Two line sources into one amp

Not a good idea as one source will shunt the other, even if only one is active at a time.

Kal

No. Keep swapping the interconnects, don't try what you're proposing, it won't work well even if the unused component is off or unplugged from the wall. There was another thread about this general question not too long ago that went into some more detail on what Kal says, which you might find in the archives (although I don't know what you'd search under), but anyway that's the deal.

You need an A/B switch or a passive line stage.

A/B swith is what I use to go between HT and tube pre with no passthrough.....good results here.

Continual swapping of your iterconnects will eventually lead to excessive wear and ultimatly the need for replacement (not cheap anymore). I too, recommend a well built "passive" line stage (unity gain, unbuffered and very high quality volume control). I utilize a McCormack TLC-1 Line stage (my 3rd one over the years). It has proven itself to be very transparent, without adding many of the influances of other (active) pre amps. There are others though, that can be had cheaper (than the TLC), and with less selection options. In fact, I spotted (what appeared to be) a well built little passive unit (home made) on the auction, not too many days ago. Passive Pre's (like this one) generally sell fairly cheap, and may suit your needs.

You could very easily pick up an excellent phono amp AND also a hi-end, passive pre amp for the returns on the sale of your Modulus 3A.

Some amps just simply " beg" for a passive pre amp (or, a the very least, direct input). These amplifiers may have inherant tonal qualities (that are so seductive) that any, and all, pe-amp influances will take away from their truth and their individual musical nature.

Tubby