I recently replaced the electronics in my B40 with a new Carvin active unit with the sweepable mid control (Passive overall volume and blend going into the active board). Sadly, this came at the expense of the option to switch to passive. I miss having that option, and looking at the way it's connected, it doesn't look like it would be too difficult to add a switch to do so. I'm thinking about adding a DPDT switch to switch the signal hot line (coming from the volume pot) between the active board and the output jack and to switch the battery line off when in passive mode (the same way the jack switches it when a cable is plugged in). I drew up some rough schematics of the way it's wired and my idea for modification.
I'm looking for anybody who might be able to warn me of potential pitfalls with this endeavor. One thing that caught my eye in sourcing a switch was that I could get an On-Off-On switch and have a muting function too. Anybody tried anything like this before?