Today i tried a second hand BF-2B in a music store. To be honest i think it's a faulty product. all it produces is a very faint flanger. i turned the knobs in all possible directions. does anybody have a BF-2B and think it is faint? If it's meant to be I will buy it cuz it was quiete cheap.
I had one and it was anything but faint or subtle. When u turn the knobs all the way up there should be wave-ish sound coming from the cabinet/combo. It could be that they just messed with it internally but it could be worse: when in doubt, leave it alone!
FWIW, a BF-2B might be subtle on the open E-string on a bass, depending on the control settings, but it should be very noticeable on the higher strings (or with a guitar) with the knobs turned up. perhaps someone messed with its internal trim pots?