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

I had owned Diapasons for a number of years (and thought it would be my last speaker). It started by driving to the craziness my tube amp (275 wpc Equilibre) and ever since I tried a number of solid state amps. Plinius SA-102 provided marvelous misrange and silky highs but could not drive well low frequencies. I end up my search with amplifier which number of people (I believe incuding Guido) compared with Jeff Rowland 312. It is Spectron Audio Musician III. Now in 3d iteration (Mk2) is very musical in addition to having great bass and iron clad control of the Shahinians. There are a few used here on Audiogon but I saw one new or almost new with Bybees upgrade which convert it into the tube amplifier even SET) but with huge "balls"

The synergy is pure magic.

Good Luck
Simon

Hi Simon and Guido,
thanks for your input.
And how are the comparison between a Spectron and a JR 312 or Continuum 500 (or 501 + PC1). What are the differences, strengths, weeknesses of each?
Thanks
Balazs