Bob:
In mono mode, think of the SF-2 as a 3 band mixer. One band is the dry signal, and the other two are the two filtered channels. I start by turning both filtered channels completely off and set my guitar's dry sound the way I like. Then I turn the dry channel on the SF-2 completely off and turn up the A filter channel. I usually set this one in low pass mode and dial in a low freq. tone I like. Then I turn filtered channel A completely off and turn up filtered channel B. I usually set this one either in band pass or high pass mode and fiddle around until I get a high freq. tone I like. Then I turn channel B off. Finally I bring up the dry channel again, then mix in filtered channels A & B to get the final tone I'm looking for. I hope this helps.
Bill, tgo