Music Reference RM Mono?

I have NOS Telefunken EL-84's and tried them in the RM-10. Roger's stock tubes were just as good sonically, and quieter to boot. I've never heard the Mullards, but for the cost I'll stand pat.

His stock EL84s are Ei? When I bought the amp he was "raving" about the Genalex Reissues, you might want to give them a try in 10,000 hours - $100-120 for a matched Quad from Jim McShane, a bit more from Roger.

Roger commented that he's had to return the last couple of batches of the Genelex reissues. I'm waiting for him to give the okay on the new batch he's testing. Nothing against Jim, but I'd prefer to buy from Roger since it's his amp.

I think that the speaker’s impedance has everything to do with whether 1 or 2 RM10’s are needed. I initially tried 1 RM10 to drive my Totem Mani’s (notoriously difficult load) and then went to a 2nd RM10. The extra 3db headroom was a blessing with my Mani’s, even though I typically listen at low volume levels. When I used the RM10 with my Quad 63’s I noticed no difference between stereo or mono block.

Regarding tubes, I used Amperex for both the EL84’s and 12ax7’s. I found that the Amperex added a little “sweetness” that the EI’s didn’t display.

Agree with Jaffeassc, speaker impedance curve would play a big part as to whether stereo or monoblocks would be needed.