Does anyone use a different cable for the neg run?

I may try grounding elsewhere than at the amp.

No, don't do that. The return current from the speaker will want to find its way back to the circuit ground of the amp, and the consequences of that will not be good.

If you connect the negative speaker leads to the ground of a different component in the system, the return path that will be taken to the amp will be through interconnect cables. That will result in crosstalk between that large return current and the low level signal return currents the interconnects normally carry. Also, the interconnects aren't designed to carry high current. I'm not sure exactly what the net result would be, but I would expect that at best it would be a sonic mess, and at worst there would be a feedback-induced oscillation resulting in damage to the system and to your ears.

If you connect the negative speaker leads to an AC safety ground point instead, the consequences would depend on the internal grounding configuration of the amp and the component it is connected to, but I would not expect that to be healthy either.

Regarding the reasons for the sonic benefits you have noted from the cabling arrangement you are presently using, what you are doing is increasing the inductance of the runs. Putting the same signal through two conductors that are physically joined and in close proximity will result in a higher inductance than having those conductors conducting the same current but in opposite directions (i.e., one conducting signal, the other signal return). Also, a run of Romex inherently has much higher inductance than a run of Nordost of the same length. Also, although it is not particularly relevant to your present configuration, increasing the spacing between conductors carrying signal and return currents will result in increased inductance.

The net effect of increased inductance will be to attenuate the extreme upper treble to a slight degree. Exactly how much will depend on the impedance vs. frequency characteristics of the particular speakers, particularly in the upper treble region.

The results were positive,and the increase in detail, less hash, and more rounded full body images has made a believer out of me.

A slight rolloff in the extreme upper treble region, resulting from increased cable inductance, would seem consistent with a perception of greater body and less hash. Perhaps the increase in perceived detail goes hand in hand with there being less hash.

If you haven't already tried it, btw, an interesting experiment would be to interchange what you are doing with the positive and negative runs, i.e., use the Romex runs for the positive connections, and the Nordhost for the negative connections. I wouldn't be surprised if there isn't much difference from the results you are getting now. I would imagine that a difference would be most likely to occur if a solid state amplifier having both wide bandwidth and a feedback loop were being used, due to differences in the amount of rfi pickup in the cables that might enter the feedback loop.

Regards,
-- Al

Thanks Almarg, I'll switch the cables around and give it a go.

I had contemplated using longer runs of my Romex return wires and running them directly to my panels ground wire, not hard to do as my panel is in my listening room.

This way all grunge would bypass the amplification chain and go right to ground at the panel.
My amp will not self destruct if the speaker wires are disconnected.
If I feel brave in the near future I may try this experiment, but for now I am very pleased with the results of my last"too much time on his hands"experiments.

One thing that has crossed my mind in all of this ,are the add on ground link connectors and the posts from those who find these are an improvement.

The ones that you only add to the neg return of your speakers.

The return to ground as far as I am concerned is a little more complicated than I had always believed it to be and not to be taken for granted.

It plays a bigger role in the final sound of the system that I ever believed it did.

I had contemplated using longer runs of my Romex return wires and running them directly to my panels ground wire, not hard to do as my panel is in my listening room.

This way all grunge would bypass the amplification chain and go right to ground at the panel.
My amp will not self destruct if the speaker wires are disconnected.
If I feel brave in the near future I may try this experiment ...

No, once again I strongly recommend against doing that. What happens when the speaker wires are disconnected from the amplifier has no relevance to what I am saying.

Keep in mind that electric current only flows if there is a complete circuit, from the source to the load and back to the source (the amplifier being the source, in this context). The same amount of current that goes out to the load needs to (and will) come back to the source, regardless of whatever grunge may be riding on it.

In the situation you are considering, the complete circuit would be from the + terminal of the amp to the + terminal of the speaker, then from the - terminal of the speaker to the ground at the panel, then through the AC safety ground wiring to the system, and then via unpredictable paths through the system to the circuit ground of the amp.

If the amp has its AC safety ground and its circuit ground connected directly together, that would be the path the return current would take. What that would amount to is connecting the AC safety ground wiring between the amp and the panel, as well as the wiring from the speaker to the panel, in between (in series with) the connection of the amp to the speaker. At best, that will degrade sonics considerably. But the effects may be much worse than that.

If the amp connects its AC safety ground to its circuit ground via a passive component (a resistor, inductor, or capacitor), and some other component in the system has its circuit ground and AC safety ground connected directly together, or connected together via a lower impedance than in the amp, then most of the return current would find its way back to the amp via that or those other components and their interconnections. Which could very conceivably result in oscillations and/or damage, as I previously indicated.

Regards,
-- Al