Agree about an adaptor based system - an SRD-7 Pro or SRD-7 Mk 2 should do the trick nicely paired with a good power amp. Be prepared for a surprisingly excellent sound - lots of power in the bass, nice natural midrange without sibilance. Supposedly the Sigma/404 is less rolled off at both ends than the Sigma Pro (and certainly is better than the original Sigma), but not too many people have dared to try them with an SRD-7 Pro, as that has been against conventional wisdom - direct drive MUST be better. Big power direct drive may be much better, but the entry cost for a Blue Hawaii SE or an SRM-T2 (or the Spritzer/Gilmore replica) is very high.