The Ultimate in Smoke and Mirrors? BUT...

@OP What effect/s do you hear and where have you used them? That's a genuine question. I have a number of them that came in some pre owned gear. But I removed them as their adhesive had failed. I discovered they were there when I heard them rattling in the chassis! So I haven't auditioned them yet.

I actually had one of the early Bybee power conditioners back in the 80s. I honestly could not tell any difference. Since I bought it used at a relatively low price I had no trouble selling it at no loss. 

To answer your genuine question (thank you!): I placed a Bybee on top of the three power cords leading to the mono amps and the DAC/preamp/streamer. I placed the second squarely on top of the DAC/preamp/streamer.

The sound is cleaner, more dynamic and the imaging 'sculpted'. By that I mean there is a sense of acoustic space around each instrument. A more convincing musical performance...

These Bybees are newly manufactured so I don't know how they compare to older models.