A British magazine called (I think) Hi-Fi World has been doing an ongoing series on building a modern version of the A 25. The writer's been using an original A25 as his ongoing A-B reference. The magazine also has ads for someone selling a kit version of this "modern" A25. You might want to get the latest issue and e-mail the author of the article. He's certainly worked with the design enough to have a feel for its strengths and weaknesses.
Good Luck
Marty
Good Luck
Marty