Integrated as preamp?

Yes, you can use the integrated as a preamp. If your current set-up sounds great to you ... stop and don't do anything else. Live with this set-up for a few months and begin to identify your likes and dislikes before considering any potential upgrades. This is one way to insure that you get the most out of an upgrade.

Best regards,

Rich

Why not?
My integrated as unbalanced outs. I currently use these outputs to a sub.

Rar1 is giving you excellent advice. Maverick18, I too would advise doing the same. You said:

To my ear, Thiels sound great with this little 50W@8 ohm amp.

Thanks, gentleman. Sage advice. I qualify my comments with great in comparison to the B&Ws. I suspect there is more, particularly on the low end, than my amp delivers.

Or maybe it is just the Thiels expose the limitations of my upstream gear (Rega P1) and (Sony SACD CE595, budget SACD multidisc that has gotten some bang for buck praise).

I have little to quibble with on analog side but some hit and miss with CDs that suddenly sound thin. Clearly, the speakers do expose poor recordings, too, because same songs on different CDs can sound quite different. May I ought to be looking to upgrade CD first.

To confess, the real problem is I have more than offset the cost of Thiels by selling my old stuff (stunning what used Bang & Olufsen cartridges fetch on ebay) so I am surprisingly sitting on a bit of cash and trying to figure best places to start a slow upgrade of rest of system. The amps, from reading other Thiel discussions, sounded like a good start.

I'm gonna think on it a bit.

The situation that you are in is that you have source components that are not in the same league as your speakers and amps. Lots of things that you could do and the CD player would be where I would look first ... but do you spend $600 on the next level up of class beaters like the Music Hall CD25.2 or Cambridge Audio 650C or do you spend twice or three times that amount on something much better and probably more satisfying in the long run? Or if playing records is more your thing, do you drop the same amount on a better turntable?

In thinking about my own progression, I found myself making a number of changes in fairly quick succession and I was never quite happy with the new stuff for all that long. Four 4 years ago, I changed over to tubes and that pretty much did it for me. To appreciably better what I have, I would have to spend truly serious cash and I have no interest in doing that. Ergo, my advice of sitting with what you have until you really identify what is not working for you.

Best regards,

Rich