Has anybody tried using single solid core cables?

Ozzy, your onto the real deal. I agree with your findings based on recent endeavors.

With the exception of my interconnects (copper/silver alloy, stranded) my power and speaker cables use solid core conductors.

The power cables are ~15 gauge DIY Home Depot-style solid core wires, twisted and non-shielded. These are connected sans powerstrip so that the respective conductor-ends (lead, return and ground wire) are tightened directly to each other via screw terminals.

Speaker cables are Mundorf's ~15 gauge Silver/gold (99% silver; 1% gold) solid core wires, teflon insulated, and tightly spaced in a pure cotton outer sleeve. As an on/off experiment these are connected in (single-wire) parallel mode with Mundorf copper foil coil-"wires" (28*0.07mm = ~14 gauge), with the foils more loosely spaced.

A friend gave me this tip, and while initially I was somewhat reluctant into following his advice - for no other reason really than ill-based skepticism (I'm no "techie") - I must say this combination of copper foil and silver/gold wire offers a very satisfying result as well. Compared to the silver/gold wires alone leading edges here seem sharper, less smeared; low end appears better integrated and more coherent, likely because of better very low end control and mid bass energy; mids have slightly more texture, fullness and presence, and the highs are a bit smoother with more substance.

Overall the sense of quickness, coherency, lack of smear, and presence/texture is more outspoken - in a sense a more intimate presentation, but without the soundstage being restricted as such.

I'd be very interested in knowing from others who've experimented with parallel speaker cable runs in single-wire configuration (solid core, preferably :)), particularly with different conductor materials and/or overall cable geometry.

From the perspective of wire directionality, how many high end cable manufacturers are there that mark their solid core cables with directional arrows? Part 2 - are there any manufacturers of stranded cables that mark their cables with directional arrows? Or would that be expecting too much, keeping track of the proper direction of all the various strands?

Try hooking your cables up backwards...all hell breaks loose, the cat explodes, and music becomes an unlistenable heap of cacophony rendering the listener on the floor curled into the fetal position wimpering, "stop, please stop."

No one has mentioned that the insulator or dialectic material is as important as the conductor.

I purchased couple of feet of 16 awg, OCC copper, SOLID CORE, Neotech hook up wire with Teflon jacket from Parts Connexion and silk tubing to conduct an experiment on my Cronus Magnum.

The cronus uses pvc jacketed, multi-stranded wire throughout the amp's power distribution. I switched the wires going from the IEC inlet to the fuse and from the fuse to the amp's circuit board with the newly purchased, teflon jacketed, solid core, Neotech wire. There was no doubt that the sound had changed when I first listened with the new wire. The teflon tremendously colored the sound. All natural dynamics and tonality that I previously had was lost. The sound stage shrunk in width and extended deeper in depth. The imaging gained focus and layering. Teflon caps have a burn in period of 450 hours but there was no way I could wait that long for these cables to "burn in".

I listened with the teflon wire for a week then I stripped off the teflon and replaced it with the silk tubing. Again, there was an immediate change in sound. The OEM sound returned. The original naturalness and dynamics was present. I decided to leave the wire alone and I did not listen to the stock wire vs. the silk insulated solid core wire.

Keep in mind that these differences were noticed from wire that wasn't even in the signal path.

For those of you who heard differences in solid core vs. multi-stranded wires: were the insulators made of identical materials between the 2 types of wires?