2. amps-preamps
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which c-j amp

I'm currently using a c-j PF-2L into a c-j MF 80 all plugged into an Adcom ACE 515 power condtioner into Thiel CS 2's all wired with Straightwire LSI Encore. Some say that the MF 80 is one of c-j's better amps as it only has one transistor per side and therfore there is no issue about matching and smearing, but I've recently moved into a bigger room and am considering more power. I am also considering moving on to Thiels with a more demanding impedance load, from 6nominal/5 minimum to 4nominal/4minimum. My hopes are to improve the bass response of my system which can be a bit bloated on occasion, I do realize that the problem might be elsewhere. Has any one compared the older c-j 2300 (240 watts per channel and supposedly better output into lower impedances) which is all MOSFET to the newer 2250 (125 watts per channel) which is MOSFET and BIPOLAR (supposedly better for bass response). They both seem to be going for about the same price ($1000) on the used market. Any other ideas at this price point would be welcome. As always thanks in advance.
unsound
tweak1
3,660 posts
 
I would highly recommend a Plinius 8200P
kehut's avatar
kehut
668 posts
 
Go with tubes...I recently had the CJ PF-2L which I bought new back in 1997 and know its sound well, this is a good solid Jfet design with minimal feedback.open and clean sounding with a slightly laid back presentation and good, but not outstanding depth and staging(those tube virtues again) I've had it paired with several amps mostly Quicksilver M-60 monos driving Thiel 2.3's, Cary 308T upsample CD(more on this somewhere else) VPI Aries/JMW 10.5 and Lyra Helikon from a Monolithic PS-1/HC-1 phono pre amp. wiring is all Alpha core Silver except VPI which uses Kimber Hero.
After swapping the Thiels for Maggie 3.3R's with another Gon member,I felt a more powerful amp was needed, and bought a CJ MF-2300. Not the "A" version.

Well, thinking this would be a great match with FETS all over the place simulating that magic tube sound was about as disapointing as it could be. I was only glad that I kept my Quickie tubes . Now keep in mind the 2300 is a good amp, but knowing the sound of the PF-2L with
other amps, I felt that the bass was to light weight and the sound was missing the palpable magic I had with the M-60;s..perhaps the newer 2250 with fet/bipolar devices would be a better match. 125W/ ch should be fine for you unless you really need current to drive outlandish loads.. the Thiel 2.3's I drove with the Quicksilver amps sounded very good and even pushed the amps never complained. You could get into a pair for under$1000. Good listening

Kehut
unsound OP
7,329 posts
 
Thanks Kehut, I've heard various tube amps on my speakers, and didn't care for it. The tube amps seemed to accentuate the problems that I think are inherent in the speakers, mind you over all I still like the speakers very much. Interestingly enough I've been thinking of maybe using a tube preamp (Audio Research LS7?) I guess my question could be simplified by asking whether the extra power (with advertised ability to handle lower impedance loads)in an all MOSFET amp (2300) would work better than a lower powered (half) MOSFET/BIPOLAR (with bipolar advertised as being better at bass response)(2250)at cleaning up the bass response of my system?
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