Oh, how your Katans should sing active with a c4100! Still I believe you will have to buy new aktive modules (the Chakra series can't use the old stereo cards), so you'll need to factor this into your price.
As for preapms, the Kolektor is usually a great buy on the used market (though you should never pay over $500 for one). The line stage on these is awesome for the money. That said, a used Kairn with slimline power supply (be aware these came in three different versions, and the last with the slimeline sounds much better)can be had with patient shopping for around $850 to $1100. These are substantially better than a Kolector. For the best buy still, look for a AV 5103. This is actually a surround processor that was also Linn's reference audio preamp until the advent of the Klimax Kontrol. There is one of these for sale right now for $1300. Originally these were like $8500, but since they are part of the video world where they are out dated, their price has dropped like a rock. Hope this helps.
