tireguy: the boulder 500ae amp was the precursor of the current line. it has a well-deserved reputation as a built-like-a-tank powerhouse. the folks at boulder amp are very helpful and should be able to address any other questions you may have. give bruce vanallen a call or send him an email. their website is:
http://www.boulderamp.com/
http://www.boulderamp.com/