I built an outboard passive tone circuit to use with my Carvin LB70. As an active bass with the ability to go passive, and without any tone controls in passive mode, I felt the need to do this. It's simply a 250k pot, .047 cap (Orange Drop, only because I already had one), an input jack, and 1/4 in cable sticking out, all encased in a clear plastic round container. You can see the Orange Drop, and it looks way sexy. Cable from bass plugs into container, and the container plugs into bass. I'm pretty proud of what I built, and if I knew how to post a picture, I'm sure all would get a good laugh. It's a huge improvement over no tone control at all, but this thing can go REALLY dark. Almost too dark, but it is adjustable. My question: I think the pots in the bass are 500k, and I know the external is 250k, so is this an ok match, or would using a 500k pot in the tone circuit be a better match?