I'm building up a sound system for our living room using second hand
parts. I would like to keep things as small and unobtrusive as
possible. So far I have a Cyrus II amp - this has outputs for one pair
of speakers (rated at 8 Ohms). My plan is to connect two small
bookshelf speakers like the Tannoy Revolution R1s and add a subwoofer.
The options as far as I can see a

1) connect a passive subwoofer in parallel with the bookshelf speakers
2) connect a passive subwoofer in series with the bookshelf speakers
3) connect a subwoofer with a built in amp

I think 1 risks blowing the amp, 2 could affect the sound quality so
I'm leaning towards 3 but this seems a bit of a waste of the power
available from the Cyrus II. Any opinions?