It's almost done...sort of

[taylorchuck15]

Well, I built the Fooldrive2, but it doesn't work. When the boost is engaged, it's fine. But when the drive is engaged, it just hums really loud, and sometimes you can hear the guitar come through the hum. I did everything in the project right, except for two parts. On the layout it said 1uf NP, but when I ordered them I got polarized 1uf's. Somebody told me that I could still use them if they were in the right direction, so I tried it and he said that if it wasn't getting any sound, I should turn it around, and then see, but thats not working. What should I try next?

[GibsonGM]

Well, 1st make sure the caps are oriented the right way...usually, + will be heading into the effect, and at the output - will be going out, with a negative ground.  Easier to do if you build the project on a breadboard first, for sure! 

1) An unspecified hum, with signal mixed in, makes me suspect that something isn't grounded - so check that all parts (esp. input/output jacks and pots) have the right grounds. If it works in 'boost' and the hum is in 'drive', well, that's the area I would check out first!!  Maybe at the switch for 'drive', too.   In/Out caps should have the same effect regardless of what's going on internally in the ckt. 

2) After that, it's typical that some part WILL be grounded that shouldn't, so I'd look at that next.  See the pattern?  Going back over your work many times until something becomes clear.

LAST I would suspect a fried cap.    Using an audio probe to go thru the thing might also help after visual inspection.

It's all about going over the thing, over and over, until you find the mistake 

[taylorchuck15]

ok. that helps. I will go over my board. over and over again.