I know that Quads have a reputation for getting along well with lower powered amps but if your 2805s are anything like my 989s, you might want to consider a little more power than 35 or 40 watts. This is just my 2¢ naturally but I've used both a c-j Premier 11A and a Premier 140, and as good as the 70 wpc 11A sounds with the 989s, the 140wpc of the Premier 140 takes the sound to an entirely new level in terms of clarity and dynamics. The sound stage, which was excellent with the 11A, solidifies, is better layered and expands with the higher powered amp.
As I said, just my 2¢.
Good luck with whatever you decide upon, the 2805s are supposed to be one sweet set of speakers.