Thanks, Willsw. I missed the statement in the review about the three outputs (RCA, speaker, headphone) being connected in parallel, which of course would not normally be done in a higher powered amp. So, yes, driving a sub and a separate power amp from the RCA jacks via a pair of splitters, or alternatively from a second pair of RCA jacks installed as an option, should work fine.
Regards,
-- Al
Regards,
-- Al

