If you happen to have one kicking around and want to mess with it, I've been tweaking the values of some of the resistors. Mainly to tame the overdrive back so that it is only slightly dirty (essentially a booster) at the lowest gain.
R15 swap the 10k resistor for 100k
R18 swap the 15k for 33k
R17 swap the 56k for 15k
R14 swap 6k8 for 10k
R15 swap 10k for 18k
I've done this to both the BSD's that are on my boards and I like the sound more.
Drive to minimum and level to max is a nice subtle boost.
Drive and level both set to noon is a nice overdrive.