I had a KX-90 which I stupidly sold about a year ago. The KX amps were kit versions of the Fisher amps. The KX-90 used 7189A tubes in the output section and produced 18-20 watts or so. I recapped mine as it came with the original 50-year-old caps. Whoever built the amp I had did a fantastic job.
Lovely sounding amp. I had owned a few modern tube amps before the Fisher, but I never heard that "tube magic" until I listened to that vintage amp. Here's mine:

