For those that are wondering this is straight from the SMc Audion wed site Q&A.
"The R1 circuit board was created by McCormack Audio to allow them to produce amplifiers from the remaining stock of DNA-1 parts, and to facilitate certain repair jobs where the original board had been damaged. This new circuit board is effectively equivalent to the circuitry in the DNA-225. McCormack Audio is now offering the R1 board as an upgrade, including Cardas hardware and Noble emitter resistors. This makes a very nice improvement with a distinct performance advantage over the original amplifier.
Although the R1 upgrade is not connected with my work here at SMc Audio, some have asked how it compares to my upgrades. Direct comparisons are difficult, but I would say that it delivers performance roughly comparable to my Revision B.
I thought it was a good deal and no I didn't buy it.
"The R1 circuit board was created by McCormack Audio to allow them to produce amplifiers from the remaining stock of DNA-1 parts, and to facilitate certain repair jobs where the original board had been damaged. This new circuit board is effectively equivalent to the circuitry in the DNA-225. McCormack Audio is now offering the R1 board as an upgrade, including Cardas hardware and Noble emitter resistors. This makes a very nice improvement with a distinct performance advantage over the original amplifier.
Although the R1 upgrade is not connected with my work here at SMc Audio, some have asked how it compares to my upgrades. Direct comparisons are difficult, but I would say that it delivers performance roughly comparable to my Revision B.
I thought it was a good deal and no I didn't buy it.