In the first two power articles we set the scene for why clean power matters in audio, and then reviewed Audioquest’s Jitterbug FMJ (see here & here). The latter was surprisingly effective in certain circumstances; well worth £40 and a Best Buy award.

The Jitterbug works on the data and power signals in USB outputs. We’re now going to focus on the noise on mains circuits, which derives from two sources. Firstly other devices on the same ring mains circuit and beyond such as fridges and laptops that pollute the signal. Secondly from phones, WiFi and the like generating Radio Frequency interference (RFI) that mains cables pick up. The former is differential noise, the latter common-mode noise. Both vary depending on numerous factors; the age of your wiring, the ‘dirtiness’ of other devices, the strength of your home WiFi etc. Even the time of day can make a difference.

Getting sniffy

Enter mains ‘sniffers’, devices that seek out noise on your home’s electrical wiring. Just plug them into a socket to see how much noise is present. Each works slightly differently. I used a Mains Noise Analyser from Isotek, which gives a colour-coded readout. Green means 0-200 parts of noise per thousand, which is acceptable. Amber is 200-400, getting high. Anything over 400 is red and baaaaad. The analyser also has a speaker on the back;  the louder / more annoying it sounds the worse things are.


Using it around my home gave varied results but I found noise in most areas. Focusing in on the two wall-sockets I use for audio showed that: –

  • Noise levels were fine in the morning (50-100) but got worse around lunchtime (200-250), I’m guessing when neighbours were using more kettles etc (noise doesn’t just come from within your home). The higher numbers acted as the baseline for the results below. 
  • Adding an inexpensive off-the-shelf mains extension block into the mix, plugged into the same wall sockets, made things worse. Noise was now in the 250-300 range, depending which of the ten sockets I plugged the Mains Analyser into.
  • That was with nothing else plugged into the extension block. I figured plugging my laptop power supply into it (without it being connected to the actual laptop) would make things worse as laptop power supplies are notoriously noisy. Nope, the reading reduced significantly from 250-300 down to 50-100. I can only assume the power supply was acting as some sort of noise sink.
  • Sanity was restored when I also plugged the power supply into the laptop though, with noise shooting up to between 500 and 550. Clearly the laptop itself was adding a lot of differential noise. 
  • Finally – spoiler alert for the next article – when I swapped out the bog standard extension block for an audiophile one the situation improved considerably. Both Audioquest’s Niagara 1200 and Isotek’s V5 Polaris registered zero noise on their filtered sockets (two of the Niagara’s aren’t filtered, for reasons we’ll cover in the next article). 

So the results varied depending on the circumstances. A second generic mains sniffer confirmed the gist of them though; my mains carried a fair bit of noise and would benefit from attention. Onto action……

EVO3 IsoPlug

First up was the EVO3 IsoPlug, which works in a similar fashion to the Audioquest Jitterbug, sinking noise that would otherwise be detrimental. The IsoPlug works on the mains though, in parallel with other devices (the Jitterbug works in series, your device plugged directly into it). 

Isotek suggests using several IsoPlugs around the house to address multiple sources of noise. Technically valid maybe but at £115 a pop it would quickly get expensive. I stuck with just the one, plugged into the socket adjacent to the one used for audio. Did it make a difference?

The mains sniffer said a big yes, the noise reading reducing significantly in all scenarios. And sonically the IsoPlug did tidy the sound up slightly. 

Yoshika Colwell’s ‘It’s Getting Late’ is from her first EP There’s A Time. As a debut outing it’s impressive, the maturity in her voice way beyond her years. It’s nicely recorded too, sounding even better with the IsoPlug in situ; acoustic bass was firmer, the sound crisper all round, more detail to be heard. There was also an ease to the sound. Without the IsoPlug a slight edge was introduced. 

Moreover, the benefits made themselves heard within just a few bars. The improvement wasn’t huge. It was noticeable though, and to these ears worthwhile. As confirmed when playing a perennial favourite, Manuel Barrueco’s virtuosic transcription of Keith Jarret’s Koln Concert Pt IIc. With the IsoPlug in place it was easier to follow, the intricacy when he goes ‘off piste’ two minutes into the track just stunning. Without the IsoPlug the notes bled into each. Again, not huge differences but definitely audible.

Onto mains cables. 

Testing of the IsoPlug was with Mo-Fi Sourcepoint 8 speakers, a Musical Fidelity A1 amplifier and a Cambridge Audio Edge NQ streaming DAC. That’s around £10k in total allowing for decent cables (Tellurium Q Black II speaker cables and Audioquest Yukon RCA interconnect). 

Was the use of standard mains cables holding the system back though? Time to find out, enter Isotek Initium and Audioquest NRG-Y3 cables costing £125 & £135 respectively.

The Initium is Isotek’s entry-level mains cable. Made from 99.9999% Oxygen Free Copper (OFC), the cables sit within a PE dielectric (insulator) that is apparently both strong and inert. Cotton fills the gaps between the conductors, the whole wrapped in paper that’s surrounded by a PVC outer. Moulded terminations complete the package, the resultant cable looking rather purposeful. Worry not if the minty green colour isn’t to your taste (me neither), the cable will be hidden away. 

