What is the BEST resistor for audio use

There's nothing wrong with Holcos, and The Parts Connection has the best prices on them that I've seen. If you consider Vishay or Caddock, be aware that there are different types, some very highly regarded, others not. E.g. I was informed by one company president that certain Caddocks aren't much good, though he sees other Caddocks as the best choice for an amplifier upgrade he offers. I have one passive preamp using Shallco switches in which I have tantalum resistors, said to be the ones used in top Audio Note Japan gear. I only need six positions, so the high price didn't kill me. I did very careful comparisons with Holcos, which I like a lot, and liked the tants better--a very "natural" sound, maybe even with tubelike "bloom" compared to metal films. In the end, it's very much a matter of taste. You could do some comparison testing with fixed attenuation networks, as I did before settling on the tants. All you need is two pairs of RCA jacks and four resistors, for such a network.

A great idea from Tom Nice!

If anyone tries his idea I would like to read a report of how various resistors sounded, and in what equipment. Would be a learning experience for everyone.

I second Albert's motion and regret I have neither the skills nor the parts availability to try this!

Perhaps the proper question is what is the best resistor for a particular application. About 10 years ago, a friend constructed three sets of pots for my Crosby modified Spectral DMC 10 preamp, all using 39 position TechLabs silver contact switches, but using three different brands of resistors, Vishay, Holco and Resista. We then substituted them in the preamp, listening to each. The Vishays were clearly the quietest and had the most detail but could sound a little sterile. The Holco's and Resista's both sounded less sterile, but at the expense of some additional noise and loss of low level detail. The Resista's had the best soundstage, particularly with respect to differentiating height (i.e. not everything sounded as if it emanated from the same height), the Vishays were the worst with respect to height. None was perfect.

I agree completely with Fcrowder in that it depends upon the position in the circuit. Fcrowder, please correct me if I'm wrong, but I think your resistor comparison tests were utilizing series-configured resists on the volume controls so you were actually listening to the additive effects of several or many resistors in series. Though I completely agree with your findings as I performed a similar test with my DMC-10Z, I found that the noise contribution from a single Holco, Resista or Caddock as in a ladder-type volume control to be much more satisfying than in the series configuration. The Vishay "metal foil" is still the most transparent for low-level applications, but they simply aren't feasible in high voltage/power applications. The only problem with Holcos are that they don't like high voltages (>150 V) regardless of their specs, and you must be very careful when bending their leads. If the soft-metal caps on the ends of the ceramic tube are distorted, they will become noisey or fail outright. However, even with these cautions, they are still an excellent resistor.
Goodluck with your DIY projects,Dismal. They can be very rewarding.