Infinity Kappa 9


Hi, my name is Laszlo, new in Ps Audio forum

I looking for some recommendations Ps Audio amplifier able to drive infinity kappa 9 in extended mode without shut down amplifier every 2min!

Also interested me vintage stuff from Ps Audio! PS Audio 200C ??

Paul your IRS just simple fantastic!

Congrats on your new speakers!

Thank You



Hi Laszlo,

Does your current amplifier shut down due to overheating or does it shut down to protect your loudspeakers?

Which amp do you use at the moment?


Some vintage Rotel, but shut down because it works only 4-8ohm!

Infinity in extended mode .07 ohm!!! Normal mode 1ohm! Ps Audio 200c able to produce 1.5ohm but that weak!

Any Ps Audio power amp able drive them? Or tube amp??


The old infinity stuff is tough to drive. David hafler made some vintage amps able to drive them fine.

Model DH220.

Or model DH 500.

Also aragons 4004. Is more than able to power them as well.

I have both of them they can be bought cheap on eBay or audio gon

good luck


Thanks for your recommendations,

Hafler and Aragon able to drive them in normal mode of course moderate sound level ,but not in extended mode! In extended mode will shut down ,or kill them!! both amplifier, after few second! Infinity Kappa 9 is not joke, in every aspect!


Then try the Aragon 8008 BB. ITS two mono amps in one box.

I use them to power a pair of RS1B. They have 6 8 inch woofers on each side. Move enough air to move curtains behind me . They do 2 ohm loads too.

Worth a shot.


Yes, I know these speakers RS1b little brother of IRS! But you know huge differences between 2ohm and 0.7ohm!!

On the 2 ohm able to drive lots of amplifier, but on 0.7 ohm almost impossible!!

If I can’t find amplifier from PS Audio, I will grab old but awesome Krell KST 100 able to drive any speakers on the planet, dig down to 0.5 ohm!!!

But Arnie back in the time highly recommended even for this speakers tube amplifiers!

But thanks for your recommendations!



As much as I love arnie I never bought the tube for woofers being good. Mids and tweets yes.

I had some old krells I sold a while back that I was using the IRS V set I have.

But your correct about the imp even the irs dips to below 2 ohms about 1.7 or so.

But not .7 that’s amp killer territory like the appogees did. Wow. Maybe you. Could try and imp transformer to raise the input imp to something normal like 4 or 8. They did make them back in the day for apologies and and some others too.

Good luck and please post back what ever you do.



Hi Al

Infinity IRS just beyond any dream!

Up to $500 Parasound HCA 2200, over $500 Krell! As you know Parasound not even last words in audio history, just able to drive kappa 9 without shut down! Yes, Kappa 9 dip down at 40hz and 9K 0.7 ohm!! in extended mode! I had Apogee’s much easy to drive than kappa 9.

Of course I used with them ARC tube pre-amp, and Krell power amp.

And one more thing!

I m not agree with only for tweets and mids can be use tube amp for kappa speakers

My buddy he use over 20 years kappa 8 with single ARC Classic 60, without any issue!! Only 60 watts per channel! And works! Able to drive whole speakers!