I was not getting a working handclap and the snare drum did not sound right. The noise circuit test from the build guide was not passing (no noise with the expected amplitude on the output pin of the second 4006BE).
I re-heated all the solder joints in the noise section, no improvement.
The circuit is very simple aside from 3 IC's (that are simple only on the outside

Replacing the 4006BE IC's fixed the problem for me. I got replacements for a good price from this Ebay seller: http://www.ebay.nl/itm/2x-CD4006BE-or-4 ... 1129321934