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Now about Vintage Infinity Kappa 9's, Infinity RS4b - Is my receiver capable? -

post #1 of 13
Thread Starter 
EDIT: Read post #5 to see an update - Kappa 9's

I am most likely picking up a pair of vintage Infinity RS4b's tonight for $250. They are in great shape from what I have seen in the photos.

I am wondering if the mediocre Sony 5.1 receiver I have can handle these without damaging the delicate EMIT tweeters or mid-domes?

Receiver is a Sony STR-K502, 100wpc @ 8 ohm. It works fine with my Infinity Entra-ONE bookshelf speakers, but this old school pair is certainly a lot more demanding, requiring more current with lower resistance drivers.

I doubt I will go over 60% volume, if that, depending on how loud they are. Possibly more if they are too quiet. I won't be cranking them at all though.

I intend to get a much better power amp or integrated amp for these when I am able. Any suggestions on something around 100-200wpc @ 4 ohm, 2 ohm stable, at a reasonable price.

Here is a link to some info about the speakers with pictures and a schematic. Click RS4b on the menu at the left.

post #2 of 13
Thread Starter 
post #3 of 13
you probably will get an answer at the audiokarma dot org 's infinity forum...

hope that helps....
post #4 of 13
Thread Starter 
That' the thing, I signed up there, waited for the unusual activation, and then approval after activation... only to come back to a message saying that my account is banned, forever, for no reason given.

I asked why and got no response.

EDIT: It turns out you have to have an isp email address, I looked for that in the rules, but glossed over that info where you enter your email... I will try again.
post #5 of 13
Thread Starter 
I still haven't been approved by a mod for the AK forums.

By some luck I found some Kappa 9's in decent shape for an amazing price... not much more than the RS4B's I was going to get, also a decent sony stereo power amp thrown in, and he delivered. I might get the RS4's as well, but I'm not sure I can afford them after paying a bit more for the 9's.

I think they need some work. Have to check the tweeters and super tweeters to make sure they aren't damaged. Maybe a nice clean and oil, and they need all for 12" woofers re-foamed.

Until I get approved for AK.org I will ask you guys about 'em...
post #6 of 13

I used to have a pair of Kappa 8's and I really believe you are going to need a powerful amp to drive your 9's. I had looked and listened for a long time before choosing those speakers but tried a few amps before a dealer took pity on me and sold a 200 watt MacIntosh at a discount so I could actually drive them. Those things took a lot of AMPS! they sounded great still after I had them for fifteen years.
post #7 of 13
Thread Starter 
It looks like this sony that he was using has somehow managed to not kill any of the tweeters, and I don't hear any scraping on the woofers coils. The amp has a safety circuit built in that shuts down if its asked to do too much... So it's a miracle or something.

I figured since he hasn't killed the amp or the speakers with it so far, its safe to use for now. And they sound amazing, so much sound and louder than I like if I turn it up a tiny bit.

But I know that with a real amp these things will come alive with a lot more sound and clarity.
post #8 of 13
I agree with Sailor Bill.

I used to sell Kappa 8's back in the day, and they do best with a good amount of power. I can't remember the impedance, but I seem to recall they were 6 ohm.

I've run them with a Luxman R117 (160w x2 at 8 ohms), and even that wasn't really ideal.
post #9 of 13
Thread Starter 
They are 4-6 ohm nominal, but dip down below 2 at some frequencies or so I have read.

I got approved for AK forums, and have been getting some help there.

Thanks for the replies.
post #10 of 13
I have a pair of Infinity Kappa 8's and i have the same problem. I have a Parasound HCA 1000 THX amplifier, witch has 2X200w in 4 ohms, but when i increase the volume, my overload lights are starting beacause than is going under 4 ohms.
So...i have the same question...whitch amp goes well whith this loudspeakers?
Could somebody give me the exact link to the Infinity forum beacause i can't find it?
post #11 of 13
Ok, i found it but i can't subscribe...
post #12 of 13
I just ordered a Adcom GFA-555II on ebay. It has a lot of power: 2X200w in 8 ohms, 2X325w in 4 0hms and 2X600W in 2 ohms.
post #13 of 13
I have a pair of Infinity Kappa 8.2i Series II speakers and use two 250 wpc high current Soundcraftsmen amplifiers to drive them, one for each speaker.

One GFA-555 is not enough, better get a second and use one per speaker...
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