Which used preamp for Halo A21, under $1,000?


Right now, I have an Anthem TLP-1 pre mated to a new Parasound A21. The combo sounds good, but I suspect that the Anthem may be the limiting factor to achieving "great." Suggestions?

Preamp: Anthem TLP-1
Amp: Parasound Halo A21
Disc player: Oppo BDP-105
Turntable: Beogram 8002
Speakers: Alon II
dbxdx5
I have the Halo A21 as well. After going through several preamps I settled on the TRL Dude. A lot of information about the Dude in Audiogon's forums.