What pre-amp suits the k8060 as a guitar amp?

I have been building the K8060 and since I will be using it as a guitar amp, I was wondering what is a good pre-amp to use with it? would I have to be looking at one which ran off any specific specs?

Check out: http://www.velleman.eu/distributor/products/view/?id=9209

would I be able to attach a 12V transformer to the K4102 pre-amp rather than the 9V battery?

A regulated 12V adaptor should not be a problem.