[DavidS]

I have Audio Note HE speakers.  I run them with a Mactone 300b amp but have long thought I would move to an EL84 amp (like the new Audio Note Oto Signature) as my ideal mate with my high efficiency E speakers.  Hadn't really paid much attention to Roger's amps before reading about the 200 MKII in this month's Stereophile which lead me to this circle.  And I started reading....

Roger makes an EL84 amp that is well regarded and quite affordable.  Does he also do EL34, certainly the KT88's with the RM-200.  And now I read he is working on maybe a lower powered OTL amp.  Anyone have any thoughts on the sound I might experience from the various amps - okay a thinly disguised play at which amp will match well with my efficient speakers.  Small room - probably too small for these relatively big speakers.  And all kinds of music but heading towards more acoustic jazz, blues, folk, small ensemble classical of late - very nice Bill Frisell Lennon tribute playing tonight via MacBook pro.

[tubegroove]

Roger had a very renowned EL34 design, the RM9, which I believe he doesnt make anymore.  I own the EL84 amp and while I havent heard his other creations, expect a clean and crisp, very low distortion, fast and very musical sound.  The EL84 amp size belies its performance.  With a high efficiency speaker and small room, the 35W/ch should be plenty plenty. Btw, there is another thread on this forum on how many watts one really needs, in case you are interested.

[Ralph]

I own an RM-9 (used) and I have never heard as neutral an amp as this one. No doubt the use of EL-34's contributes to this amps clean and yet powerful output. From what I have read on this site, any amp of Roger's would be equally good. I would also suggest th at you look at the post on light loading the RM-10. Roger believes, as do I, that power requirements for good listening are highly exaggerated. I have a pair of Martin-Logan Sequels hybrid electrostatic speakers and they sound great on the 2-ohm tap, which would give an output of about 30-35 wpc, but this is more than sufficient. It seems that using the load tap that corresponds to your speakers' LOWEST impedance delivers the best sound.
Ralph Steinberg

[Ericus Rex]

You can run the RM200 with EL34s but Roger doesn't recommend using that tube in that amp.  I believe that amp was designed around the KT88.

I've never owned the RM10 but I've had a couple of chances to hear one and it's a really great amp.  Sounds like it would be perfect for your application.

[hoppy08520]

Hello, based on what I've read in my research of MR amps, the RM-10 might be perfect for you in that you have highly efficient speakers, a smallish room, your musical tastes, and the fact that you've expressed curiosity of EL84 tubes. Plus it's quite a bit cheaper than its big brothers the RM-9 and RM-200.

You mentioned EL34 tubes. I have Spendor S100 speakers (89.5 db, 8 ohm, 5.7 ohm minimal) and a RM-9 Mk2 with EL34 tubes and love it, but be aware that RM-9's come up very rarely on the used market. Since January 2011 when I started monitoring the used market (audiogon, eBay, Google alerts, etc.), I've maybe seen 3 or 4 come up for sale. In fact, there's a poor guy on Audiogon who has been putting up a WTB ad for almost a year now (poor guy) and I think he posted a recent thread here as well.

Expect to pay $1700 - $2100 or so for a used RM-9, more if Mk.2. And realize that some of these are 20+ years old and might need a once-over by RAM which runs around $600.

You can find used RM-10s more frequently and you can also buy new ones from MR because they're still in production. Note that there's a MK1 and MK2 model. I'd recommend the Mk2 for the parts improvements and because you'll know it's a bit newer. The RM-10 goes for around $700 - $900 (?) used, with the higher end of that range being for a Mk2 and the low end a MK1. One other reason to recommend the RM-10 is that it's known to be dead quiet, which can be important for high efficiency speakers like yours.

(Note: my numbers might be off a bit but probably not by a lot. You can search some of the other recent threads in which people talk about used prices.)

Whatever you wind up with, I hope you enjoy it.

[Æ]

Not that it matters, but some of the Audio Note loudspeakers are not nearly as efficient as they claim them to be. I have an Audio Note dealer near me, he touted how efficient their loudspeakers are. I knew better, but there was no sense arguing with the guy, lest I upset him. Anyway, I later read a review in Stereophile Magazine, looked at the specs. Big discrepancy between manufacturers listed specs and independently measured specs.

[DavidS]

Wow - very cool to get home from work and have all this great information and experience to read.  Much appreciated everyone.

My speakers are pretty efficient - they replace Zu Druids and aren't quite as efficient but close and easily driven by 8 watt 300b amp.  Much easier load than my Ellis 1801's which are a tough 83db load.

Not having heard any of Roger's amps what I am thinking:

RM200 - why would I buy this - more power which I don't really need, clean sound, maybe more tube like than EL84's, successor to RM9 but relatively expensive to my other options unless I am considering Audio Note amps or even Manleys

RM9 - can only get used but uses EL34's.  Not produced anymore and more power.  Legendary amp but older technology (a good thing vs bad?)

RM10 - have read great reviews about EL84 amps including Manleys and think Lebens and Almarro's.  I am interested in sound of this tube.  Power seems like more full range / clean detail than my 300b's - think 300b's are the usual holographic in comparison and also nice detail

and Roger is working on a lowish power OTL amp.  How will these be different than current offerings.  OTL's tend to be more expensive, and lots of tubes - expensive to maintain and fussy to tune.  But have also considered Atma's for my Audio Notes. 

so still thinking about where my amp lust goes next.  By the way have no plans to get rid of my current 300b's which are actually unique push pull configuration.

