JRDG Jeff Rowland amps with Shahinian Diapason?

I have used JRDG models 7M monoblocks for 10 years, mostly on Magnepan 3A speakers. When I changed speakers to Vienna mahlers, the 7M yielded a very sweet sound, but just slightly too rich in the bottom 2 octaves. This was expected, because the 7Ms have a damping factor only around the 200 mark, and the Mahlers are notoriously difficult speakers to drive. After a few months I upgraded amps to the latest JRDG 312, and all controll issues disappeared. . . still have the magical sweet JRDG sound that I love so much, but with a lot more top to bottom extension, greater detail. . . and with very fine, controlled, and pitched bass. The Continuum 500 integrated will yield a similar sound. 201 and 501 will not sound quite as refined initially, because they lack a key component of the other 2 models. . . a circuit called PFC that transforms AC into DC before feeding the power supply. . . an external PFC device called JRDG PC1 can be added externally to 102, 201, 501, Continuum 250, and Capri linestage.

Let me know if you need more info. Guido

Balazs, as you know, I do have the 312 in my system, and absolutely love it. I did enjoy the Spectron Musician 3 when I heard it 2 years ago for 3 hours in a system otherwise consisting of a slightly home-brewed CDp, HCat pre, and SP speakers. Unfortunately, I have never had the opportunity of comparing the JRDG 312 side by side with Spectron Musician 3 in the same system, so I cannot comment on specific differences.
The 501 monos and the 312 yield approximately the same authority; but the 501 monos will require a pair of PC1 devices (one per monoblock) to get closer to the nuance of the 312. . . It is worth pointing out that the 312 is a much more sophisticated design than the 501s, even though it is based around the same ICEpower 1000ASP modules. Therefore, I am not sure if 501+2xPC1 is sonically equivalent to 312. Some unconfirmed 3rd party reports indicated that the 312 still has an edge, but I have not verified the difference myself.
Continuum 500 is equivalent to a pair of 501 monoblocks, a Capri pre, a single internal PFC device equivalent to the power of 2 PC1s, and an extra bank of output capacitors not used in the 312, which are said to yield even greater authority than the 312. The performance of the C500 is said to be very good, but without having heard it side by side with the 312, I could only guess at differences. . . but guesses are not particularly valuable. DCSTEP may have had opportunities of hearing 312 and C500 side by side, and so may be much more qualified than I to comment. Guido