If your preamp has most (or all) of its inputs used when your CDP, T/T, tuner, phono stage, etc, is plugged into it, have you ever tried disconnecting everything other than what's necessary for playing music at the time?

So if you're listening to, say, CD, disconnect the leads that are plugged into your other source inputs...

Doing so, in my experience, improves sound quality and gives a more natural, detailed, and 'focused' sound. Quite often, a lot of the stuff that's plugged into your preamp isn't used regularly so why not maximise the performance of the components that are? The improvement is subtle but in my opinion definitely worthwhile.

Marco.