compatability confusion for newbie, yamaha ca-1010

Yes, exactly. I had a powered sub that also acted as the crossover, so the signal went from amp...to sub...to speakers. You can also check on the active sub w/crossover option if the seperate amp & crossover gets too price for the passive sub.

The 'crossover settings' you refer to relate to the tone controls and not to the separation of signals into bass (sub) and main speakers. You need a separate crossover for that.

HI i own a mint yamaha ca1010 amp. it gave me much listing pleasure for many years untill i brought a rotel pre-amp and a RB991 power amp...
in comparison the yamaha is like listerning in mono ! it has no image what so ever ! What i came to realise is its mostly the preamplifier stage that is the weakest link, there's such a long signal path and so many switches im supprised the signal gets to the power amp at all....
Used with the rotel preamp the power amp stage is quite good though.... :-)Still have the amp in a 70's system in the bedroom which is ok, but not serious listerning...

The Yamaha will actually do 90 + 90 watt rms 20hz-20,000khz at 9 ohms

and 120 + 120 watts rms at 4 ohms

it only does 140 + 140 watt rms at 1000hz at 4 ohms.