Review: Music Reference RM-10 Tube amp

Category: Amplifiers

I did a one day smackdown in my home rig: Music Reference RM-10 vs PS Audio Trio A100. All of us are engineers and music lovers, but I'm the only one who's ever owned a tube amp or a serious vinyl rig. We have varied tastes and experiences.

The rig:
Apple TV playing lossless files and a Panasonic DVD player, both feeding optical digital to a Krell Home Theater Standard (ye olde 5.1). Cables are midgrade stuff like Monster, Mogami and Kimber 4TC. Everything is plugged into a Monster HTPS7000 via OEM cables. Speakers are Definitive Technology Mythos 1. My room setup is far from optimal, with a significant brightness in the upper mid and lower treble.

We all agreed that the RM10 was better for music. How big of a difference varied between the four of us, but there was a clear preference for the RM10. For movies, it was more of a toss-up. When pressed for reasons, I heard "warmth" and "easier to listen to" from people who haven't spent endless hours reading that sort of thing in Stereophile. Here are some of the comments:

"One last point I'd make is that both amplifiers that we listened to sounded great. One has more grunt for pushing more juice though bigger speakers, but the levels that we heard today didn't require much at all - and the tubes were the champions due to the more transparent nature of their technology. I simply thought the experience of listening to the Music Reference was more satisfying."

"For movies, I *think* I prefer the PS Audio amp, slightly. If I was going to dedicate an amp to music, either Amp is sufficient for me, I think. However, I say “I think”, because the low end bass is lacking for both scenarios, and with that portion of the frequency filled in, and the speakers freed up to reproduce only mid/highs, I question whether we’d see different results, and if so how much different. I imagine results would be similar, but I wonder if some of the harsher characteristics of the amps/speakers would be reduced."

My direct impression: With the RM10, I found that we listened to the music. With the PS Audio, we flip flopped discs more. There seemed to be more talk about the music and less about the hardware when the RM10 was in the loop.

My analytical review: The RM10's highs were more right. Cymbals sounded more liquid and less electronic, if that makes any sense. The RM10 is definitely fuller in the upper bass, but the PS Audio has clearly more authority in the lower bass. This may have contributed mightily to the warmth emanating from the EL84's.

Both amps were similarly punchy, which is a serious accomplishment for the 27W RM10 (I used the 4 ohm taps). Only when pushed to levels too loud for the room, did the RM10 get harsh. But the Trio sounded harsh a bit sooner, not due to clipping, but due to it's not-as-goodness. I think the RM10's micro and macro dynamics were better, particularly in the higher frequencies.

All this must be tempered by the agreement that the differences were not large. All of us would be happy with either amp. But there is something that is pulling me towards the MR. Which was not the answer I wanted: I can sell the RM10 for more, the Trio allows more speaker flexibility and it integrates more simply into my hybrid theater/audio rig.

Associated gear
Apple TV, Krell HTS 5.1, Defintive Technology Mythos 1, Monster HTPS7000, PS Audio Trio A100.
The Music Reference RM-10 (I have the MkII version) is a masterpiece. I had the same experience as you in that when playing music with it in my system it just draws you in. It's not big, not flashy (in comparison to my VAC amps), but it has balls and is designed exceptionally well. It's also pretty low maintenance and efficient for a tube amp.

I recently revamped my system, replacing the Mythos 1's with Martin Logan Source's and the Krell HTS with a Marantz AV7005 and added a Velodyne Minivee.

All in all, the rig is far, far better with this setup. Every possible way a system could be better, the changes resulted in said improvement.

One thing I've got to say is that I'm amazed at what that RM10 can do. Electrostats can be difficult loads - capacitive and down to 1 Ohm at 20Khz. But the little RM doesn't seem to mind at all. In fact, its dynamics and top to bottom power are amazing.

How can 27wpc make this much sound? especially when watching a bluray movie like the Pacific, with all the gunfire. Theater-level loud (even with the subwoofer off). Astounding.

I haven't compared it to the PS Audio yet, however. When I do, I'll update the post.
The one amp I recommend to most anyone who asks - if 27/35 watts is enough, hard to beat for my tastes - and the added attribute of being built around the idea of using a passive preamp (all the better).