Hi Mark if you think the AI L1 is causing high idle noise (which it probably is, being tubed) then simply turn it off. Does the noise diminish? Next, disconnect your interconnects from the power amp & see what changes; my guess is, that won't change the idle noise. If it doesn't then RF stoppers are probably not what you need. If your power amp is also tubed, then any noisy or gassy tubes therein also contribute to high idle noise. Even solid state equipment produces some thermal noise, although full-balanced topologies tend to run significantly quieter.
I will say that RF stoppers that I once placed around signal interconnects acted as filters well down into the audio band, which significantly degraded HF performance. This phenomenon will of course vary according to cable design, but just be aware of it.
I will say that RF stoppers that I once placed around signal interconnects acted as filters well down into the audio band, which significantly degraded HF performance. This phenomenon will of course vary according to cable design, but just be aware of it.