So far I've constructed a prototype to see if my ideas would work out.  The amp was put together because I had a box of NOS 807's and 1625's sitting in the garage.  Unfortunately, the project hasn't been that successful because I haven't found an appropriate power transformer.  The resulting B+ is about 380VDC which causes the 1625's screens to arc over on powerup!  I found this amp worked OK with conventional speakers, but didn't work well with Quad ESL's and lacked 3D and separation.

This is what the amp currently looks like.  The output transformers are Hammond 1627SE and the output vlaves shown are 1625's with 6SJ7 as drivers.  The rectifier is a 5U4.
Click on the thumbnail to see a larger view of the schematic.

Future Plans

At the moment I'm planning to rebuild the amp using KT88's (which should handle the high B+).  Unfortunately, I am unlikely to do any further work on the amp till next summer (2002/03) due to other commitments.