Infinity Kappa 8's

What to do? My infinity Kappa 8's keeps eating amps for lunch.The 1st failure was with a Yamaha 200 watt per channel model P2200. Amp went black, I replaced the main fuses on the back of amp, it powered-up with new same rating fuses and then amp died again for good.Tryed another P2200 fuse blew again. I've decided not to try the amp again, for fear of completely damaging my last P2200. This is getting expensive! I'm not cranking the volume at full tilt or pushing the bass tone control past 12 o'clock. The speaker can be Bi-amped, but I've just used a single robust P2200 on them. The speaker wire uses large 1/4 inch bananna connectors, so no bare wires can not touch positive to ground on the back of the amp or speakers and the 4 binding posts on the speakers flat metal plates to connect the two binding posts together for single amp operation. Could a faulty cross-over wreak this havoc upon me. Any helpful suggestions will be greatly appreciated.
Having owned Infinity since the early 70's, and Kappa 9's were here for a while I can tell you what you need to do.
You won't like it but you need to step up to an amp capable of handling a 2 ohm load, one with high current capability. Me, I like levinson, on my current pair of RS1b's, I'm using a vintage ML3 levinson on the woofers, no problem.

I would suggest Classe, older Krell product, Levinson 333 or 336. Do not even think of anything under 200W/channel.

Step up to the plate and give the Kappas what they want. Until you do, you will continue to have problems.


Paul :-)
Those speakers drop down to just under 2 ohms at 90 Hz. The Yamaha might be seeing that as a short. I have tried several amps on Kappa 8's and never had that problem. The Kappa 9's were notorious amp killers in their day as they dropped below 1 ohm. Yamaha did make some very good amps at some times and I had the B-1's, for a while, in a biamp setup with the Kappa 8's. The bulk of Yamaha gear is commercial quality.

If you have a multimeter, you can test for the speaker terminals for a short using the DC ohms. Zero would be bad. Four ohms would be nominal. If that checks out, it will be time to decide if you need a amp that can drive 2 ohms or different speakers.
Speakers are drawing too much current. Krell Ksa200,ksa250,ksa300 ect will drive the #$%^ out of them and not even cough.
I used an Adcom 555 and an Aragon 8008BB to drive the Kappa 8's when I had them.Both amps did the job.

Thanks for all of the helpful comments out there. The Yamaha P2200 has driven Apoggee Caliburs and Mb Quart 980's, both of these speakers dip into the low,low impedance area, and the amp never popped a fuse or shut down. Remember this is not a consumer amp, but an amplifier that has proven it's reliablity over the years in many studios. Upon further investigation I noticed a very well concealed setting for the woofers under a plastic cap located outside the speaker binding & controls plate. The factory setting is extended range. Infinity suggests throwing the switch into the normal position (which it already was in) to reduce the current requirements to the woofers. Next step suggested I'll take, is testing for a short with an ohm meter. These are the other amps I have available to drive the Kappa's. Yamaha M80 & M85 (both 200 watt range)and a friend has a Sumo polaris.Sorry but a Krell, Levinsen and Classe at the power required is just outside of my budget.
Sorry but a Krell, Levinsen and Classe at the power required is just outside of my budget.

There are a few Classe 200/201's listed around the $1200 range. IMHO that's reasonably short $$$ to get the job done right. The Yammie is a good amp, however it just ain't got enough when the impedance dips. That P2200 is about to celebrate it's 30th birthday, maybe it's time to put the old girl out to pasture ;-)

Good luck,

Paul :-)
As someone else pointed out, the 8 kappa can be driven with even an Adcom 545. I own these speakers and have driven them with (without a single "incident") SAE A202, Adcom 545 Mk II, Aragon 4004 Mk II, Hafler 9500, Odyssey Audio Stratos. They are not impossibly difficult to drive. You must either be driving the amplifier hard (into clipping) or there's a short in your crossover.

- Kofi
look for a pair of B&K M200 Sonatas. They're stable to 1 ohm, capable of 150 amps peak-peak, and sound wonderful. They can be found for <$600, and on occasion <$500.
A pair of Carver Silver 9t monoblocs for about $1200 will drive them with complete authority and make them sing. 900 wpc @ 4 ohms. I use them to drive the amp-killing Kappa 9's.
Got a set in my HT system behind a Sunfire. Sound better bi-wired than they did with two Adcom 555's - though neither setup ever gave me any trouble. My bud just bought a pair of 565's for $900 about a month ago. Good luck!
I want to know what power amp, pre amp,and cd player that match with my infinity kappa, thanks ( I have Belles Ones power, and adcom 555, and arcam cd62 ) thanks
So what's a good bi-amp setup under ~$2000 for these speakers? I see the 565's going for $900 as described. Are those good for the low's? What's good for the highs?

The Odyssey Stratos amps are a perfect sonic match for the Kappa speakers and will supply plenty of current. And at a price that won't break the bank. Peace of mind with the 20 year warranty. I use 4 Odyssey Monoblocks for my Kappa 9's and a Odyssey HT-3 for my Kappa center and Kappa 8 rear surrounds. Sounds fantastic.
As a long time Kappa 8 owner I can strongly recommend a simple bypass modification to the crossover that makes the speaker easy to drive and actually better with a more natural and full bass response. Simply unsolder or cut one side of the 12.5 mh coil from the crossover and solder in a shorting bridge across any one of the three 500uf (1500uf total) capacitors that are the first thing after the woofer binding posts. This takes the 'reactor' out of the woofer circuit. Now your amp will just see a common 4 ohm load and the bass will be very natural without the 'thump' where that cap and coil reactor stores a charge and throws it at the woofer while melting your amp in the process. I listened carefully using the famous Hok-Man Yim Poem of Chinese drum CD and it actually hits harder with better decay after the mod and the amp doesn't overheat in the slightest. The Kappa 8's punch that track harder than anything I have owned with just one 12 per side. If you want to keep protection against a DC short from your amp, ignore shorting out the (series) capacitor, but by all means get that evil 12.5 mh (shunt) coil out of the woofer circuit.
Has anybody else performed this mod?

I know this is an old thread but I hope to bump it. Regarding heyjay's modification. I am very interested in doing this. I have been clipping first, my Adcom 555, then a Carver M1.0t, and now I bought a new emotiva xpa-2 rated at 500 watts into 4 ohms. Listening to Jesse cooks Freefall album track #4 (Freefall) has sent even this sturdy amp into protection mode. That track has some very powerful lows (as do tracks 6 and 8)and I am at my budget limit trying to satisfy the needs for these kappa 8's. I am an electronics n00b and would ask if there would be any chance that heyjay could send me a PM with pics and all? Just a thought and thank you
I did the removal of the 12.5mH (but did not bypass the caps) mod last night on my Kappa 8's. My Rotel 1090 can go quite a bit higher now before going into protection and it runs cooler. I did not notice any significant changes in the bass response.

I plan to put in a SPCO switch that will provide normal mode, extended mode and allow the 12.5mH coil to be bypassed. This will let me compare the mod's sonics quickly rather than though the half our change over memory.

The stock Normal/Extended mode switch simply bypasses the 5 ohm, 50W resistor. It does not bypass the 12.5mH inductor which is always in circuit.

The previous owner of my Kappas did some work on the xovers and got ohms law wrong. He replaced the 5 ohm resistors and apparently couldn't find 50Wer's. He correctly put two 25Wer's in parallel to cover the 50 watts but incorrectly used 2.5 ohms think the value summed like the wattage. So the resistive value was 1.25 ohms rather than 5 which meant they were always running closer to extended mode. Explains why I didn't hear a difference and my amps still went into protection mode at the volume setting, regardless of the switch's setting.
Are these mods only for the kappa 8 or is it also beneficial with the kappa 8.1's?

I rand my 8.1's from a adcom gfa-5500.... Never a issue but not enough volume

Married a girl who had 5 parasound hca1500's (4 of which work) and tried a hca1500 in place of the adcom.... Much better everywhere. Then decided to bi amp the speakers and again a nice improvement. Each speaker gets 200-220w x 2..... But I have been debating on upgrading my amplifiers. Thinking of the wyredforsound sx1000 amp..... But I can't decide if it would be a improvement in sound going with a new class d amp..... And also being able to use Xlr inputs on the amp

Doing some house cleaning yesterday realized the foam surround on my kappa videos and kappa 5.1's is failing.... And suggestion on where to get new foam surrounds? Or but replacement speakers?
The Kappa 8.1's do not have the 12.5mH inductor and present a higher impedance load to the amp than the 8's.

I would keep the stock driver and just replace the surround. It's cheaper and you will maintain the designer's voicing and specs. There are bunch of folks that sell kits, with the foam glue and instructions...check eBay or goggle.
Hi All,

What do you all think about using more budget Class H and Class D amps....say Behringer Europower EP4000 and Crown XLS series?  I am using a EP4000 for my Kappa 7's and they sound excellent, maybe a little midrange 'breakup' or distortion at high volume, but really excellent control of the 7's.  The EP4000 however cannot handle my newly purchased Kappa 9's. 

Any suggestions of what amp might be a nice mid/high amp for the Kappa 9's in a bi-amped setup? I am looking for excellent holographic imaging and silky suite highs. ;-)

Also, I am confused as to how to split the signal coming from my pre amp for proper bi-amping.  Do I just buy a split balanced or RCA cable? Or do I use the additional outs on my preamp? My preamp is a Sonic Frontiers Line 2. Please let me know.

The speaker crossovers take care of filtering out the frequencies for the lows, mids and highs, so that is taken care of.
For pre-outs, if your preamp has multiple outputs, run 1 pair to your bass amp and the other pair to your mid/high amp. If it has a single output you can use a quality Y connector or cable to achieve the same result.

There is some interesting information in this discussion, glad I came across it.
I'm a long time Infinity owner since the late 70s, and have had Quantum 5s, Kappa 8s, Kappa 9s, IRS Deltas & IRS Betas as well as an assortment of center channel and bookshelf Infinity models.

I have had good results with Threshold S300, S300MK2, S350e, S500e and Hafler DH200, DH220 (stock and modified) amps, as well as a high powered class D amp from Class D Audio. With the Class D Audio amp, the Kappa 8s would trip the protection mode if pushed to too high a level though, but it does sound nice. Currently testing a pair of Doge Audio Tube mono amps, but have not tried them on 8s yet.

After reading some of the above posts, the 12.5 mH bypass sounds like a good idea, no matter what amp you end up using. A good approach might be to re-purpose the extended/normal switch, leave the circuit in either the default extended mode or optional normal mode, and then use the switch to remove/include the 12.5mH inductor from the circuit. That way you are not altering the cabinet in any way, and can restore the speaker back to factory configuration if desired. I am just in the process of selling a pair of Kappa 8s in Santos, and will recommend that the new owner perform that mod if he is open to it.
Btw, the schematic for the Kappa 9s can be found here:
The Kappa 9s also has the extended/normal mode switch/circuit, but uses a 15mH inductor instead of the 12.5.
I should mention that I have found some small errors on a couple of the Infinity schematics, which are obvious if you have a pair of unmodified speakers to compare with.
The ones I came across were component value errors for C10 and C16 on the Beta schematics, and some polarity errors on the Q5 schematic.