Hookup wire for tube amplifier?

Dracule1, you should try direct-coupling sometime. Especially at the output of a preamp this can have a huge effect.

The issue is break-in and longevity.

Copper seems to take longer to break in than silver does. If handled correctly they both get to the same place.

You have to be careful with silver- don't go with silver-plated copper and you have to be careful to use the right solder too. Silver wire usually has a Teflon insulation.

Copper works fine but you have to be careful with the insulation. Teflon will not block air from the wire, and the wire can't get oxidized! In addition the extrusion process runs at a high temperature so unless very special provisions are made the result will be that Teflon-coated OFC will not be OFC once inside the Teflon.

BTW, there are no wires that have more than 99.99% purity. If more than that is claimed either the supplier is misinformed or they are lying. I remember that there was a craze for '6-nines' copper a few years ago; when it was found out that such a thing does not exist, the various manufacturers that were making such claims quietly stopped doing so.

To retain its OFC status, the insulation has to be able to seal the wire; its helpful if it melts a little near the solderjoint. If it does that correctly it will be fine for decades.

Kijanki, I don't think you will find 7Ns copper in any wires anytime soon. As soon as its extruded you are down to 99.99%. The wires as seen in the article don't seem to be commonly made.

Further, it might be interesting for audiophiles to understand that OFC was not invented for audio reasons. It was invented to improve wire flexibility, for things like brushes in generators and the like.

Dracule1, we have compared silver and copper many times over the last 30 years. So far no-one has been able to come up with a wire that shows a particular advantage for silver or copper- unless you include the break-in time. During the period of break-in silver seems to have an advantage. This is not to say that all wire is created equal though!

If you are soldering silver wire, the most basic form of solder to use is SN62 which is silver bearing. There are more exotic forms of audiophile solders that seem to work fine too. SN96 works too but you need an 800 degree tip which is a real pain, and despite the SN96 being eutectic, it can still crystallize, which isn't supposed to be good from a sonic point of view. The modern lead-free (RoHS) solders seem to work OK in a pinch. If you are working with copper then SN63 is the preferred solder. It has no silver but retains eutectic behaviours.