Convergent Audio Technology SL-1 preamplifier Jack English 1994
Filet mignon or lobster? That's the level of choice in any comparison of these two superlative tube preamps, the MFA MCR and the CAT SL-1 Signature. Oddly, neither offers balanced operation, as do other excellent tube preamps such as the Melos 333 Plus and Audio Research LS-5. Both use RCA plugs in additional sockets to load their phono sections, while many preamps (eg, the Melos and Klyne) build this flexibility in.
The CAT placed me closer to the orchestra, which was located upon a very wide stage. Within the stage, images were dimensionally full, and the space between performers seemed more real. The midbass was more prominent, the CAT giving an added sense of power to a great deal of the music I listen to. Finally, the Signature resolved more information, especially in the upper-midrange/lower-treble region.
The MCR put me in a more distant seat hearing a slightly narrower stage. Tonally, the MFA had greater deep bass extension and a more accurate midbass level. Its superior dynamics were especially evident during loud, complex crescendos, as was its significantly lower noise floor. The MCR's high gain allowed it to work well with cartridges which didn't come fully alive with the CAT.
Both preamps performed better in terms of spatial localizations, bass articulation, and resolution of low-level detail when their respective soft stock feet were replaced. I had particularly satisfying results with both preamps using the Shun Mook Super Passive Acoustic Resonators. These are large, hockey-puck shaped feet with small support legs/spikes tipped with natural diamonds.
There were no knockouts in this comparison. When price was factored in, the CAT was clearly the victor. If high gain was essential, the MFA took the prize. Aesthetically, the MFA got the nod as well. But when it came to sonics, the units were as different—and as equally mouthwatering—as filet mignon and lobster.—Jack English