Whats the challenge?
Is the challengee saying all amps sound the same through his speakers (the Harbeths).
Wow, thats a bold challenge.
'
"Here is a challenge then.
If, in a controlled experiment with all variables accounted for (incl. differences in frequency reponse and within the power range appropriate to the amps) under instantaneous A-B relay switchover, driving any Harbeth speakers, if you can positively identify an amplifier by sound alone, I will give you, FOC, a pair of brand new Harbeth speakers, up to and including a pair of M40.1 in any veneer you fancy"
So the only thing that'll be changed is the amp in a set up and you only have to name correctly which amp is playing, wounder if he'll allow the challenger their music of choice. Thats a good test, but those speakers are too big for me, not to keen on the industrial stands etheir.......
A rotel ra- 1520 and an Audiolab 8200a......