@ Ralph It was Wyshak asking the question about the S30. To answer your question from my perspective, Wyshak, the S30 could easily power the Duos no problem. I would still opt for the M60s regardless, tho, because I prefer their lower output impedance. Everything's just a wee bit tighter and more controlled this way. FWIW, I did experiment with pulling half the power tubes from the M60s and feeding the Duos that way but ended up ditching that configuration and going back to the full complement. The improvement was marginal but worthwhile in my estimation.