The Fat Boost is more in the RC's category than the AC's. The AC has much more gain than the FB. I've had all three and much prefer the RC Booster to the other 2.
Hi if you want to get a great van hallen 1 sound try a Distortion Pro-B
or a Athana signature distortion'
both of these [edals nail that sound www.effectspedalboutique.com