrote: For hi-fi speaker wire the 10ga zipcord offers dozens of strands per conductor, thus it has much greater surface area per unit length than solid conductor would. And THIS is what you want in order to conduct the higher audio frequencies, as they travel along the 'skin' of a conductor. More surface area=more skin. For longer lengths thicker than 10ga will reduce power losses. Welding cable (very flexible- many strands) would be excellent and certainly no more expensive than those rip-off gold plated 'monster cables'. At audible frequencies plating conductors with silver or gold has negligible effect. Only at rf frequencies is this needed to reduce losses. Twisted-pair are not fine enough to achieve what good quality zip cord can in this application. And '75 ohm characteristic impedance' has nothing to do with power transmission. Sorry to but in here, but there is a certain quantity of ******** in the above. Multiple strands have no effect whatsoever if they are in electrical contact. A 3/8" diameter welding cable is essentially identical in impedance to a solid cable of identical cross section. The only way to get multiple strands to give you an advantage with skin effect is to insulate them from each other and to regularly transpose the conductors so that each one ends up with the same impedance from end to end. I believe Bob Pease suggests the same thing. He said that *if* skin effect is an audible issue with speaker cables, you should take a 40 or 50 conductor ribbon cable and use the even conductors for one channel and the odd conductors for the other. I don't think he thought it would make any difference, but if you wanted to do something correct from a physics point of view that would be the best way. Why dont you just get some two inch soft copper tubing and cover it with a hose? The reason *I* don't do it is because I know it won't make any difference to my 53-year-old ears. Zip cord works fine. As to anyone else, do it if it makes you feel good. Put Slick 50 in your engine while you're at it... |
#124
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![]() The reason *I* don't do it is because I know it won't make any difference to my 53-year-old ears. Zip cord works fine. As to anyone else, do it if it makes you feel good. Put Slick 50 in your engine while you're at it... And if anyone here can hear it over the sound of machines running, they have much better hearing than I do! |
#125
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Jim Stewart wrote:
john wrote: Jim Stewart wrote: Mark Rand wrote: On 13 Mar 2005 00:48:06 GMT, wrote: For hi-fi speaker wire the 10ga zipcord offers dozens of strands per conductor, thus it has much greater surface area per unit length than solid conductor would. And THIS is what you want in order to conduct the higher audio frequencies, as they travel along the 'skin' of a conductor. More surface area=more skin. For longer lengths thicker than 10ga will reduce power losses. Welding cable (very flexible- many strands) would be excellent and certainly no more expensive than those rip-off gold plated 'monster cables'. At audible frequencies plating conductors with silver or gold has negligible effect. Only at rf frequencies is this needed to reduce losses. Twisted-pair are not fine enough to achieve what good quality zip cord can in this application. And '75 ohm characteristic impedance' has nothing to do with power transmission. Sorry to but in here, but there is a certain quantity of ******** in the above. Multiple strands have no effect whatsoever if they are in electrical contact. A 3/8" diameter welding cable is essentially identical in impedance to a solid cable of identical cross section. The only way to get multiple strands to give you an advantage with skin effect is to insulate them from each other and to regularly transpose the conductors so that each one ends up with the same impedance from end to end. I believe Bob Pease suggests the same thing. He said that *if* skin effect is an audible issue with speaker cables, you should take a 40 or 50 conductor ribbon cable and use the even conductors for one channel and the odd conductors for the other. I don't think he thought it would make any difference, but if you wanted to do something correct from a physics point of view that would be the best way. Why dont you just get some two inch soft copper tubing and cover it with a hose? The reason *I* don't do it is because I know it won't make any difference to my 53-year-old ears. Zip cord works fine. As to anyone else, do it if it makes you feel good. Put Slick 50 in your engine while you're at it... For my hearing a boom box is more than enough. John |
#126
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john wrote:
Jim Stewart wrote: john wrote: Jim Stewart wrote: Mark Rand wrote: On 13 Mar 2005 00:48:06 GMT, wrote: For hi-fi speaker wire the 10ga zipcord offers dozens of strands per conductor, thus it has much greater surface area per unit length than solid conductor would. And THIS is what you want in order to conduct the higher audio frequencies, as they travel along the 'skin' of a conductor. More surface area=more skin. For longer lengths thicker than 10ga will reduce power losses. Welding cable (very flexible- many strands) would be excellent and certainly no more expensive than those rip-off gold plated 'monster cables'. At audible frequencies plating conductors with silver or gold has negligible effect. Only at rf frequencies is this needed to reduce losses. Twisted-pair are not fine enough to achieve what good quality zip cord can in this application. And '75 ohm characteristic impedance' has nothing to do with power transmission. Sorry to but in here, but there is a certain quantity of ******** in the above. Multiple strands have no effect whatsoever if they are in electrical contact. A 3/8" diameter welding cable is essentially identical in impedance to a solid cable of identical cross section. The only way to get multiple strands to give you an advantage with skin effect is to insulate them from each other and to regularly transpose the conductors so that each one ends up with the same impedance from end to end. I believe Bob Pease suggests the same thing. He said that *if* skin effect is an audible issue with speaker cables, you should take a 40 or 50 conductor ribbon cable and use the even conductors for one channel and the odd conductors for the other. I don't think he thought it would make any difference, but if you wanted to do something correct from a physics point of view that would be the best way. Why dont you just get some two inch soft copper tubing and cover it with a hose? The reason *I* don't do it is because I know it won't make any difference to my 53-year-old ears. Zip cord works fine. As to anyone else, do it if it makes you feel good. Put Slick 50 in your engine while you're at it... For my hearing a boom box is more than enough. I thought so too. OTOH, I've had the privilege of hearing a couple of live performances of Bach over the last couple of months. I always sat in the front row and was astonished at what I heard. There's definitely more and better data at a live performance than on a CD. I know that the speaker wire is not an issue, but I also feel that good amps and speakers are important. |
#127
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On 13 Mar 2005 14:37:17 -0800, jim rozen wrote:
In article , Mark Rand says... Multiple strands have no effect whatsoever if they are in electrical contact. A 3/8" diameter welding cable is essentially identical in impedance to a solid cable of identical cross section. The only way to get multiple strands to give you an advantage with skin effect is to insulate them from each other and to regularly transpose the conductors so that each one ends up with the same impedance from end to end. Umm - yes but. At higher frequencies, the solid wire will have *less* loss. The reason for this is that the stranded cable has multiple contact points between strands, and unless the individual strands are gold plated to eliminate oxide, there will be energy loss at each one of those contact points. It's a skin effect thing, but with a twist. Jim G Mark Rand RTFM |
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