I've spent a lot of time with AR products. I currently have a Ref Phono driving early model Ref 600's through a home brew passive Pre. I found this to be even better than the best Pre. I have also trialled both the Hovland and AR Ref Mk II and slightly preferred the AR, but both were veiled in comparison to my Passive setup. Mind you this only works because the Ref Phono has a very low OP impedance and you need a relatively high input impedance in your amps. Of course if you are running CD then that's another factor.
Bottom line? If you can run Passive Pre then you won't regret it, next best in my experience is AR Ref Mk II ...
However, you will get a HUGE improvement going to good tube amps, for starters real, musical, immediate, 3 dimensional sound (I originally had serious class A SS Monoblocks in the system). As good as they are even the AR Ref 600's are only half way to where you need to go but you don't need to spend a fortune (done that). I've modified the heck mine and improved them out of sight. First you need Chokes in your power supplies and then you have to triode strap the output tubes, the difference is day and night. If you want even better sound then you can't beat good DHT triode amps. I personally like 845's. I bought a pair of 2nd hand Chinese amps and rebuilt them (a cheap way out if you have some technical expertise). The power supplies, driver circuit and OP trannies are everything! Good Luck!
Bottom line? If you can run Passive Pre then you won't regret it, next best in my experience is AR Ref Mk II ...
However, you will get a HUGE improvement going to good tube amps, for starters real, musical, immediate, 3 dimensional sound (I originally had serious class A SS Monoblocks in the system). As good as they are even the AR Ref 600's are only half way to where you need to go but you don't need to spend a fortune (done that). I've modified the heck mine and improved them out of sight. First you need Chokes in your power supplies and then you have to triode strap the output tubes, the difference is day and night. If you want even better sound then you can't beat good DHT triode amps. I personally like 845's. I bought a pair of 2nd hand Chinese amps and rebuilt them (a cheap way out if you have some technical expertise). The power supplies, driver circuit and OP trannies are everything! Good Luck!