Here’s a little added blurb from Garry, the designer/maker of the F Bass preamp. Lots of people are fans of this awesome preamp – fascinating stuff!
“Another unique feature of the preamp is the utilization of a “multiplying” EQ, as opposed to the more conventional cut/boost type. The signal passes through all bands in a single path, resulting in lower distortion, tighter correlation and improved definition, while enabling a wide range of sonic possibilities. Gradually boosting the mid band, for example, while the lows are already boosted, results in a smooth higher frequency focus, while not diminishing the power in the low band. This is partially due to the bandwidth designation of each band, which further lends to a more natural sounding preamp.
Things get more exciting when treble is dialed into the mix. The treble band on the standard preamp is designed to add sparkle, without engaging the more “nasal” upper mid-band tones.”