Been having a gander around for a new pre-amp for my setup and have come across a few passive pre-amps. So I gather they're unpowered and basically a very clean source switch. Worth checking out? Have seen an old Mod Squad Line Drive local to me for a ton - bit much or a good price? Reckon it'll sit well behind my C.A. P500 power amp? Have also seen a couple of Creek passive pre-amps too.