biwire as single wire

You need to be aware of the inductance and capacitance requirements of your amp, as two sets of cables acting as one will change this significantly.

This suggests you may have a combined “biwire” cable. If you do, you could try it, but the inductance may be only about half* that of the individual cables (meaning that for Naim power amps you need the inductance of the individual cables to be at least 7μH*).

*subject to any inter-cable inductance effect, which would best be checked with the cable manufacturer, or measure the inductance of the combined cable.

ChrisSU posted:

You need to be aware of the inductance and capacitance requirements of your amp, as two sets of cables acting as one will change this significantly.

And yet different cables have different cross-section, strand count and surface.  So why would two cables of the same type in parallel be so different to choosing a cable with a thicker, and more containing strands, core?

Frankly if an amplifier is so sensitive to the cable properties you mention that few of us understand exactly and fewer can measure, then cables should only be available in one length and possibly supplied with the unit.  They aren’t, but I would suggest only using half the bi-wire cable (but for goodness sake make sure you double check which half!), or selling them and buying something simpler to use, i.e. a single run.

Judge posted:

ChrisSU posted:

You need to be aware of the inductance and capacitance requirements of your amp, as two sets of cables acting as one will change this significantly.

And yet different cables have different cross-section, strand count and surface.  So why would two cables of the same type in parallel be so different to choosing a cable with a thicker, and more containing strands, core?

Frankly if an amplifier is so sensitive to the cable properties you mention that few of us understand exactly and fewer can measure, then cables should only be available in one length and possibly supplied with the unit.  They aren’t, but I would suggest only using half the bi-wire cable (but for goodness sake make sure you double check which half!), or selling them and buying something simpler to use, i.e. a single run.

Think of parallelled bi-wire vs single cable of the pair as simply being different cables, with different characteristics.  The reason for the difference is that each cable has its own inductance and capacitance, and when you use two in parallel The capacitance increases and inductance decreases. Ignoring any inter-cable interaction, C = C1+C2, i.e. C doubles, and 1/i = 1/i1+1/i2, i.e. i halves (using small i for inductance to distinguish it clearly from the number 1).

with a twin bi-wire cable AFAIK the pair should be identical, so if younonly use one it doesn’t matter which you use.

Ah, thank you.  That is helpful.  I understand from that, if I can manage to express it correctly, that a single cable’s physical (diameter, material etc.) attributes bestow electrical properties, but those electrical properties can be modified by circuit configuration like two runs of the same cable in parallel, as would result here.  A single cable with the same total cross section area, would then have its own electrical properties, different to its skinnier version as well as the double-run configuration.

Essentially, yes.

 The far best results I got was by using a double run connected to amplifier but not connecting them to speakers. Increase was epic. So a double run of A5 of 8m both connected to 500 but only a single pair connected to Magico loudspeakers. Do not know why but this change was so immense, crazy...

So one end is resulting in an open circuit then and doing nothing (don’t let the plugs touch).  That actually means you are only using one half of each pair, i.e. they are now effectively single runs.

I think what you have discovered is what some us may already believe, and that is the resulting sound is more coherent with single speaker runs and so sounds better.  Perhaps it is also due to the capacitance and inductance changes affecting your amp too?

In a previous hifi I bi-amped, but became less convinced by that and when I moved back to a stereo base (instead of AV receiver/multi-amp base), decided to keep it simple and haven’t looked back, because it just sounds better.  I have Neat speakers and bi-wire/amp terminals are a special order, as I understand it, for the same reason.

Indeed it is effectively a single run but the additional cable, connected only to the amp but not to loudspeaker or connectors of the other cable pair, increase sound performance substantially. The amp becomes so much more at ease, powerful, detailed. Really another level. Just try it..

In simplistic terms, an additional cable with both conductors connected to the amp speaker output and the other ends free will add the capacitance of the second cable to the first. In practice, depending on the geometry of the bi-wire cable, it will probably be a bit more complicated due to interaction between the two pairs (which may be different if the ‘polarity’ of the second cable is reversed relative to the first).

100% IB - its adding capacitance.  A capacitor is a just like two parallel open ended wires,  only with a capacitor the wire is made of alloy foil each separated with a dielectric (insulator) & rolled into a cylinder shape.       

However if ERICE thinks it sound better,  OK,  no probs,  I would be more concerned about halving the inductance,  but the extra capacitance is probably nothing in amp performance terms,  NACA5 is 16pF/m,  typical twisted pairs like Chord will be around 50 to 70pF/m,   compare that to the weave/plait types that are where the older Naim amps start to object & they are in the hundreds pF/m,   I've measured RA's 8PR at 295pF/m 

Erice,  what amp & cable do you have??

Mike, he's already said

8M runs of NAC A5.

So he adding 120pF of capacitance in parallel (with a small amount of inductance forming a HF tuned circuit that's probably of little or no consequence given the effect of the open end on the Q of the circuit).

Just so Huge, as I said  the extra capacitance is probably nothing in amp performance terms.   

But ........  thinks,  as in goonshow'ish bluebottle thinks,  isn't a section of open ended wire one of the features/principles of the Chord ARAY design ??

it is bit like shielding but connected only to the source without having the negatives of a total shielding. 

I tried it also with other "passive " cables than NAC a5 and still same result. 

If that is so, it strikes me as essentially an example of an oily steam distillate from one or more Serpentes species.

The effect (beneficial, neutral or detrimental, and to what degree and in what way), would vary randomly depending on the amplifier(s) to which it is connected, the precise nature of the cable and the actual length of the cable attached.  Without knowing the precise circuit detail of the connected amplifier(s), it would be completely impossible to predictable the effect, and even with that detail, prediction of the effect is still far from certain!

EricE posted:

it is bit like shielding but connected only to the source without having the negatives of a total shielding. 

I tried it also with other "passive " cables than NAC a5 and still same result. 

I think what you're trying to describe there is the 'pseudo-balanced' cable configuration, however the 'wire' that's connected at one end only has to take the form of a shield (i.e. enclosing the signal conductors) for this to have any effect.  This is a very well known way of building cables; for audio cables, I use it quite frequently.