[Ericus Rex]

Go through the Music Reference circle to find out more about Roger's OTLs.  He addresses all of your concerns in that circle.  Unfortunately, not all that info is in one thread...or even threads with OTL in the title.  It'll take a while to go through all those threads, but the info is in there.

I don't think I'd call the RM-9 "older technology".  It's still more sophisticated than most current tube designs.  I still think the RM-10 is your best bet.  The only reason to get a 9 or 200 is if you'd need that extra power at some point in the future.  But since you're a 300b fan, the RM-200 might not suit your tastes as it's fast and furious...more like a tube amp with solid state speed and drive.  Not a bad thing, per se, but probably not your taste.

[Clio09]

The RM-10 would do fine with AE speakers in my opinion. Light loading them on the 4 ohm tap would lower the output power a bit but provide lower distortion and be easier on the tubes. I use this amp myself on 94 dB speakers and it sounds wonderful. I would also recommend Roger's EM7 12v but I don't think it is available any longer.

[Ericus Rex]

Also keep in mind that many comparably-powered EL84 amps from other manufacturers use double the amount of power tubes than the RM-10.       Rolling and tube replacing would be twice as expensive with them!

[pehare]

I would think the RM10 light-loaded on 4 ohm taps would be a really nice compliment to those speakers although I've never had the opportunity to hear the AN's.  I've immensely enjoyed a new RM-10 MK II i bought from Roger 9 mos. ago.  Great sound, starless & bible black quiet, stone reliable (bias hasn't budged a thousandth of a millivolt in 9 mos) & perfect for running direct to a source or passive pre. 

[DavidS]

Seems like the RM-10's don't come up for sale used very often.

Been reading a bunch this weekend (been raining non stop).  Amazing how many place the RM-10 comes up in revered tones - Salvatore's encyclopedic site but also reading about amps on Jeff Day's site and there it is again.

Debating the need to be patient and wait for a used one to appear vs. commissioning a new one.  Thanks for all the feedback.

David

[Roger A. Modjeski]

Seems like the RM-10's don't come up for sale used very often.

Been reading a bunch this weekend (been raining non stop).  Amazing how many place the RM-10 comes up in revered tones - Salvatore's encyclopedic site but also reading about amps on Jeff Day's site and there it is again.

Debating the need to be patient and wait for a used one to appear vs. commissioning a new one.  Thanks for all the feedback.



David

David,

Can you give us a few links to the RM-10 postings? The RM-10 does seem to be getting more attention lately.

[DavidS]

The Salvatore site is a bit like my cd collection before I got it in alphabetical order and neatly put in a big shelf unit - or a big filing cabinet with lots interesting / lots not and some certainly dated.  Can't find the exact reference to RM-10 again - on this page is reference to Roger's 300b amp.  Need a rainy day or late night surfing binge to go through this stuff.

http://www.high-endaudio.com/RC-Amplifiers.html

and Jeff Day site - thought this was interesting read with the "Ten" getting reference about half way down from Ron who brought the amps in the discussion

http://jeffsplace.me/wordpress/?p=1237

[Roger A. Modjeski]

The Salvatore site is a bit like my cd collection before I got it in alphabetical order and neatly put in a big shelf unit - or a big filing cabinet with lots interesting / lots not and some certainly dated.  Can't find the exact reference to RM-10 again - on this page is reference to Roger's 300b amp.  Need a rainy day or late night surfing binge to go through this stuff.

http://www.high-endaudio.com/RC-Amplifiers.html

and Jeff Day site - thought this was interesting read with the "Ten" getting reference about half way down from Ron who brought the amps in the discussion

http://jeffsplace.me/wordpress/?p=1237

I found a reference to the EM-7 amp in the first posting. I haven't made a 300B amp yet. I don't think the world needs anymore of those. I am more interested in breaking new ground which is currently on furthering the work of Futterman and the SA-4 I did for Counterpoint.

The second link did have a nice reference to the RM10 and others can find it on the page by typing "RM10" in the "find on this page" function of your browser.

[pubul57]

I owned an RM9 MKII and then replaced it with a RM Special Edition which listed for about $10,000 or so - upgraded parts and point to point wiring and a completely redesigned input stage - Roger made maybe 16 or so. Anyway, it replaced my CAT JL2 which I never thought I would replace, till I heard the RM9 SE - must be one of the very best amps ever made and with 162 watts of power to boot!  Any way, given the heat generated by all those tubes, I decided to try the tiny, little RM10 MKII with a measly 35 watts.  Well, after a long period of time listening to both, I eventually sold the RM9 SE. In my system, needing few watts (89db, smooth impedance) the might RM10 was good enough in comparison to the RM9 SE that I knew what was more than enough amp for my needs - it is as great little amp in comparison with some of the best gear I've owned (a long list). What I tell folks these days is if 35 watts is enough, buy the RM10 and stop worrying about it:) There is something special and in my mind better about the EL84 compared to EL34, even though it is my speaker manufacturers favorite tube for his speakers. The EL84 is magical, and nobody has used it better than Roger - in affordable and reliable product.  With other speakers, the RM9 or RM200 might be the necessary choice, but with your speakers I think the RM10 might be just the ticket, please do yourself a favor and don't think of it as a small, relatively cheap amp, it really is capable of providing you with superb performance and spending more money isn't going to make it any better = not when 35 watts is enough.