Leslie 60's have a pretty unique sound - not left behind by newer effects. The effect is created by the Leslie "space generator" which my friend who got mine up and running says is created by motors rotating some plates to change the capacitance or something like that. The sound is somewhere between a suitcase vibrato and a rotating speaker, leaning more to former than the later. They're not terribly loud, but when I put a tube-pre in front of it, it sounds great and gives sufficient volume. Mine has some noise (I think it's from the space generator), but not enough to be distracting unless you were playing a quiet solo gig.
$400-600 is a reasonable price for a functioning set, but don't buy one that's missing the control box.
$400-600 is a reasonable price for a functioning set, but don't buy one that's missing the control box.