I wouldn't use any wirewound resistors, not even in the power supply. Non-inductive resistors don't cost much more and are closer to being purely resistive. You can buy them from Mills or Ohmite (Audio Gold) and even the Dayton non-inductive resistors are pretty good. So go with one of these brands for the resistors larger than 1 watt.For the smaller wattage parts, get Tantalum Nitride film resistors if you can. You'll find them from manufacturers such as IRC, Shinkoh (out of production) or Audio Note. Less expensive, more readily available components can be found using carbon film or metal film or foil technologies. Good brands for these are Riken Ohm, Allen-Bradley, Vishay and Holco.