Anyone know the Yamaha CA2000 Amp?

Hi,

I just bought a vintage Yamaha CA2000 amp and am very impressed with it (got some NS100m speakers with it which are very tight if lacking in the very low frequencies.)

Two questions. When I change the switch from "Normal" to "Class A" the sound starts to break up. This is probably a fault but is it worth fixing? What would I get if the class A was working? At the back there is a "DC"/"Normal" switch which seems to make no difference when I change it. What is it for?

Any suggestions for a small subwoofer for the NS100M speakers? I don't want to lose the lovely precise sound but I do miss the fuller lows of my old bass reflex speakers.

Thanks a bunch! Derek