Surprisingly effective
Verified Purchase
This is the third mains filter I have purchased from Brent. When I moved address 18 months ago I found that my system (which I was satisfied with before the move) sounded absolutely awful. I couldn’t understand it but the advice that Brent gave me was the only advice I got that made any sense. I had never realised how much mains interference affected sound quality. We have identified that me neighbours solar panels could be a major issue as the sound quality gets worse on sunny days. Anyway, although the problem has not entirely been solved, we’re well on the way. An unbelievable difference in what I hear today compared with 9 months ago. My Hi Fi upgrade journey with Fidelity Audio will be continuing in 2026!
Martin Tozer | Chorley | November 2025
No noise X HF
“I held off buying this for a long time due to the amount of noise filtering already set up in my system.
I thought I had HF noise filtering covered with three, five point frequency NNHF plug in/diy filters.
Don’t get me wrong, these do make a difference and more so than competitors high frequency filter plugs for a more realistic price.
Do keep in mind that they only operate over the five most common RFI interference frequencies.
After quite a while curiosity got the better of me and I took the plunge for the 32 point frequency NNXHF filter.
I really wish I had done it so much earlier, due to the significant difference it makes!
The filter really gives more emphasis on start/stops in music and brings everything further to life.
Retrieving more detail which is deeper down in the mix. The sound stage also gets more spacious.
Music has further impact.
Don’t be complacent and think you have all noise eliminated, high frequency noise seems to be a separate entity, and needs approaching with specialised filtering, even if you have common and differential mode filtering already.
It is always worth trying something further. This was a particularly successful avenue.”
Chris Dixon | Bristol | February 2025
NNUX HF SE
Hi Brent , after approximately 100 days of the NNUXHFSE being in the system, I think the unit is getting pretty much run in . The original NNUXHF which you upgraded for me has been in the system for over 6 months. I must admit I did cogitate long and hard about whether to invest in this product ( which is your most expensive) as I did already have the NNUHF plug in and my filtration was only 3xNNUSE’s away from your reference system, and I had Russ Andrews Clarity Mains X4 plus Clarity Pro. However, the driving force was I had recently upgraded my system .
On installing it into the system the benefits in noise reduction were immediately obvious. I started by using an old audiophile mains lead , after 2 days I replaced with my third best lead (Nordost Shiva) after another week that was replaced by my second best lead (Nordost Vishnu). After 3 months the benefits were so great I sent it back to you for the SE up grade. Now that is pretty much run- in, I would agree with your comment to me a while ago that the improvements are more akin to a component upgrade that a step improvement. The gains in noise reduction are across the frequency range, smoother highs, better mid range and more low end detail. This has helped me achieve my aim of listening to large scale music near field at the volumes I like. Classical string music is much improved , it was always the thing most difficult to reproduce I have never heard it match live music in any system however expensive. All music sounds better and more detailed and somewhat like my original system 45 years ago, smoother and in particular more involving. This product really highlights how much WIFI has polluted our mains systems in recent times. The product at £1000 is expensive, but I think that in true Fidelity value for money style it gives £2000 worth of benefit.
Brian Daw | London | February 2020
