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Cable Asylum Interconnects, speaker wire, power cords. Ask the Cable Guys. |
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Cable Asylum Interconnects, speaker wire, power cords. Ask the Cable Guys. |
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In Reply to: Question for John Risch posted by Joe S on February 17, 2000 at 07:20:51:
I have heard of driven shielding, where the shield is fed a signal that is the same as the hot wire signal, and the net reuslt is the effective capacitance of the cable is lowered. If the driven shield is driven from a low impedance source, which is low impedance up into the RF range (whether due to a brute force RF capable amp, or a cap to ground), the it can actually increase shield effectiveness. I believe this is the Synergistic
calls DIscrete Shielding, although they don't come out and directly say it.Concerning placing DC on a shield, if this is an electrostatic connection, like the driven shield, then it is remotely possible that there is some sort of dielectric 'bias' being incurred. that is, the dielectric within the cable would be biased to a single-ended center point with respect to the audio signal it was carrying. This has been shown to lower distortion for electrolytic capacitors, see:
http://www.capacitors.com/pickcap/pickcap.htm
for more info on this effect.
See Fig. 1, portion d, e and f. and relevant text.I suppose it is possible to bias even a quality dielectric such as teflon, and the main benefit would be to effectively keep it from reversing polarity, sort of like operating the dielectric single-ended.
Hey, a SET-type interconnect !For those that want to try this at home, it could easily be done using a 9 volt battery if you have a telescoped shield, that is, a twisted pair with overall shield. Lift the source end ground from the overall shield, and attach the 9 volt battery in series. Theoretically it shouldn't matter which polarity it was, however, in practice, it may. Then bypass the battery with a medium largeish high quality cap, say around 0.1 to 1 uF. It will be difficult, if not impossible to shield these components, unless they are placed inside the chassis, or inside a grounded box, and the connection to the cable RCA plug made via a small coaxial cable of high quality. The cap will keep the ground connection low Z until the battery can kick-in. It could be a much larger cap size, especially if there is any hum or interference problems with this hookup. The battery will last for beyond the normal shelf life rating of the battery, as it will be primarily operating in an open circuit mode. Each cable would need this to be done to it independantly. I would make the polarity of all the cables the same, to avoid any possiblity that the shields would short out against each other. Remember, with a telescoped shiled, the source end will have the battery connection to the source ground, and the load end of the shield will be left electrically floating.
This will put a DC voltage of 9 volts on the shield, and 'bias' both the ground and hot wires dielectric with respect to ground, effectively operating the dielectric's of each wire single-ended.
Again, in theory, this would benefit the lesser dielectrics more than the better ones, but they should all respond to this single-ended operation, and the result I would predict would be an improvement in the bass and secondarily the midrange region. Busy music would benefit the most, and gain clarity.
Just like attaching new cables, there would be the potential for a break-in period, where the dielectreic would settle-in around this new bias point, and reach it's full sonic potential in a matter of days, or perhaps a bit longer.
I will try this one myself as soon as time permits (may be weeks), so if any one has some homemade twisted pairs they can experiment with, post your results.
Also see:
http://www.synergisticresearch.com/new-technology.htmJon Risch
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Follow Ups
- Re: Question for John Risch - Jon Risch 18:47:23 02/17/00 (2)
- Re: Question for John Risch - Joe S 14:37:54 02/18/00 (0)
- thanks! - Joe S 14:21:14 02/18/00 (0)
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