beginner question about input / output capacitors

[bassk81976]

I was messing around, trying to build the Thing-A-Ma-Bob (here), and i now have a new favorite pedal! I want to put this together tonight, but i'm  going to ask a question first before i make anything permanent: I followed one of the guys idea that replied to the thread, who stripped it down, and end up with this:

input ->capacitor ->LM386 ->output

and i'm in love! I then placed a capacitor between lugs 1 and 8 to bypass the internal gain resister, and this ic is a massively broken-down-wall-of-fuzz effect chip!

However, i know nothing of actually really making pedals, and so i have to ask: by having this simple, 4 item board, am i leaving anything out that's necessary? i don't really understand why there are supposed to be input/output capacitors? Are they necessary? Do i need an output capacitor? Do i even need the input capacitor that i have? Or can the ic chip receive a signal that hasn't been passed through a cap?

[phector2004]

capacitors block DC current

putting DC through a speaker will cause it to "jab" forward like it's got tetanus

capacitors let through AC current

putting AC through a speaker causes it to vibrate back and forward (alternatively, the alternating current makes it alternate)

[Quackzed]

if it sounds good, it is good.
however, it may not play nice with other pedals if you omit the input or output caps. but it may be fine... depends. you can always tack on an output cap if it will help you sleep at night...

[petemoore]

by having this simple, 4 item board, am i leaving anything out that's necessary? i don't really understand why there are supposed to be input/output capacitors? Are they necessary?
 Most inputs have DC blocking input / output capacitors, this is because it is good practice, and you do not want DC applied to signal.
 Do i need an output capacitor?
 What's next might not like DC on the input.
 Do i even need the input capacitor that i have?
 Guitar pickups don't do DC worth a darn..what's before might have DC on it's output [doubtful].
 Or can the ic chip receive a signal that hasn't been passed through a cap?
 Doesn't mind as long as there's no DC passing the input, transormers are expensive alternative [and]...leave the capacitor on there.