connected-fidelity CF5A/CF13A Mains Plug Fuse Review

Posted on 21st October, 2021

connected-fidelity CF5A/CF13A Mains Plug Fuse Review

David Price plugs into a box of three audiophile mains fuses…


CF5A/CF13A mains plug fuses

£39.95 for three

Way back in the mists of the nineteen-eighties, as an impoverished student audiophile with too much time on my hands, I set about trying to get my system to sound better on a budget. After doing all the usual tuning tweaks – tightening up my cartridge mounting bolts in my tonearm headshell, tightening up the bolts securing my loudspeaker drive units to their front baffles, and sticking socks in the bass ports of my speakers – I decided to polish every connector to perfection.

I dusted down an old tin of Brasso metal polish and started buffing the mains plug pins on my hi-fi equipment like I was restoring an old classic car chrome bumper. I then polished them with an old rag – likely an item of clothing from my wardrobe at that time – and finished things off with a dash of dilute isopropyl alcohol, otherwise known as ‘tape head cleaning fluid’ back then. I was quite surprised by all the black gunk that came off onto the cloth and even more shocked when I plugged my Linn LP12 turntable back in and had a listen. There was definitely a subtle improvement to the sound, so it was well worth the five minutes of my time and about 5p of materials used.

I duly repeated the trick with the plug’s internal fuse, and sure enough, there was another incremental improvement. It was modest, but there all the same and no amount of cheap student union beer could account for the difference; even when sober, my Sondek sounded better! I duly repeated the trick with all my RCA phono sockets and the plugs of all my other hi-fi components – and never looked back.

These days, I just don’t have time for these sorts of capers. Still, I give my sockets and plugs the occasional squirt of contact cleaner – Caig Deoxit or Kontak are my favourite solutions – and still notice an improvement in sound every time I mete out this treatment on my system.

So, I was interested to see connected-fidelity’s new CF series fuses, as they’re potentially a meaningful upgrade to the sound…


They cost £39.95 for a pack of three, which sounds like an awful lot of money, but the manufacturer has earnestly attempted to produce a serious hi-fi fuse. It’s a good quality item made in the UK and comes in 5A or 13A variants; it’s crucial to fit the correct value depending on your equipment, of course. Each has been deep cryogenically treated, which sees the fuse being frozen for an extended period down to almost absolute zero. This intense cold is said to anneal conductive metal materials and better bond the silver alloy fuse wire to the copper fuse end caps at a molecular level, apparently improving conductivity.

The fuse gets a resonance damping sleeve over the ceramic fuse case for increased mechanical isolation. It then has a blast of ultra-high voltage (400,000V), ultra-low current electricity to burn it in, for want of a better term. Finally, every box of three is supplied with an alcohol-based cleaning wipe to ensure that each fuse’s polished, nickel-plated copper end caps (and the fuse holder it’s going into) is contaminant-free. This design has British Standard approval.


I put a connected-fidelity fuse into the mains plug of a Copland CSA-150 integrated amplifier and sat back, waiting to be amazed. I wasn’t, but I did hear a subtle difference all the same. The music sounded ever so slightly cleaner, giving a sensation of things being a little closer to me as if I was more immersed in the mix. The classic synth-pop of New Musik’s Churches, for example, was slightly fresher and punchier, with a subtly better sense of rhythm and drive. Tonally, things sounded fractionally brighter yet less harsh.

I repeated the trick by adding another connected-fidelity fuse to my Sony CD-P3000ES CD player, and the effect was still very moderate but fractionally easier to discern. Capturing the Flag by The Long Ryders – a great eighties Byrds-influenced indie rock band – was a touch more propulsive, with better detail to the guitar work and a more immediate feel to the vocals. Again this wasn’t night and day stuff, but was audible nevertheless, through my Yamaha NS-1000M loudspeakers.


Given that I’m not a particle physicist, I shan’t be attempting any scientific explanation for what I heard – but I did hear something different, all the same. These connected-fidelity fuses provided a moderate but useful upgrade to my system’s sound and might do the same in yours. Given the modest price, I’d say they are reasonable value considering the improvements they can bring. Some people pay a lot more for less!

Visit connected-fidelity for more information


    David Price's avatar

    David Price

    David started his career in 1993 writing for Hi-Fi World and went on to edit the magazine for nearly a decade. He was then made Editor of Hi-Fi Choice and continued to freelance for it and Hi-Fi News until becoming StereoNET’s Editor-in-Chief.

    Posted in:Hi-Fi Accessories Power Supply/Conditioning
    Tags: air audio  connected-fidelity 


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