What's the best EL84 amp?

pdreher, you may want to try a SET amp with those Altecs. You'd be surprised at how much you can get from 9W with very good iron. So far, my new RM-10 is actually a bit bass shy compared to the 300B SET amp I have. I've ordered other EL84 tubes to see if that's why but it's noticeable vs the SET and an old Scott EL84 amp I have. Both are tube rectified with huge transformers. I wonder if that's the difference?

@dhcod I occasionally swap in an Elekit 8600R 300B SET amp.  While it does sound nice with the Altec's, the bass is not as well defined compared to the RM9 MK2.  I have Werner Jagusch (MassMutter) crossovers on order... so I'm waiting for those to come in before I decide to try another amp.  I'll likely keep the RM9 MK2, but maybe fiddle with finding a backup.

...with huge transformers. I wonder if that's the difference?

@dhcod Yes, sort of. After dealing with the large potted transformers on the RM-9 which accounted for quite a bit of it's weight, Roger wanted a tube amplifier with a small footprint that he could easily carry around. So for the RM-10 he made much smaller transformers and compensated for them with networks in the circuit. The amplifier is extremely flat from 30 Hz to 20k Hz, but things start easing up below 30 Hz, so that might be what you are hearing.

At the time of it's design 35 watts from a pair of EL-84s per channel was double what other designers at that time were getting out of two pairs of the tube. Putting 700 volts on the plates was unheard of, until Roger did it. This is why the amp punches well above it's weight and has a pretty nice set of balls.

It has lovely balls. It's winning me over.

1+ Manley Mahi Mahi.  Terrifically musical, easy to bias and run great current.  Took them to a shop once to demo their Martin Logans ESLs and they ran the crap out of them.  Salesman was shocked.  They are fun.