Thanks John, I like this little boards, perfect to combine with other effects in one box. I think you have a typo, should be 47nF to get 107Hz center frequency.
For anyone who wants to customize this, last year I made an online calculator for this circuit:
http://vulcanofx.blogspot.com.es/p/tilt-eq-calculator.html. The long explanation is
here, but basically you specify your desired center frequency, amount of bass boost and amount of treble boost and it calculates the values of C1, C2 and the 47k and 15k resistors. The amount of bass and treble boost can be asymmetric:
Mark, if you add another rotary switch you can vary the boost values, maybe two asymmetric configurations (one bass heavy and the other treble heavy) and one symmetric. This is starting to sound like an interesting EQ build.