ROGUE SP-5 OR MODWRIGHT LS-100

I had a new RP5 for a year and a half.  Out of the box it sounded great with the stock tubes but really came into its own with NOS Mullard tubes.  It was a very quiet preamp with many options.   It was very dynamic sounding as well.  I ran it with an Odyssey Stratos Extreme and later with a Conrad-Johnson MF 2550 amp. 

I was about to respond to the OP but stereo5 took the wind out of my sails. I would not have guessed that the RP-5 would have been a good match for either of the amps mentioned. Insufficient voltage at its rated distortion to drive the MF 2550 and too high an output impedance to match the Odyssey. Just goes to show you personal preference can trump specs. There is no substitute for auditioning with your own equipment if you are trying to match a tube pre-amp to an SS amplifier. 
If I were shopping for a pre-amp for a 4B3, I would be looking for something capable of 2V rms at its rated distortion with an output impedance about 200 ohms or less to create my short list, then keep my money in my pocket till I could audition candidates.

thanks for the great information ... keep the suggestions coming !

@mtmug...……………………...

Before I bought the RP5 preamp, I contacted Rogue and talked to the chief designer.  I read him the specs on the Odyssey amp and was told it would be an excellent match.  So  much for specs.  As a matter of fact, the Odyssey sounded better than the Conrad Johnson amp and I was quite sorry I sold the Odyssey and bought the CJ..  I also used the RP5 with the McIntosh MC152 amp and it sounded better than the CJ.  I went all McIntosh and upgraded the power amp and sold the RP5 for the Mac C2500 tube preamp.

I had a LS-100 for several years.  Excellent preamp with the right tubes.  Have heard the Rogue RP-5 a few times, but never in my system.