Well I thought I'd just scare you witless by showing you some typical internal pictures of a R2R which I am giving the once over.
The kit of parts came from Nagravox advertised on Ebay. 140+ capacitors of dubious quality
but certainly better than the 20+ year old tantalums and 'other' electrolytics.
Most of the boards come out OK but some of them needs a special note of all the screws and cables.
I was shocked when I looked at the circuit diagram as there is only a single LM317T regulator for the majority of the daughter boards.
The mains transformer looks a decent C core and there are two voltage rails for the entire machine.
How the hell these machines can sound soo good is a mystery to me, if it was a power amp it would be laughed out of the room.
Component quality is errhmmm, basic and functional,
just what it could do with a more refined circuit.......well an outboard valve stage is probably the only way due to the complexity as others have done.
Have a look at the images below to see what a pigs ear of a design...
.........well IMV. Guess that the seperate boards allow quick substitution in the event of a failure.
V