Janine Elliot takes a look at the innovative IsoTek Evo Ascension C15 mains cable costing £3000.

I like a challenge; the most jam doughnuts I can swallow in a minute, or the furthest I can swim underwater. Whilst reviewing interconnects can be fairly easy, mains cables are much more of a challenge. It’s not so easy to do A-B comparisons, and it’s not going to be possible to change all the mains leads of your equipment in a review. IsoTek doesn’t make any interconnects, but they do know a thing or three on mains conditioners and mains cables. I saw their EVO 3 Ascension at The Festival of Sound show in Hammersmith, a very serious looking cable with such a large girth it would do well as cable on a suspension bridge. Coming in a cool purple colour and 20mm physique it is available in choice of connecting options, including IEC C15 or 19, Schuko, Australia, UK or USA plugs. This is no ordinary mains cable, and significantly more complicated than the ones I helped design for Tacima, even if I was proud of them.  This cable is at the top of the range coming in at £3000 making it pricier than many conditioners or balanced mains units.

I must own a dozen makes of audiophile mains leads and 5 different mains conditioners, so I am rather OCD on RFI’s and EMI’s. I wanted to see if this heavyweight product was worth the price. I tested it connected to the input of my top conditioner as well as directly to equipment, such as CD player and phono stage. Looking at the build quality and components alone make this money well spent, and anyone with serious kit in their home should consider quality cabling. Unfortunately, many audiophiles refrain from spending their hard-earned cash on serious cabling, despite the fact that it makes such a difference to the overall sound. Bear in mind that much of the stuff inside all their Hifi is actually wiring, anyway. It is good to see some companies taking mains leads seriously, with GamuT for example now supplying all their products with IsoTek mains leads rather than off-the-shelf kettle leads. They realise that cabling affects the overall sound even with onboard complex mains supply and smoothing capacitors.


The wiring in this unique design consists of 4.0sqmm silver plated continuous cast copper conductors made by OHNO, deep cryogenically treated by being cooled down to -196°C (the temperature of liquid nitrogen). These cables also offer a greater level of purity than conventional OFC cable. The geometry and metallurgy used in this cable are designed to offer superb performance with impressive electrical conductivity. The cable is surrounded by a coiled dielectric of FEP (fluorinated ethylene propylene, better known as Teflon) tubing in order to give an air-space and the closest thing to the perfect dielectric; a vacuum. The virtual air dielectric (or VAD barrier, as they call it) offers a constant (k) of just 1.05, and FEP is also actually a good dielectric itself with a coefficient of 2.1. Each of the individual conductor assemblies is wrapped in Mylar to offer further shielding as well as being a further barrier against RFI. These three assemblies are combined with even more shielding supplied by three FEP tubes of air, helping to maintain that low dielectric constancy plus aiding cable construction stability. The outer jacket is made of purple PVC in order to give flexibility, mechanical damping, and strength. For £3000 I would have preferred a woven outer jacket added just to make it look a bit more expensive. Termination at one end is supplied using IsoTek’s bespoke ultra-high-grade audiophile connectors of solid OFC with pure silver-plated conductors to offer the highest level of conductivity and quality performance. The other end was supplied with a Furutech 3-pin mains plug. I love these as they are easy to grab hold of to unplug from the wall, unlike conventional MK-type plugs.

No surprise, it takes between 8-12 weeks to make each cable, including procurement, fabrication time and testing.  Termination of the cable is also a lengthy process, including hours spent carefully isolating each conductor shield to earth, and then termination and final testing. The plugs used in these cables are made to exceptionally high standards and are large, not least because the cabling is so thick it needed to be big enough to allow conductors and sheath to fit inside. However, being so large might cause problems connecting to your Hifi if the platform or stand is close to a wall. Similarly, both cable and pluggery are very heavy, so if your CD player or DAC box is mostly full of air it might tip it up!


