The A/D conversion stage is the least of your worries. Please take this to
an appropriate forum. Ripping tapes and LP's is not a professional process,
and your specified needs are to use consumer-level hardware. There are
dozens of forums dedicated to your exact needs, and this isn't one of them.

Perhaps you would be kind enough to direct me to, say, three of these
numerous un-professional forums? I should be quite happy to direct my
requests to more appropriate groups, and I apologize for any distress,
however minor or fleeting, that I may have provoked in your lordship.
Jay