At what distance are balanced XLR cables needed?

Kijanki, yes, I think I can. The purity of metal has a lot to do with 'diode effects' in the material. The idea is that strands of wire do not conduct completely linearly- they are affected by diode junctions that exist between them.

However these diode junctions are not very profound or robust. They would only be detectable (if you will pardon the pun) if you had very low currents in the cable.

Well my friends, this will be the case with most single-ended connections, and for that matter any connection of high impedance.

OTOH, if we are using a balanced system *that conforms to the balanced standard* then there *will* be significant currents, and any primitive diode junctions will be of no account.

Now I should point something out. If anyone tells you that they have more than 99.99% purity of metals in the wire, they are likely pulling your leg. Oxidation makes it virtually impossible to exceed this figure!

Additionally, OFC (99.99% pure copper) was *not* developed for audiophiles, it was developed for alternators and generators because it is more flexible. However, a few weeks after extrusion into the insulation, there will have been enough oxygen contamination of OFC so that, other than flexibility, it will have about the same characteristics and purity as regular ETP copper.

I would suspect that bigger current would cause bigger voltage drops on said junctions (or impurities) everything else being equal.

600ohm must be not very common since I've never seen anything that can drive 600ohm without distortion. For now I will stay with my Acoustic Zen Absolute XLR (7N silver, 0.02uH/ft, 6pF/ft). Acoustic Zen as well as Audioquest and many others must believe that metal makes a difference since they use 99.99999% pure copper and silver.

Kijanki... 600 ohms is the output impedance of the preamp. You don't have to drive 600 ohms.

200K is the input impedance of Atmasphere power amps.

Acoustic Zen as well as Audioquest and many others must believe that metal makes a difference since they use 99.99999% pure copper and silver.

It makes a difference in what they can charge for the product, that much appears to be true.

Eldartford, 600ohm is output impedance and 600ohm is input impedance of power amp. Because of 2 to 1 division of the voltage output voltage of the driver (driving 1.2k total) has to be 2x higher - being equivalent to nominal signal driving 600ohms. Even if gain increase is on the power amp side driving 1.2k is not easy. Many preamps have hard time with 10x that. For instance Rowland in my 102 power amp uses additional amp just to increase input impedance from 10k to 40k.

"It makes a difference in what they can charge for the product, that much appears to be true."

Drubin, Absolutely - but on the other hand nothing suppose to make audible difference, according to calculations, but this cable is way better than very decent AQ King Cobra I had before (and it is only 0.5m XLR). What make clarity so much better? Dielectric? Metal? Who knows. I think Acoustic Zen knows (and they charge an arm and a leg for that).