Has anyone else done this? Thought I'd share: I have an Alembic Essence, it's been a staple for quite some time. I was always kind of bummed by how the single low pass filter on the bass EQ'd the bass...as soon as you started boosting highs, you were cutting lows and vice versa. First experiment a few years ago was to replace the low pass with an EMG BTC. Lost a ton of gain because the EMG circuit doesn't boost, it only EQ's. The sound was more functional, but it didn't seem to cover nearly the same frequency range that the low pass could tweak...and the sound was never really that good. Yesterday I resurrected the project by having a Bart NTBT installed in place of tht BTC, and had it ran off 18v. It's miraculous. You wouldn't believe how well the Alembic pickuos and the NTBT go together...it sounds like an Alembic, but much more versatile and flexible. I've also got plenty of output. I really recommend this mod to anyone looking for some new sounds out of their single-filtered Alembic. I think it's really going to reinvent the instrument for me.