John Larkin wrote:

On Mon, 08 Oct 2007 09:15:27 -0500, John Fields
wrote:

On Mon, 08 Oct 2007 02:47:07 +0100, Eeyore
wrote:



John Larkin wrote:

With an 8 ohm resistive speaker load, 4 ohms of cable resistance drops
volume by almost 4 dB. 4 ohms of reactance only loses about 1 dB.

I'd be interested to see a real world speaker cable with 4 ohms of either.

---
a 200 foot run of 20 AWG from the civilized world will get the
resistance, but at about 20nF/foot required to get to 4 ohms at
10kHz, it's not likely that most speaker cable will exhibit that
much reactance.



It's not hard to get 10 microhenries per meter with a loose twisted
pair. So a reasonable speaker run, at 20 KHz, can easily hit 4 ohms
inductive reactance. Not that anybody can hear the difference.

One of my customers made some very expensive custom cables. To run a
signal out and back maybe 10 meters, to an NMR coil, they used two
runs of RG-8, with the centers carrying the signals and the shields
grounded. The centers were so far apart, they had something like 15
uH/m, and the cable had more inductance than the load, and an
unreasonable dcr to boot.

I got them to try our home-made coax idea, with the super-thin teflon
insulation. That improved things by 10:1 or something like that.

Why do donkeys bray before they think?


They aren't really braying. The starter motor for their vacuum tube
brain has stripped gears.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida