Cables for low power amps and Horns?

Cables always make a difference. I don't think one can predict what specific cable you would prefer in your particular SET/horn system. I have such a setup and I ended up with NBS cables, but, this was hardly after any kind of exhaustive search. At the time, NBS had several distinct series of cables with quite different kinds of sound (one series warmer, the other leaner and more dynamic). I went with the warmer series after auditioning cables from my dealer.

That particular dealer sells only low-powered tube gear, both pushpull and SET. As an Audionote dealer, he sells their cables. I have heard the Audionote cables and like them very much. Another brand that he likes is Snake River (I have not tried this in my system). This same dealer said that he tried the cables with a liquid slurry conductor (T.E.O., I believe) and like the sound of those a lot. He did not pick up the line only because he surveyed his current crop of customers and none were particularly keen on replacing what they have.

I also got to hear in my system the speaker cables from the turntable manufacturer Basis. These are very interesting cables -- the sound when I replaced my NBS cables sounded considerably louder (given the low resistance of either cable, it is hard to account for this subjective difference). The sound was, for my system, a bit too hard edged, so I kept my NBS cables, but, if one is looking to perk up the sound of a sleepy system, the Basis cables are a contender.

I have heard, at shows, SET/horn systems using Crystal Cables and the systems sounded quite good. I don't know what the cables contributed, but, it does appear that exhibitors with such systems are willing to use their product (a form of endorsement). My local tube system dealer has also endorsed these cables (he does not sell them, but likes them anyway).

I have heard a tube driven system (not horn-based) where Purist Audio Design cables replaced something else (sorry, I cannot recall what they replaced), and I was quite impressed with the result -- the sound was full and rich (harmonically saturated), without the downside that usually accompanies such qualities (i.e., the sound did not become overly murky and sluggish).