Quick capacitor substitution question

[frogman]

I am about to start building a "box of hall reverb" pedal.

http://3.bp.blogspot.com/-S1mac2DalyY/T6OsSIVA9uI/AAAAAAAABa8/jArJBxnw6Fs/s1600/Box+of+Hall+-+culturejam+-+BTDR-2H_B.png

It calls for a 470pf capacitor (bottom right). Does anyone know if I could get away with using 100pf or 220pf without altering the sound of the circuit?

Also isn't there a way to combine their values so I could get 320pf?

[PRR]

Caps in audio circuits are rarely critical. +/-20% is same-thing. +/-50% may be slightly different sound.

Two 220p in parallel is 470p for nearly any practical audio purpose.

[frogman]

I think i am going to combine the 100 and 220pf in parallel, just because I have them in front of me and dont want to order more parts. That would be roughly 70% of 470. I want to wait for at least one more person to chime in for reassurance though.

[R.G.]

I think i am going to combine the 100 and 220pf in parallel, just because I have them in front of me and dont want to order more parts. That would be roughly 70% of 470. I want to wait for at least one more person to chime in for reassurance though.

If you have more than one 100pF:

Parallel 220pF with two 100pF; the parallel total is 420pF nominal (not counting the tolerance ofthe parts)

Now series two 100pF caps: this gives you an equivalent of 50pF nominal.

Parallel the two 100pF series with the 220 and the two 100s in parallel and you have 470pF nominal.

[PRR]

Would be nice to have a schematic. Very-very hard to work out what a part does from a bare layout.

PedalParts has a nice PDF. It *seems* this cap rolls off supersonic sounds before they get into the Brick. The Brick is digytal so supersonics may "alias" into gibberish in the audio band. Direct from guitar, that's probably not a problem. In fact they show an alternate value of 100pFd. So it does not *seem* to be critical.

R.G. tole you how to get nominal 470 on-the-nose.

If you have just two 100pFd, I say 100+100+220 is 470 for *nearly* any practical audio purpose. 12% difference. Two musical semitones. And several octaves higher than guitar harmonics.