You may consider vertically biamping with a pair of quality ss amps. I've been using a pair of Blue Circle BC-28 hybrids to drive Meadowlark Blue Herons (not a particularly difficult load) with noticeably more powerful and articulate bass. I've biwired with other system iterations and never perceived much or any benefit. The BC-28s are single ended, but the BC-22 and BC-26 are ss and balanced topology (FWIW, Mr Yeung has said the BC-26 is far better than the BC-22). There's a biamping primer on the Audio Asylum "Audio FAQs" link, which covers the basics (clearly biased toward horizontal biamping w/electronic crossovers which are NOT used with vertical biamping. The author also states that vertical biamping extracts a greater benefit from amps with a single toroid rather than true dual mono designs, but read for yourself). The Cary Audio website also has an article on vertical biamping emphasizing benefits specific to their amp designs, but another useful primer. I'm not an engineer or an authority by extensive practical experience. Hopefully, others will comment on and make any corrections to what I've written. I do know that, for me, this option has been positive.
