Music Reference RM-200

I've used an Atma-Sphere MP-3 with the RM-200. Both units are fully differential from input to output which is an added benefit. I really don't know of another preamp that is fully balanced like the MP-3 but others might have recommendations there. However, there are plenty that offer balanced outputs which is not quite the same.

As for the tube swap I'm trying to save you that phone call because you'll be speaking to me. RAM 6BQ7A hand tested by Roger. You can play with other 6BQ7A or their "equivalents" at your own risk. Good luck trying to get those output tubes to balance. The driver and output are tied together so the offset of the driver tubes is critical.

The damping of the RM-200 is 10. That puts the output impedance at just under 1 ohm. The nice thing about Roger's amps is they respond well to light loading, which he recommends whenever possible. Meaning if you have an 8 ohm speaker use the 4 ohm tap, a 4 ohm speaker use the 2 ohm tap. Less distortion, more efficient operation, and you get more damping.

There's also an RM9 MK2 listed by TMR with vintage Siemens EL34 tubes for $2,499 (can probably negotiate down to $2,250).  I have the RM9 MK2 and have success with both RAM EL34's and GL KT88's.  Great amp and a great value!   I've owned many tube amps, some that retailed as high as $18K, but the RM9 MK2 is as good as any tube amp I've owned.

That $1500 price for the RM200 caught my eye.   If I were in the market for a tube amp I'd snap it up in a heartbeat!

Me too, @pdreher. I bought my original for $2,000, and sold it for same when I found a Mk.2. Another balanced (via transformers) tube pre-amp that plays well with the amp is the EAR-Yoshino 868L (line only) or 868PL (take a wild guess ;-), or if you’re really flush the 912. I think ARC pre’s should be avoided, as they don’t like the amp’s low input impedance. The EAR’s will drive a 600 ohm load!

Wonder how a Schiit Freya (balanced outputs) would pair with the RM-200?  It seems to work well with several power amps I’ve tried it with so far.

I picked up the RM-200 recently from a local seller for $1500. I'm not sure if the tubes were originally from Roger because none of them have the Ram Labs print on them. They came with Gold Lion KT88's, which I know that your Clio and Roger sell. The drivers are Sylvania 6BQ7A's, which I don't think are matched. 

I also own the RM-10mk2. I'm not sure if I can afford to hang on to both, but it's too hard to decide between the two!!! They are both awesome, different, but also similar in things like rhythm, imaging, quietness, and drive. Where they differ might be to tube pre matching (they are both being driven by a Juicy Music Peach). The RM-10 seemingly more clear/air and has a little more punch. The 200 has better tone and more grounded low end with a deeper soundstage, although it is little more full creating what sounds like some midbass bump ( I could being not describing this correctly). The RM-10 can be a little fatiguing at times, but I think if I drove with a passive (LDR perhaps) it might mellow things out. The 200 is smoother with less fatiguing highs. I think with the 200 there might be a little impence issue with the 15k unbalanced input of the 200 and the Peach output imp. of 3.5k

The Freya seems the most likely choice given the differential balance and the friendly price tag :)