My metal vs. carbon resistor shootout.

[skiraly017]

Curiosity got the better of me so I built two LPB-1 pedals, one with metal film and with carbon film. The only difference I heard was the metal film LPB-1 was slightly (and I do mean slightly, almost unnoticeable) "clearer" sounding. That's the only word I can think of to describe it and it certainly wasn't enough of a difference to push me one way or the other. I'll use whatever's available and not make myself crazy over it.

[Connoisseur of Distortion]

post samples. don't say which one is which. let's settle this. 

actually, i'm just a bit interested to hear the difference

[Skreddy]

The best shootout would be a BMP instead of LPB1. 

Two reasons: 1; more resistors=more of a cumulative difference, 2; because the BMP generates so much high-frequency distortion and so much gain, and this is where "smoother" sounding parts will be most noticeable compared to "clearer" sounding parts.

If you build two BMPs, one with cc and one with metal film, use either Central brand 2N5088's (Mouser # 610-2N5088) or Fairchild BC249C's (Mouser # 512-BC239C) for close consistency between transistor units. 

NOS transistors are super inconsistent, but a good test could be done by socketing them and using the same transistors between the test units.