The NRG-Y3 (of which I had two available) is the second in Audioquest’s range of power cables. According to the company, semi-solid concentric conductors control distortion by reducing strand-interaction, with long-grain copper used to minimise distortion from grain boundaries. 0.5% Silver-Plating is applied to the copper base metal to improve Noise-Dissipation, and Zero Tech reduces the electrostatic field between conductors to aid RFI dissipation. All wrapped in a braided black sheath that looks the part. 

Apart from colour the main external difference between the Initium and NRG-Y3 was flexibility. At 14mm diameter (against the Isotek’s 10mm)  the Audioquest cable was stiffer, making it slightly more difficult to accommodate on your equipment rack.


Initial listening was with the  amplifier and streamer plugged into my usual two wall sockets via standard mains cables (so no extension block). Having established a sonic baseline, I changed to two Audioquest NRG-Y3 mains cables. More listening. 

Then came the Isotek’s Initium, firstly powering the amplifier, then the streamer. In both cases one Audioquest cable remained in place. Yet more listening.

The numerous permutations had my head spinning, they all sounded very similar. Indeed on gentler music everything was much of a muchness at first. Switching to ballsier tracks differences began to emerge though.

Take Secret Machines’ How Here Is Nowhere, which opens with a high-energy burst of drums and guitar on ‘First Wave Intact’. The Audioquest cables had a tad more bite, transients were sharper, the kick drums more solid. Overall the sound was more present, slightly more lifelike than with the standard cables. Most notably, dynamics were stronger, the NRG-3Y cables swinging from whisper to roar and back again more quickly. 

The improvements were marginal and didn’t have much musical impact; the Sourcepoint 8 / A1 / Edge NQ system sounded fabulous even with the stock cables in place. But, switching over to dearer cables did make an audible difference, if only a small one.

Swapping out one of the NRG-Y3 cables for the Initium I expected to hear little difference. Instead, I heard a little difference. Powering the amplifier, the Isotek cable was ever so slightly cleaner, low level detail was easier to pick out, guitar transients were even sharper. The music sounded more raw, as intended (I presume). Words that imply the changes were bigger than they were. The Initium just got the nod though.

A snug fit

Beggar me if switching the Initium over to streamer duties didn’t sound even better, albeit by the smallest of margins. Basically the music was slightly cleaner, the reverb on Secret Machine’s opening guitar easier to hear for example. I was expecting the greater current requirements of the amplifier to benefit more than the streamer from a good mains cable. It seems not. 

Audioquest Blizzard

Onto Audioquest’s £650 Blizzard, with a list of attributes as long as your arm. I know not which make most difference. Rather than regurgitating marketing material I’ll point you to the company’s website for the rundown. The patented DBS system that biases the insulator is worth a mention though (it’s the small device at one end of the cable). 

£650 is a lot of money for a mains cable. Not least because it drew sceptical looks from everyone who gazed upon it; I’ve seen thinner anacondas. The Blizzard is also inflexible. And heavy, beware the strain it puts on your amplifier socket. Were it staying I’d put some form of support in place. 

The snake analogy doesn’t extend to oil though. Much as I’m loath to admit it (objectivists I feel your pain) the Secret Machines track stepped up another notch with the Blizzard in place. Indeed the improvement it wrought was more obvious than the other mains cable in this test. The sound had more substance, dynamics were even stronger, detail clearer, the suspense stronger. Overall the music had more menace, the moment when it startles you at the beginning of the track more impactful for example. 

Switching the Blizzard to the Edge NQ streamer retained the improvements but didn’t advance them. So a different outcome than when using the Initium. No matter. 

Overall, the improvements brought by the Blizzard were marginal, far from night and day. It did make a difference though Not a huge one, and being conditioned by the previous two cables I knew what to listen for. But, it did sound better. Which surprised me.

Interim conclusions

It had to be done (did it? says the chap on my shoulder) but boy was comparing mains cables a difficult task. Surfacing the distinctions between them required very analytical listening. The sort that seeks difference for the sake of it, not the sort you hear by music being communicated better. 

Yes there are improvements to be had by spending money on better mains cables. They are not huge, smaller than the impact of better power supplies, better speaker supports and so on. I’d certainly splash out on good speaker cables and interconnects before considering mains cables. But they are there.

The case for Isotek’s EVO3 IsoPlug is stronger, and by dint of it benefiting multiple components it would get my vote versus a single mains cable at a similar price. In absolute terms it’s also relatively affordable, so something the Hifi Starter might consider.

But hold on before reaching for the credit card. The IsoPlug is the first rung on the power-conditioning ladder, with many above it to consider. Might a specialist mains block with built-in filtering be worth considering instead? Something like Isotek’s V5 Polaris with its six sockets. Or Audioquest’s Niagara 1200 with its 7 sockets (two for high current devices). The next and final article in this power series will assess what difference they make. I’ll also have another listen to mains cables; might they make more of a difference when used in conjunction with mains conditioners. The answers should be with you shortly.