My first listening was using the cable with my self-designed mains conditioning unit. I know just how that sounds with all my sources connected, so made for a good starting point. We might be turning against CD as a source, but the Krell KPS20i is an exceptional player, largely due to the Philips CDM 9 Pro transport and some very clever thinking electronics. Vincent Belanger’s newly released ‘Pure Cello’ from Audio Note Music is available on vinyl and CD. It is excellently recorded at the Chapel at Pomfret School in Pomfret CT, using a pair of Lauton Audio Horizon microphones at close-proximity in XY configuration plus two DPA omnidirectional microphones further back for natural sounding room acoustics. The close mic’ing not only allows a detailed retrieval of the playing but also of Vincent’s concentration with spurious noises emanating from him throughout the performance. What the Evo 3 did more than anything was retrieve even more information such as noises from the bow hitting the strings and a clearer sense of the harmonics. Moreover, the noise floor was even lower. This world premiere performance of Grutzmacher’s ‘Elite Etuden’, which he wrote as concert encores, was even more enjoyable than I expected on CD. This series of 12 pieces use every part of the cello’s range from lowest C to the very highest notes, and due to its complexity most cellists wouldn’t even attempt them. This recording contains four of the best.  I also noticed a greater depth of soundstage and dynamic range in the music, allowing the music to come through with better detail and timing. When the mains unit was used directly to the CD player, that performance was even better. Precision from the violin solo in Vivaldi’s violin concerto in B minor (RV.386) from Mike Valentine’s “Vivaldi in Venice” made the music come to life and added depth to the bass provided by the hall’s reverb in this excellent recording, plus increased space between instruments and lowered noise-floor gave me faith in digits from this fervent analogue diehard.  

Turning right on cue to vinyl I wanted to test further the increased noise floor in operation with a low-level source that can be prone to hum or interference, and no surprise the EVO 3 Ascension added to that noise floor with a clearer depth to the soundstage and more detail to the sound. Playing STS’s excellent live recording ‘Harbour Jazzband’ recorded on their prize Philips reel-to-reel recorder on 1st October 2017 the sound was precise, and I felt I was there in the audience, though as a trad pianist I wished I had actually been playing keyboard. There was a definite improvement in dynamic range as well as no interference from all the other wires that are my spaghetti junction behind the audio separates. Just wish the EVO was easier to manoeuvre behind the equipment; such a complex design means it doesn’t “bend” as easily as lesser cables. “Potato Head Blues” (Louis Armstrong) had some excellent banjo, clarinet, trombone, piano, and bass solo work which was allowed to breathe in this performance, and trumpet fortes were given their full range with no compression or fatigue. Each instrument had its own space and time.  Vocals from Greetje Kauffeld on STS’s album titled ‘On My Way to the 30th Analog Forum Anniversary’ were smooth as silk and the soundstage so open and clear that I couldn’t believe that a length of mains cable could actually make such a difference, but I was converted after only a few minutes. With so much wiring behind all my Hifi – and yes, I know I should keep it nice and tidy – it isn’t always possible to prevent wires from coming into close proximity with any other, but this purple cable made this less of a worry for me. It picked up nothing from any other cable around it.

Turning from my main system to my digital source and Slee Majestic DAC/Pre-amp I decided to play my 24/192 rendition of Eagles ‘Hotel California’. This album can sound rather prominent in the mid-frequencies, but the Ascension was able to ‘eek’ out extra depth from the bass and an overall increase in information from vocals and percussion. Turning to Dire Straits ‘Brothers in Arms’ opening track “So far away from Me” the percussion had more speed and vocals were even tighter. Changing the scene to Sibelius’s picturesque Second Symphony opening Allegretto (Berliner Philharmoniker, Sir Simon Rattle) the soundstage ‘opened up’ even further for me to get inside even more detail from the music, with increased resolution, a bit like watching HD tTV and then moving up to 4K. The Ascension doesn’t “add” anything to the music, rather it just retrieves more of it. I’m glad IsoTek don’t make interconnects or loudspeaker cables. Their forte is power, and this Ascension is a powerful product worthy of adding to your hIfi if you can afford it. Just remember that you might need to pull out your KIT from near to the wall in order to connect it all up.


I was sceptical that a mains cable could need to be £3000, and then I tried it. The extra depth to soundstage, increased speed of presentation and reduced noise floor quickly converted me to its magical powers. Ascension is definitely the right name for this product as it allows all areas of music playback to ascend to levels not experienced before and transcends all other mains cables I have yet tried. Now, whether you have £3000 to spend is another matter, but if you’re serious about your music then you might consider it well worth trying it out.


Build Quality: Excellent build, especially internally, and with excellent quality connectors.

Sound Quality:  Divulges more from the music including greater soundstage and noise floor.

Value For Money: £3000 is lots of money, but could be a cheap upgrade for your serious hi-fi.


Improved noise floor

Improved soundstage
Improved screening from unwanted interference


Not cheap
Need to move your hi-fi out from the wall
Very heavy cable

Janine Elliot

Review Equipment: Pre Audio t/t, AT33sa cartridge, Manley Steelhead Phono-stage, Krell KPS20i CDP, Graham Slee Majestic DAC/Pre-amp Krell KAV250a and Leak Stereo20 amplification, Graham Audio LS5/9 speakers with Townshend Supertweeters, Ecosse, Townshend and Nordost cables, Townshend rack

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