Best caps for a delay pedal

[gnugear]

So I was messing with the socketed caps in my BYOC delay (adjusting the high end rolloff), and I was popping different caps in and out. I had two of the same value ... one a yellow box and the other a green film type. My ears might be playing tricks on me but I swear the green film caps were smoother sounding. So how is the quality of those yellow caps, and since delay is repeating your original tone, I'm thinking that the higher quality the better. Anyone have experience with different cap types in delay circuits?

[R.G.]

... so one day we're all in the lab working on circuits and the department secretary (yes, it was long enough ago that there *was* a department secretary) walks in to the lab and asks "Hey, guys - what color is a capacitor?"

[hubble]

those yellow avx box caps are as cheap as it gets on mouser, although im not sure quality wise, i like them though. 
but then again i thought the chiclet caps were the cheap ones too? eh who knows

[hubble]

heres a link, as there are many discussions about caps i'd assume
http://www.diystompboxes.com/smfforum/index.php?topic=54079.0

[slideman82]

I tried some ceramic caps known as "plate" here in Argentina, just for small values (560p for example) in my Rebote Delay try, ut then switched to polyester "multilayer" (those little yellow ones) and, supposing they were better, they weren't! More distortion was present...