Music Reference RM Mono?

Yes, it's more linear, especially noticeable in the lower frequencies. Not sure if this is due to lower distortion or the fact there is less stress on the tubes and the amp operates more efficiently. In some ways it appears to have more balls which is evident in transient attacks. You would not think this to be the case since it loses about 25% of it's power, and a little more with my speakers since they operate at around 10 ohms on average. Pretty incredible design is all I have to say. A local friend of my has an early RM-9 and the RM-10 is much cleaner at about 25% of the rated power of the RM-9.

Good, so I am not hallucinating:)

Not unless I am too:)

Hi Pabul57. Firstly, Happy New Year and all the best for 2011.

You have a wonderful system there sir.

To be candid here: I doubt the addition of another RM-10 into the system will reap much of a difference [if any] with the Merlins.

Your tube choice will have a much bigger influence in the the RM-10 [or any other el84 based amplifiers for that matter]

While I do think the new Genelex EL84's re-issues are quite a capable example of a decent el84, they do sound very similiar in tone to the older EI's.

Voicing the RM-10 with tubes.
Jaffeassc's choice of old stock Amperex tubes in the RM-10 is spot on IMHO, in both the front end as well as the outputs.

RE: NOS EL84's.

Simply put, the el84/6bq5 is a wonderful sounding tube, regardless of new old stock or current production... it's all about "tone" with this pentode.
I have been collecting el84's [as well as amplifiers employing that tube] for over 30 years.

NOS Mullards el84's are certainly a good example of the breed and are probably the most distinctive of the type. However they are way overated [and overpriced] IMHO. If you want a bloomier midrange then a good choice perhaps.

The telies have a wider bandwith at the frequency extremes,a livelier tube per say but drier sounding in most circuits.

Amperex [Holland Production] are very very good at everything.
The pre 60,s D getter versions in particular....they are perhaps the best of the Amperex family. Fabulous bass power,depth and definition,a vivid midband thats articulate and 3 dimensional. Possesessing a top end that floats above the sound field and seems to go on forever. However, these are quite rare today [read expensive here] . The later O getter examples from the 60's are very close in character, much less expensive and easier to acquire. No current production example will get you here.

THE HOLLY GRAIL of the el84?

My vote would be none other than the common GE 6bq5 [round plate version only] These just tell the truth regardless of the circuit there employed in. They are in a league of there own! Neither the nos Mullards nor the Telies can capture the air,the breath and magical tone of the GE.
The best news is: There are still an abundance of them out there [for the time being] and one shouldn't have any problem sourcing a quad for little money, somewhere around $100.

All the best in your quest.

Ecclectique. love your note, and I think you are right about
looking at tubes rather than going mono. I will have my eyes
out for some NOS to "play" with. I never heard any
type of Amperex tube I did not like. Since posting, I've
been listening to a lot of music through the RM10 (with my
Lightspeed Attenuator)and it clear to me that Anthony
(Clio9) and Roger Modjeski are right, stick with a single
stereo amp in my situation. I am going to give the GE a try
when I can find them from a trusted tubemongerer. Ooops!
found them at Brent Jesse $80 per pair, not bad. Well get
some.

Cheers! Paul.