Amp for Vintage Heresy

Rogue 120 mono tube amps

Run hot but will put will put on a spectacular sound experience.

Read stereophile review that comes up on google

Add a sub (or subs) or try an amp with a very low damping factor.

If the speaker cables are 12’ (or less) try single runs of 22-26 gauge solid core copper wire as speaker cables (doing so should bloom the bass a bit).

On the cheap try basic copper magnet wire and if that works look into Neotech 22-26 gauge solid core copper/Teflon wire (still inexpensive).

Do not use wire larger than 22 gauge as this will defeat the purpose.

I’m suggesting a $10 experiment (with magnet wire) and I have been using 26 gauge solid core copper speaker cables for 20+ years with excellent results.

DeKay

Such wonderful speakers! They are very sensitive, allowing you to discover any bottlenecks in your system. They also sing with low power, but will never have great bass. 

There are so many mods to the speakers, XO, new drivers, sealing the box, rewire, deadening of the horns and woofer basket....

I have vintage Forte, my friend's system is vintage Hersey. My system is vintage with a 200w MOSFET amp (tube like), and his is SET think it's 8w maybe 10w? Anyway, most of my listing, even at 90+ DB is around 1-5w, they fill the room with sound. Don't need a ton of power to make them sing. 

They do like very clean signal path, will let you hear all the good, and also the bad. Bad recordings will really sound bad, but so will the good, they will sound real good. IMHO, they sound better with Tube like amps over new class D, they need a "warm" signal, or they can sound harsh, tinny, shouty. 

We'll leave out the part about Klipsch Heresy's sound quality and lack of bass for now and focus on doing what can be done to work with what you have. Given their 99dB sensitivity, 10-20 watts is plenty, 30-40 is overkill unless you like loud and have a big room. Also, tube amps are a given to try and tame the Heresy's midrange nasal quacking tendencies' especially on vocals. A small tube integrated like a Luxman SQ-N150. Rated at 10W/ch, it also features a more than compete MM/MC section, and the build quality only Luxman can do. If you're thinking you need the extra power, a Primaluna Evo 100 gives you 40 w/ch of EL-34 bliss. It's really quite nice, if lacking the Luxman cachet. Beyond that, you can shop the various flavors of questionable quality, but inexpensive ChiFi tubes. Proceed there at your own risk, knowing support will be ... uh, limited. A word on speaker placement. Because they lack bass, Heresy's need to leverage as much acoustic room loading as possible, so keep them up against the back walls. Pulling them into the room, as you would most speakers, just kills what little low bass they have. Remember, they were designed originally as a center fill (L+R) for Klipschorns. Finally, even though they're not my favorite speaker doesn't mean you can't do right by them and build something fun and enjoyable around them. You may also want to investigate the various crossover mod kits available.