[kmcdonou4eq5]

I am looking to get a new amp, preferably used, and am wondering about the sonic differences between the RM-9 MKII and RM-200. I haven't read much between the two and the few comments I have read said the RM-200 might be a little drier, or less sweet.  I know the RM-200 uses less tubes and could be the reason for those comments.

Has anyone listened to them both and have some thoughts?

[GMuffley]

I have not auditioned an RM-200 in my system, so I cannot comment directly on the relative qualities of each amp.  I have owned an RM-9 MKII (and RM-5 MKIII and RM-4 as well) for approximately 8 years and have been very satisfied.  The RM-200 uses a bi-polar, solid state gain stage for the input as opposed to the fully tube based RM-9 series.  If you use the RM-200 in single-ended mode, the input impedance is 15K ohms (30K ohms in balanced mode), so some older tube preamps, with a high output impedance, may have more difficulty with the RM-200, as opposed to the 100K ohm load presented by the RM-9.  I don't think you can go wrong with either unit.

[Roger A. Modjeski]

The RM-200 does many things an RM-9 can't. It has a wider range of impedance taps (1,2,4,8 ohms), many dB lower hum and noise and can be  driven balanced or unbalanced with identical performance.

We offer a high impedance option (100 k ohm) for those who desire it though most tube preamps drive it just fine as is. Passive preamps have no problem driving it though some potential users think there are loading restrictions on passive preamps which is not the case.

When I designed the RM-200 I considered every aspect that makes a good amplifier and I am very pleased with the results. Now that the world is "going green" I trust those who care to take notice that the RM-10 and RM-200 are the lowest power consuming amps in their class.

[kmcdonou4eq5]

Roger, thanks for the response. Do you notice any sonic differences between the two models, other than the lower noise and hum from the RM-200?

[jamesgarvin]

Roger, what does the higher input impedance do to the noise level of the 200? Thanks.

[Roger A. Modjeski]

The RM-9 and RM-200 are quite different and any comparison is difficult. I feel both meet my standards which are far higher than most tube amplifiers. In the pages of Stereophile you will find many amplifiers which suffer from excessive hum (over 1 mV), poor damping and high distortion.

When I was able to achieve the same neutral sound with 4 output tubes instead of 8, hum levels a good 10 dB lower and lower power consumption I discontinued the RM-9 and replaced it with the RM-200. Both are fine amplifiers. The cost to build the RM-9 had risen to the point where I could no longer offer it at the value that Music Reference is known to be. The RM-200 is has been in the Stereophile Recommended Components since 2001 with $$$ designating a great value.

[K.C.]

A friend of mine has an RM-200 and I have an RM-9. We got together and did some listening to both in the same system, in addition to a couple of other amps we each own. To try and be fair we ran them passive to eliminate any preamp influence on the sound. This of course eliminated balanced as an option on the RM-200.

Yes, there is a slight difference between, but it is slight and they both have the MR sound. Neutral, great soundstage, quiet and NOT tubey sounding. They're both great amps and neither one of use would be any less that happy to have either amp. The lower noise floor of the RM-200 was not readily apparent listening that day. I don't doubt it is there, but neither amp exhibited any noise we paid any attention to.

As I write this I'm listening to my RM-10, it too has the RM MR signature sound. I do use it to be 'Green' when only listening to music casually. Being that it's only a cable-swap away from the RM-9 it's great fun to have the choice. I have the Quicksilvers, Counterpoint and Thresholds near by as well. They rarely get used.