...What really gets me is why people replace the electronics in Alembics. I've seen a few instances where folks rip out the stock electronics and replace them with something else. In this case, what would EMG's offer that the Series 1 electronics do not offer?
In a word - availability. I'd guess at some point the Series electronics got unmanagably noisy, or just died altogether and this EMG setup was the resulting fix. I'm just glad the bass isn't hacked up too bad. It's actually a pretty slick installation. Faced with a choice of shipping it back to California for a fairly expensive repair, or retrofit with aftermarket actives... it happens, and usually in a much more haphazard fashion. This bass is a pretty easy fix, but not a cheap one... the same problem still exists today - it needs Series electronics, and there's only one place to get them. (lets not even discuss the creep over in Yonkers...)
Like Jazzy says, you could put Signature or Anniversary electronics in there but here's the catch... those old pickup routes are
totally different than the new ones. You'd have to re-rout for even AXY's, which you'd have to do anyway if those original two-tab pickups are dead, if you were going to put Series electronics back, as the modern Series pickups won't fit either. Strictly pre-1976 replacements here, or break out the plunge router.
I'm not personally interested right now, as I already have enough projects going, but definitely watching #75-173 with particular interest.