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Help power pair of Infinity Kappa 9's please

Hi all!
I have a pair of Infinity Kappa 9's:
Nominal Impedance: 4 to 6 ohm
Power Rating: 60-340 watts RMS
Efficiency: 102 dB SPL @1 watt, 1 meter
Crossover Frequencies: 80Hz, 800Hz, 4500Hz
Frequency Response: 29Hz-45kHz +/-3dB
Physical Attributes:
1x - SEMIT Supertweeter
1x - EMIT Tweeter
1x - 3" Edgewound Voice Coil Polydome Midrange Driver
1x - 5" Polypropylene/graphite Diaphram Polygraph
2x - 12" Cast Frame , L/C Tuned Woofers
Dimensions: 59.5"H x 21.5"W" x 8"D

My room is 12'x12', I have $2500 budget and would like to play music off my computer. I need amp(s), a preamp, and a DAC i guess (is the DAC necessary at my low of a budget range?). I know my budget is low so I will be shopping for very used/old equipment. If anyone has any experience, suggestions, or words of wisdom, they would be very much so appreciated.
Thanks,
JT
jtiesel2
tomtab
97 posts
 
I currently have a Stratos DUAL-MONO on my CLSIIa. This amp works VERY WELL with these. The CLSIIa will drop below 1 ohm and this amp NEVER breaks a sweat! Very open sounding and I agree, a little dark.

taken from a post here
jafant
18,804 posts
 
tomtab-

what other gear, including cables, is in your system?
tomtab
97 posts
 
jafant,,, why do you need to know that????    im helping jtiesel2 here trying to find an amp that will work with his kappa 9's.   my equipment is not going to help him
georgehifi's avatar
georgehifi
10,312 posts
 

For these speakers you need amps that give current with (Bi-Polar output stage) that can almost keep double their wattage down to 2ohms.

Look at the impedance graph and you'll see, it a pity there is no phase angle graph done on these as then combined with the impedance dips you may find even more horror scenario's.

http://emotivalounge.proboards.com/post/600160

Cheers George

stefanovitch
64 posts
 
I agree with George and again to tomlab.

The speaker was developed in conjunction with Audio Research M-300 amplfiers.
However Arnie used the SP-11 as a pre and various Threshold models to drive them full range.

For you info the Adcom wont do the job. The Kappas 9 impednace is below 1 ohm in the mid and highs and at the woofer region producing phase angels with minus 70 to 80 degrees. This is near a total short.

Therefore biamplfiying takes aout the stress produced by those angels.

I agree with micthforte that only very high current designs should be used and lower powered amps like the Adcom wont do it. The Parasound works quite well and if you have alow budget you might go for it, but do not expect that it will sound like Audio Nirvana.

For full range I would go with the big Threshold SA series and agood vaccum tube pre or an CJ Premier 5, Audio Research M-300, VTL Deluxe 300 or a McIntosh MC 275.

If your really low on bduget you can go with the Parasound I still would use a tube pre.

Should you ant to biamply you will need a Goldpoint stepped attenuator for matching the gains.

You can use the Prasound for the whole speaker, later use the Parasound for the bottom and apply a tube amp for the mid and highs. You need a seperate passive preamp for matching gains like the Goldpoint stepped attenuator.

Another soloution would be a Mark Levinson No.23 for just 2000$ bucks and use a tube pre like an Audio Research SP-6B or SP-8.


The Martin Logan CLSII does not produce difficuilt phase angels like the Kappa 9's and therefore they are much easier to drive.

I have experienced myself that a lot of money is necessary to keep the speaker work properly and if it is too expensive an Infinity RS2b has much lower requirements.

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