Cross-connected dual coaxial speaker cables

[Jazzman53]

As a general rule; you can design a cable for either low inductance or low capacitance but you can't have both in the same cable. This cable comes about as close to cheating that rule as any I've seen. I built a pair to drive my ESL speakers. Enjoy!

Link to parts list and build photos: Cross-connected coax speaker cable

A quote by the cable's designer, Jon Risch:
“Cross-connection is used to reduce the inductance to an absolute minimum. Merely paralleling the center wire and shield would create two separated different polarity composite conductors with an inductance much higher than the cross-connected pair.”

 

[Speedskater]

As a general rule; you can design a cable for either low inductance or low capacitance but you can't have both in the same cable. This cable comes about as close to cheating that rule as any I've seen.

No it doesn't!
There is no realistic way to to cheat the rule.
But on the other hand or some legacy or boutique amplifiers care about a little added capacitance.
And only those few loudspeakers that have a low impedance at high frequencies care about the loop inductance of the speaker cables.
For those loudspeakers, just place the power amplifiers near the speakers and use long interconnect cables.

* * * * * * * * *
Stop reading Jon Risch, he will just waste your time with bad ideas.

 

[DonH56]

I don't follow that... Cross-coupling in that case does not change the impedance, though it does change the current paths. I'll have to think on it more (but probably won't). Here is a quick simulation of the two cases. Circuit 1 is just two coaxes in parallel, and circuit 2 is when they are cross-coupled. I used LTSpice so anyone can do the same thing. I used the coax parameters from the linked website; O1-O4 are coaxes (modeled as lossy transmission lines). Note coax generally has higher capacitance than basic twin-lead, and cross-coupling as described defeats the shielding properties coax provides. Must be missing something but lunch time's over. - Don

 

[Mrjome80]

I don't follow that... Cross-coupling in that case does not change the impedance, though it does change the current paths. I'll have to think on it more (but probably won't). Here is a quick simulation of the two cases. Circuit 1 is just two coaxes in parallel, and circuit 2 is when they are cross-coupled. I used LTSpice so anyone can do the same thing. I used the coax parameters from the linked website; O1-O4 are coaxes (modeled as lossy transmission lines). Note coax generally has higher capacitance than basic twin-lead, and cross-coupling as described defeats the shielding properties coax provides. Must be missing something but lunch time's over. - Don

View attachment 26590

View attachment 26591

Sorry, but if you connect GND on both sides, this is not a correct simulation. Speaker side has to be "floating" ;-)