Re: 2-channel listening
I don't think Alon quite understood the question.
The answer is, maybe. You don't necessarily need a pre-amp, but you DO need a volume control, though you probably have that with the computer. Also, there can be impedance and buffering problems when you skip the pre-amp. How do you know? I'm not sure, but here's my experience with it.
Several years ago, I did a similar thing. I was using a Nakamichi CD player which had a variable output that was controllable with the remote. I fed it straight into an Adcom power amp, no pre-amp or switching. It sounded fantastic. I also tried it with a Forte pure class-a amp with the same outstanding results. Later I replaced the Adcom with an Aragon amp, but found the Nakamichi couldn't "drive" the Aragon's input, and ended up with very thin sound. By then, digital surround was arriving, so I wanted a pre-amp anyway and ditched the more direct system.
EDIT: I forgot. There have been (and maybe still are) items like a pre-amp, without the amp. They don't actually amplify the signal, but they buffer it to reduce or eliminate incompatibilities and have a volume control, essentially resulting in what you are looking for (maximum sound quality), with more flexibility. I seem to recall Adcom made at least one of these "passive" pre-amps. Yeah, that is a contradiction in terms, but I don't know what else to call it. Actually, Aragon might have made one.