Question for First Sound Owners

Just one more idea that hasn't yet been mentioned which is to check the input impedance on the CJ amp . . . The output impedance of the FS is rather high and if my memory is correct it is about 1700 ohms. So using a rule of thumb between preamp output impedance and amp input impedance of 50:1 or even better yet 100:1 then your CJ input impedance would need to be 85K or 170K respectively.

I have used VTL ST-150 with an input impedance of 100K ohms and currently an Art Audio PX25 amp with great results.

usually, if the input impedance of the next stage/piece of gear is 10X the output impedance of the previous stage/piece of gear, it is sufficient. So, if the CJ amp has about 20K Ohms input impedance, it *should* be OK in that it should not load down the preamp o/p stage.
The reason for the lifeless sound for the FS-CJ combination could have been something else besides impedance mismatch.
Eps, your orig post has no text supporting an impedance mis-match - you merely state that it's likely a mismatch issue. How did you conclude it was an impedance mis-match?

Bombay, I never said anything about an impedance mismatch :-)

true! my bad!
(i suppose that I got carried away w/ Kevinzoe's post).

It's kewl :-)