rshuck: Thanks for your comments. I am just trying to find the time to finish off the matching speakers now, and then I can have a proper critique... Then put the subs together...
(1) The signal paths from the cd63 digi out is long, but I deliberateley placed the dac where it is, so that when I add a Tentlabs clock, the path will be as short as possible. The rest is nearly as short as possible. I suppose that the amp could be closer to the passive pre, but I am thinking of adding a gain stage preamp there, if the output from the Fostex FE127E (91db) is not sufficient.
(2) I had not thought of this. It is a nice idea. You would need larger knobs than the ones I am using. Mine have a very "cute" feel to them. Some bits have to look a bit DIY otherwise no one will believe that I built this.
(3) Agreed. I will try aluminium first. Doing it in wood would not be hard as the drawer hole is exactly the same width as the 24mm ply. The laminates could even line up.
I will keep an eye out for an aluminium or silver metal mains switch also.