Whats the difference between 18 and 9 volts? Both my Legends are passive, but already have active Pres, which i believe are EMGs.
The difference is headroom. You will not notice a tremendous difference in tone, especially if you're like me and you leave your EQ mostly flat with a very slight boost or cut here & there. It will sound cleaner, I guess, for lack of a better term. Its not a difference your audience will ever notice, but you probably will.
As far as preamps go, you can buy a pre-wired harness for the Aguilar OBP-3 with the bass/treble stacked on one pot and the mids on another pot, which is a push/pull pot for the mid-shift. That plus volume and blend = 4 pots...no drilling. I have a friend with an OBP-3 installed on his Peavey Cirrus and he likes the tone a lot, but says that preamp is a battery eater. I have a EMG BQC installed on my Spector, wired to 18 volts, and I change the batteries twice a year for preventive reasons, but I've never noticed a dying battery. In fact, usually the batteries I pull out of my Spector have quite a bit of life left in them, but I'm too afraid to have them die on me mid-gig. So, the BQCs batteries last through at least 6 months of heavy use IME.
Both the BQC and the OBP-3 are great sounding and very flexible preamps, you would probably be very happy with either one. The BQC is EMG's highest-end preamp, even if the pre in your Legends are EMGs, the BQC would probably still be a big upgrade to what is in the Legends.
