need a power amp to run a set of infinity kappa 9s

09-04-15: Audiolabyrinth
Get a krell 700 cx and recap it, call it the day! Your done, lol

Now that would up a rocket up them 24 x 20amp BJT per channel, overkill yes.
http://www.hifisentralen.no/forumet/attachments/vennetra-der-hifimerker/232475d1386850163-krell-fpb700cx-front-lch-original-rear-rch-upgraded.jpg

http://www.audiocircle.com/image.php?id=41346

Cheers George

The Acoustat TNT200 has 7amp Mosfet output devices at 6 per channel. A max of 21amp peak, Krells can have 15 - 20amp output devices at up to 4 x the amount, do the math.
The TNT will drive the them ok?, but where the Infinity's load down low and in the upper mids is you need a amp with a Krell like ability to get the best out of them.

Cheers George

Csontos
George, Anyway, it seems that the very nature of mosfets would make them especially suitable for low impedance loads, no?

Simply put NO, they will drive them but will run out of steam (current) at those loads below 2ohm, especially at the below 1ohm points discussed, BJT's (bi-polars) are for these speakers.

And I believe most Infinity's were voiced around Krells, as they were one of the only amps around at that time that could drive these sort of loads "with ease".

Cheers George

Al (Almarg) is right Fartman. You need and amp that will deliver big current, which means one that can almost double it's wattage from 8ohm to 4ohm to 2ohm. This means BJT (bi-polar) output stage solid state type amps, with big power supply, eg: old big Krells.

Because the Kappa 9's go down to .7ohm in the low bass and .8ohm in the upper midrange. And if there are any bad negative phase shifts in these areas those impedance figures will be even lower.

This means Tubes and Mosfets need not apply to drive these successfully.

Cheers George