For me, they are super effective on my phono cables, between the turntable and the phono preamp. I used to hear radio stations faintly when listening to records. The AQ RF Stoppers cleaned up this noise very well.
Notably, the phono signal is often the lowest voltage in a system, requiring the most amplification boost, and a little bit of RF noise that the cable picks up gets boosted along with the signal. However, by the time you get to speaker cables, RF noise really shouldn't be a factor.
I don't know what's causing your hiss. Sure, go ahead and try the RF Stoppers -- they aren't that expensive, but my guess is you may be hearing something else.
Notably, the phono signal is often the lowest voltage in a system, requiring the most amplification boost, and a little bit of RF noise that the cable picks up gets boosted along with the signal. However, by the time you get to speaker cables, RF noise really shouldn't be a factor.
I don't know what's causing your hiss. Sure, go ahead and try the RF Stoppers -- they aren't that expensive, but my guess is you may be hearing something else.