There is a lot of information on the Web on upgrading the Quad 405-2 amp.
Starting with a simple IC substitution through to some quite complex
tweaking.
Has anyone tackled this? What changes are worthwhile? Is it worth it, or
should I just sell my Quad and buy a more recent Rotel or NAD?
I don't currently use the Quad because it lacks transparency but I have a
Cambridge C75 preamp that I would like to put into service.
Hints and tips appreciated.

Stephen