The only unknown atm, is if the 'normal' sockets are ok for the subs since I assume they are quite high draw. I assume theyll be fine, but some conflicting info when I googled, but can but try.
The filtered sockets on the ISO-8 will hold the sub back. How much depends on the ISO-8’s internal design, but filtered outlets will impede to some degree.
Low impedance is really important for pretty much everything, even DACs. Transformers usually recharge the caps at the peaks of the AC sine wave. The lower the impedance, the quicker those caps refill, and that tends to translate into better dynamics and overall musicality.
Also if the mains impedance is low, the transformer is drawing current further away from the noisy centre section of the AC waveform where RF crud often is. So even before you add any filters, a low-impedance supply can already help reduce noise.
For reference, I’m using Russ Andrews power blocks with passive filters that knock down noise above about 5 kHz, plus extra filters that deal with RF noise above 1 GHz (so they tame Wi-Fi and mobile interference). I’ve also got passive voltage clamps that kick in around 350 V. The AC has voltage spikes that happen thousands of times a second, but the duration is not long enough to trip a RCD, however they still cause distortion in transformers. The Russ Andrews block itself is double-wired with Kimber TCX, which helps minimise voltage sag. So all eight sockets are low-impedance and suitable for power amps.
And the reason you have a power-block or mains extension as opposed to plugging everything into the wall is there is less ground loops, it's called star-wiring.
Then to compliment the power-block and passive filtering, I'm using low impedance 12TC Kimber Power cables that are braided, when you braid or twist a cable it helps cancel noise. So the power-cable itself is also a filter, and by using a shielded or filtered cable on your components your helping to isolate them from one another, as audio components can put a bit of noise back into the mains block.
Power amps are notorious for causing voltage dips, and those dips can effect more sensitive kit like DACs and phono stages. That’s why high-end power blocks/strips expense goes into the internal wiring to reduce those dips, hence my RA power blocks are double wired with the Kimber TCX. Even with this there is still some dips from the power-amp, nothing is perfect everything is a compromise to some degree.
Worth saying that the house ring main isn’t really the weak point. It’s already at least 2.5 mm and forms a loop, so impedance is decent. The problems tend to start after the wall socket.
The worst thing anyone can do is use those cheap white Homebase/Argos type extension leads. They impede and throw extra noise into the system. People will spent thousands on gear then think a £7.99 extension is acceptable, then spent years changing gear wondering why nothing really sounds correct, but never addressing the AC power.
One advantage your ISO-8 does have is DC blocking, my passive setup can’t remove DC, so that’s definitely a plus I don’t have.
If you’re running an integrated amp, remember that putting the amp on an unfiltered socket means the preamp section inside it is also unfiltered. My integrated benefits from the fact that all my sockets are passively conditioned, so the preamp section is passively conditioned also.
So to summarise, you just have to try the sockets on the ISO-8 and listen to what effect things are having depending on where there plugged into.
The other advantage is more consistence sound quality. If you have ever listened to your audio say at 1am in the morning and thought it sounds better that’s almost certainly reduced AC issues due to lower mains activity. With mains conditioning sound quality is not only improved, but more consistence regardless of time of day.
