I wouldn't call 15x30 a small space. But the Fortes won't need much power to fill it up. I'd look at 50 wpc tube amps. I'm sure the Pass and the Luxman are great amps, but tubes are where it's at with Klipsch Heritage speakers.
Oz
Advice for Amp to Drive Klipsch Forte IVs
I just got back into hifi after being away for many many years. My first system, when I was 18-19 was a Kenwood KA-9100 amp, KT-615 tuner, Denon TT, Klipsch Heresy speakers and Teac reel to reel. Loved that setup in a small room. That was 1979-80. I’m now almost 60...LOL...and I’ve got time and money.
Just earlier this year I bought some KLIPSCH Forte IVs, a Denafrips Pontus II DAC, CXN V2 and a small Reisong tube amp while I got on the list for a set of Decware amps. I decided I couldn’t wait and have decided to go SS.
I listen to down tempo, Trip-Hop, Jazz and a little of this and that in a fairly small space. ...maybe 15x30.
I’m considering the Pass Labs INT-25 or maybe a Luxman L-550ax ii.
I do not have the opportunity to demo either of these but have read wonderful reviews and have watched some nice videos about each.
I wanted to get some thoughts on this set up. A brand new Luxman goes for about the same price as a demo INT-25.