i had a dc offset problem w/one of my recently-purchased old electrocompaniet aw75 dmb amps - it would shut down on loud passages, or transients like a loud pop on a winyl album. the fix was to install caps & resistors internally across the inputs. a quick look-see on my original, purchased-new aw75 indicates that's how it came from the factory, so ec musta realized the problem & made the fix at the factory.
so, don't blame the pre, it may be the amps' fault!

on the other hand, from what some other folk have told me, if ya like the kora (which i understand *is* excellent), ya won't be disappointed w/a melos as substitute...
doug s.