you haven't said what your budget is, but I gather from your post you's shooting for closer to $500 than to $1000. I'm sure others can be more helpful than I but you'll want to specify this.
I'm not familiar with the Kappa9's, although I have a pair of B&M M200 Sonata's which I bought from a guy who was using them to drive Kappa's. I would think the M200's are a good choice for them. Do you know which B&K Model Amps he was using (ie that he burned up)? M200s are very stable to low impedance (ie <2ohms), and they can be found for <$600, and sometimes <$500 for a pair.
Further, I'm not familiar with the Parasound HCA 1200's either, but I have owned HCA1000's, HCA1203, HCA1205, and HCA2200. I prefer the B&K M200 Sonata's to all of them. The HCA2200 is the only one of them that is close to the M200s, but I sold my HCA2200 because I prefer the M200s. I still think the HCA2200 is a great amp and would also be a good choice for the Kappas. You can probably find one for $650 or so.
Kappa 9's need very high current amps. krell Ksa 250 will drive the #$%^ out of them without any strain and do so cleanly with outstanding sonics. Rated at 250 a side into 8 and 2000 into 1 ohm. The krell are cheap right now because they produce a lot of heat from Class A operation. the ksa 250 is smooth not shrill in any way the 9's will like this.
sorry about that. I have $1,600 right now to spare.
The 9's are a notorious load that dip below 1 0hm. Many amps will see that as a short and automatically shut down . For amps, consider Aragon 8008 and Palladium monos or Spectron. There is no such thing as overkill for those speakers but, as your friend will confirm, underkill is easy and more likely to be fatal.
Other than that, the Kappa 8's are an easier load, shorter, lighter, and don't sacrifice much of the bass.
The 9's received a so-so review in '89 by TAS.
The Infinity Kappa 9 speakers will require at least one stereo amp that has a huge amount of current as well as high wattage while also being fully stable down to 2 ohms. The Kappa 9s present a severe phase angle to an amp and many amps that are not up to the task will literally go up in smoke. The more power and current your amp can supply the better the speaker will perform - especially at high volumes producing low frequencies and complex musical signals. Passively bi-amping the speakers (with two stereo amps or four mono amps) is even better but careful amp matching is required. Good luck!
I bought a new pair of Kappa 8's after deciding between them and the 9's and kept them for about 8 yrs. I used Adcom 565 monoblocks and those will work fine with the 9's.
The one area the Kappa's could use a little help is in the mid-range and with that, you might want to look into the VR4 spkr. You get tighter bass, which I'm assuming is one of the reasons you're looking at the 9's plus some very good mids and excellent extension. Look at VR4 models with soft dome tweeter, not metal.
I actually have 2 Adcom 565's running a pair of Wharfedales as we speak (have a 555II in the closet gathering dust). Someone told me that Adcoms are "bright" on Infinity's but after 10 years of Field Artillery in the US Army, I usually have to boost treble a little more than usual anyway. I have local access to 2 Parasound HCA1200's for $800.00 (ex Bjorns audio employee) but have never seen an Aragon or Sunfire besides in a mag or on the web. 8th largest city in the U.S. and there is no such thing. The LOW average income here may have something to do with it.
bdgregory, he sez they "were" ST140's or something like that.
maybe I should add that I am a moderate to low volume listener. Listen to a little of everything but mostly jazz, new age, and lots of technopop i.e. U2, Cure, Radiohead, New Order, etc.
Mt, a few thoughts based on your followup comments,
1 - I can imagine the ST140 wouldn't last long at all with the 9's. It's a nice little amp (I have one), not in the class of power of the others discussed above.
2 - IMO, given your budget I would pass on the HCA1200s, and look for one good used HCA2200, or better yet an HCA2200-II, and even better still, an HCA3500. All of them will sound much, much better than the 1200, and I expect have an easy time with the 9's. Based on your listening preferences you'll like them better.
3 - I still like the B&K M200 Sonata's used - there are some advertised here now, and also on ebay. Probably not a match for the Parasound HCA3500, but better than the other Parasounds to my ear.
Finally, I'm not familiar with the Adcoms or many of the others recommended above - so my comments aren't to indicate they're not better options. I'm only offering my preferences.
Kappa 9s are incredible speakers and a bargain for what one might pay for them today.
The brightness issue that has been attributed to them comes with the fact that most people do not have dedicated lines, running the amps that are plugged into the Kappas.
The worst liability that this speaker has is in its demands of power and current.
I say go for something like the Krell someone had recommended or I have read somewhere of someone running them with the YBA PAssion Monos....400 watts, expensive, but sure can do a job with them.
The issue that I have with some people questioning the Kappa 9 sound is that at today's used prices, most people who purchase them would think of pairing them up with amps that might be used "price-wise" compatible.
I spoke to Ric Shultz at EVS and even his newest amps, which are supposedly stable at "no-load" might have issues with the Kappa 9s.
The nearest relatives to the Kappa 9s are the Genesis speakers that were designed by Andy Nuddel after he left Infinity, with the final masterpieces of Infinity being the original Kappa line. See what the Genesis go for today...and you will see that the Kappas are a bargain with a big(amplifier intolerance) compromise.
I have a set of Kappa 9a's which have resolved the amp eating issue. The a stands for a filter for the very low frequency that sets the stage for the low impedence amp killing problem. I have used the switch when running from my Yamaha unit but omit switch use when driving with Adcom monoblocks. If you are lookin for Kappa 9's you might as well inquire about the 9a's. They were the last year model before being discontinued. A great speaker.
Cool, other brethren who are running 9's ! For what it's worth...and I know that many will strongly be put off by the suggestion...I've been running a totally restored pair of 9's now for some time using a class D integrated amplifier from PS Audio (GCC-250/500). Sure, I'll catch grief from both the tube AND the solid state camp but...I'm sayin that as a (now) almost 46 year old longtime listener that the combination is pretty tough to beat for under 50K. Shocking? OK, well, maybe I'm crazy and I don't claim to have seen or heard it all; but the gain cell system can crank these things so loud that you'll break the neighbor's windows for hours on end without even getting warm. AND, it's INCREDIBLY clear, accurate, and fast without a hint of colour (as far as I'm concerned). Soft passages are spot on...highs with the 9's are unmatched in my experience. Just a thought, glad I've stumbled across the site. Would LOVE to hear other's thoughts/experiences as well. As to the speakers...GET A PAIR if you're able in any way. You WILL NOT be disappointed :-)
The Kappa 9's brightness issue comes when you do not use a tube pre or a solid state at the mids and highs.
You might try an Audio Research SP11 or Threshold FET 10e/11g
then the brightness issue is gone!