I've been kind of thinking about building a preamp. Here are the problems. Firstly I'd like to be able to add a digital display eventually maybe the TPA one whenever they get it together or what not. Secondly I'd like to be able to do 2.1 I'd like to try and have a sub output and I'm really not sure how to do it. So this is what I'm looking for tube or solid state and not horribly expensive. My amps right now is a ChipAmp but will probably soon be switching to the Ref RevC. Source is a TPA Opus DAC with USB and SPDIF inputs. Not really sure what other input you guys think I should include?