Infinity Kappa 8's

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.

Thanks,
Brett

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:
http://www.infinity-classics.de/technik/manuals/Kappa_9_technical_sheet.pdf
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.