What are better for making pedals? Carbon or metal resistors?

[tddy934]

I'm making a distortion pedal I was wondering if carbon or metal resistors would be better.

Carbon characteristics:A complete range of 1/4W Carbon Film Resistors suitable for most applications. High stability and solid construction ensure a long and stable life. 5% tolerance for the full range from 1R to 10M.

Metal characteristics:A wide range of 1/4W Metal Film Resistors with 1% tolerance, suitable for applications requiring tight tolerances. Highly stable and low noise characteristics, together with low temperature co-efficient makes these resistors ideal for the most demanding applications.

[PRR]

Old-time classic pedals used the very cheapest resistors they could get. And it was good.

Today, carbon-film is the "cheap" resistor, and many times better than what most old pedals had.

[Processaurus]

Metal film resistors are superior performing parts (closer tolerance in values, and lower thermal noise), unarguably, but carbon film resistors are fine for pedals, and I would say, "better", because they are dirt cheap, and more common.  Why are they fine?  Because guitars are so inherently noisy, guitar pedals don't really benefit from the ultra low noise parts the way a mixing board or mic preamp would.  Good analog pedal designers will design circuits to have a manageable noise floor and accept a 5% tolerance on most resistors; A well designed circuit with carbon films could easily be quieter than a poorly designed, similar circuit with metal films.  Caps and pots, anyway, have much worse tolerances, 10%-20% lots of times, and pots are really crummy type of resistor (carbon comp).

If money is no object, though, a collection of metal film resistors couldn't hurt.

[petemoore]

  If it measures the R you need, it's the right one.
  It's probably something else though, try unplugging the source.
  Inspecting and scrutinizing the power supplies.
  cables [probably good]...everything else.
  Perhaps a bit of mileage once in a while for large input resistors with high currents, generally this noise is teeny or can sometimes be designed around.