This is a clone of the Maestro Bass Brass Master BB-1.

I started with RG Keen’s layout of this circuit, and made a couple of minor changes. First, I wanted to be able to mount the pots directly to the PCB, as pictured below. Second, I wanted to wire the switching for the filter section as in the schematic (link above).

To my ears, this stock clone sounds good on both bass and guitar. However, the filter switch (Brass1/Brass2) doesn’t seem to have much affect. Others who have done the wiring as in RG’s layout have reported the same. It could likely be made more responsive by simply adjusting some of the component values (resistors) in the filter network.

NOTE: The schematic in the link, above, is the corrected version.