I have a B&K Reference 4420 amp that I am very happy with, but it really does run warm when in use. I also noticed that it stays warm if left on all the time. What I need is a preamp with a 12v trigger so that I can control the amp with the pre on/off.

- I don't mind buying used, but I really would like a good sounding preamp (I am replacing a B&K PT3-II preamp, so I'm hoping for something that's an upgrade from that).
- need phono stage
- Some Rotels have a 12v trigger, but I have no idea which models I should focus on.
- A few Adcoms (GTP-502) also have a 12v trigger, but they are hard to come by.
- $400-600 price range (or is that too low?)
- I would prefer to steer clear of tubes and passive preamps - I know they sound better, but tubes run hot and passives seem a little too finecky.

Any other brands/models that come recommended?