Hookup wire for tube amplifier?

Ralph, I believe Cardas draws their ultra pure wire in inert atmosphere (nitrogen I think) to prevent oxidation. I don't know what process is used during drawing for OCC wire. But the oxidation will affect only the outermost layer of the wire, correct? Not the internal portion of the wire.

I agree about having good soldering skills. Some advocate tinning the two wires separately before soldering them together. Others advocate making a good mechanical contact (eg, twisting two wires together) before soldering. Any opinions on this? Any useful links would be appreciated.

As for solder itself, people who have extensive experience and done research into this subject advocate eutectic solder containing the same metal as the wire being soldered together. So a silver solder should be used to solder two silver wire together. However, what do you use when soldering silver and copper wire together. Solder containing both silver and copper? Cardas has quad and tri eutectic solder containing silver and copper, as do nonaudiophile solders I'm sure. I've also seen solder containing copper without silver, which I would think would be ideal for soldering copper to copper.

Correction, Cardas use reducing atmosphere (H+) to prevent oxidation. This would be better than drawing in nitrogen atmophere, as H+ will actually scavenge oxygen. Not sure when Cardas applies the insulation or enamel during this process. I'm not in any way trying to support or affiliated with Cardas, as I have never used any of their wire.

I have been voicing my homebrew 91a 300b amp for the past 10 months. I built the initial breadboard with Radio Shack 18 gauge solid core "mystery" wire and the amp sounded just fine. Now that the amp is kinda of finished I am still voicing it. The most influential change was the wire from the attenuator to the 6C6 grid which is now 22 gauge silver. Unisulated. Very open and airy. After much trial this is where I have landed. In the places where higher voltage is being carried, I use 16 gauge copper or silver. The ground bus is also solid core thick copper. I tried 22 gauge silver in the bypass circuits and the sound lost body and low end power. My silver wire is Cardas from Percy and OCC copper from Partsconnexion.

Wire and joints require burn in time. When I make a change I live with it for a month or so and sometimes longer, listening to my music collection and appreciating the good and not so good. I built a cap wire burner with a 12v filament tranny and put wire, resistors, or caps on this burner for a week before putting it in the amp.

When soldering use a good Wellar gun. When you heat the connection do it very quickly use a minimum amount of solder and once the connection is soldered none of the connections should move. They need to stay perfectly still to avoid a cold joint.

The biggest change I made in this amp had nothing to do with wire. I pulled the 6C6 coupling cap and this decreased gain and greatly decreased distortion. The sound opened up in the mids and in the frequency extremes. If you are building your own, try different things and live with them and enjoy the journey.