I have one the first ACG pres, which has a filter set for each pickup. It has some pros against the Alembic (lower sweep for the LPF and the treble recovery circuit) but some cons as well (sweep doesn't go as high as the Alembic SI or SII). I had it in my Starfire with DS pickups for quite a while. I really liked the low frequency sounds and the fact that it's made superbly. It's a very quiet circuit and works quite well. However, at the end of the day, I'm not really happy with the fact that the upper end of the low pass filter only goes to 3khz. The Alembics go all the way to 6khz and given that one of the big uses for the filter setup is to adjust the attack of the string, especially with pick playing and slapping, the ACG cuts itself off at the knees. Having the treble recovery control helps, but it's really not the same. 6Khz is essentially the upper end of the frequencies that a bass with round wounds generates, so it makes sense to have the filter reach all the way up there, as part of its beauty is how the resonance reaches into the frequencies below the cutoff point as you adjust the Q. Also, limiting the frequency sweep from 300hz at the low end allows the Alembic circuit to concentrate on the mids and highs and makes it much easier to hone in on just the right frequencies. The ACG control is much more sensitive and harder to find exactly the right frequency.
I also had trouble with the wiring on the ACG. Given that the Starfire controls are so far apart, the ribbon cables were stretched to the max and also required some twisting, so they would pop out of the modules on occasion. Overall, I'm much happier with the Series II controls in my Starfire. However, I'm thinking of dropping the ACG into my Modulus Q6 and seeing how that works out. Should be pretty cool!
At the end of the day, the Superfilter is really the one that is done right. The big thing that makes it so cool (aside from it's wide sweep and different filter types) is being able to blend filtered and direct signals. I talked to John East about trying to do this with the ACG pre and he said it wasn't possible. I did some experiments on my own and confirmed that it was at least beyond my abilities.
There are some good discussions on the filter and pickups threads from this page: [Invalid or Expired Link Removed]
As far as Jack and Phil's filter use goes, I don't think Jack had a full Superfilter setup, so it wasn't hard to keep his tone from running off the rails. Phil, on the other hand, was fairly conservative most of the time with his filter settings, but I've heard some crazy stuff ca. '72-74 that he did with the filters, especially in some of the Phil and Ned adventures. Most of it seems bandpass based. I think it's the Hundred Year Hall release that has some radical filter sounds during the Other One jam. Certainly by going to the bridge pickup, cranking the Q and backing off the filter I can get some of those 1974 Eyes of the World bass solo sounds.
That's a sexy beast!
At this rate I might have to make some myself....
