A400 - in mint condition, or as near as, around £100-125.
A300R - not sure about cost, of the two the A400 is pretty special, though the modded A300 Precision (I think it is) by Tom Evans is pretty good by all accounts.
Since gone down the mini system route. Perhaps its just time playing tricks on me but I always remember that amp as being specail.
Think I sold it for about 20 quid in local paper.
So now think I'll go back for another one. Do you think it'll go with Roksan Kandy KC-1 CDP ?
Also, remember hearing (not with the A400) a pair of Linn Index II and thinking when I can afford it I'm going to get those. Never did. But might now ????
The A400 won a lot of plaudits in its day. Couldn't say how well it would go with the Kandy source or Index speakers (never heard them alas!). Can you do some reading up and work out how all three would work together?