Help power pair of Infinity Kappa 9's please

It depends on what you want and what your financial straight is. Any high quality solid state amp will do the job.

I would recommend that you try new amps, becouse they easily surpass the preformance of the loudspeaker.

I can recommend the Modwright KWA150 one amp or if you have to money you can use a pair to drive the Kappa 9's.

If you biamp I would certainly encourage you to use a vaccum tube amplifier for the midrange and tweeter like the older Sonic Frontiers Power 2 or Power 3. If you use another tube amp, make sure that the output transformer has two ohm or one ohm windings.

To make it sound that good you might spend not less money, becouse the amps I mentioned are not really cheap at Audiogon.

@Rrog:
Most people believe the sound of the amplifier will be degreated becouse of the 0.78ohm load. However, some people met Arnie and he always pointed out to use tube amps, becouse they changed the sound and linearity dramatically due to the impedance cruve.
They will sound better will any high powered solid state or tube amp. It is absolutely incorrect when a power amp can deal with the load that the sound will be degrated. This loudspeaker can react extremely fast and with the right amp I beleieve there is no loudspeaker down to that price range that can play in the league.
I have already heard loudspeakers in the 100 000$ league but it seems that alomost none can come close to the Kappa 9's.
If you have built them up new, remove the polyswitches you will hear what this loudspeaker can really do. I have already heard the Genesis 5 and that loudspeaker is close to that.
I have tube eletronics and solid state eletronics and I have never heard anything that could beat a Kappa 9. They may only be topped by Genesis and the RS-1 or IRS Series.

I have the Kappa 7's and the Kappa 9's. I have the K7's matched with a Levinson No.23 amp, great combo for my room size (17 by 25ish).
The K9's need a much bigger room and 600 watts per chanel or more to truly apreciate them. I would prefer McIntosh MC1201 mono blocks or as others have stated, bi-amp them.............in either case, my opinion of the K9's is that I love the sound that they are capeable of. You just need the room and the budget to let them do what they were designed to do.
If you feel that the K9's are increddible speaks, then you have to commit some fundage to them and you will not be dissapointed.....otherwise sell me your parts because I intend on keeping mine for as long as I can!

From another perspective: I have Kappa 6's, 7's, 8's & 9's all owned since new in 1987. I've powered them all very successfully (right now using the 7's & 8's) with Harmon Kardon Citation 22's. Two amps in the bi-amped mode. I haven't blown anything in 23 years and have driven all of them in various combinations at levels to make your ears bleed listening to RUSH! Citation 22's come up on ebay regularly and sell from $200 to $400.

I think with all the naysayers in this thread, it's worth mentioning that there are two modes for the Kappa 9 woofers to operate in:

1. The "extended" mode, which is the "amp-killing" mode that goes down to 0.8 ohms.

2. The "normal" mode, which puts a 1 ohm, 50 W resistor in series with the woofers - thus raising their impedance to levels more like the Kappa 8.

I used an Adcom GFA-555 to power my Kappa 8s - and I was never for lack of power or stability. The only time I ever blew a fuse was when running a 20 Hz test tone at obscene volumes - and it was the power supply fuse, not one of the output fuses.

You could almost certainly power the Kappa 9s in normal mode with a 555 (or any other similar amp) as well - leaving you a good $2200 or more in the bank to save for an amp that can run them well in extended mode. Until then, you can party hard with only slightly less bass.