Power amp around $3000 for C-J Classic preamp

03-04-10: Actusreus
I called C-J and the Classic's output impedance is 200 Ohms. If, as general rule, the amp's input impedance should be at least 10 times the output impedance of the preamp...

IMO, that 10x rule of thumb is an oft repeated fallacy. What is more appropriate, is 10x the measured *high* output impedance of the preamp.

Output impedance will always vary along the frequency range. While the CJ may have a nominal output impedance of 200 ohms, it's not unreasonable to expect a high output impedance from a tube preamp of something along the lines of 2000 ohms. For examples, read a few of John Atkinson's test measurements sections of Stereophile tube preamp reviews. You'll see how output impedance varies considerably from the manufacturer's nominal specification.

The bottom line is that the higher the input impedance of an amp, the better will be the success of matching a tube preamp.

BTW, the Vandy 3A Sigs have a fairly flat impedance curve, which would allow the use of tube amplification if that's of interest to you.

In your $3000 price range, look at used Rogue M-150 or M-180 monoblocks: 150wpc (although at 87dB, the 3A Sig might like even more power), 200k ohm input impedance.

How bout the CJ pre amp or used ARC LS5 or even a used Audible Illusions M3A about 800 bucks and an 100K input Imp ARC 100.2 for 1600 this combo put together should smoke all of what you are talking about for less than 1/2 the price
and Made in USA
Best JR

Audioconnection, Great recommendation John.

Have you ever heard the old saying "You can lead a horse to water"?

"10x rule is oft repeated fallacy"

For the stated output impedance at least. Looks like for tube amps you suggest 100x is a better rule.