Incidentally, I asked Leszek about repairs, etc., and here's his reply:
[quote]The amp is very well built but I wouldn't dare to say that it's indestructible! This is an electronic device assembled from hundreds of pieces, and like any amp there is always a possibility that something might break. Sending schematics to any place in the world is not a problem though. Local amp techs will manage to repair the R-400 easily.[/quote]
Hopefully it'll be a long time before it's needed, but good to know there's nothing 'stealth' going on under the hood.