Shipped from Singapore; delivery options and costs shown at checkout Free FedEx Priority over USD 250 Handmade in Singapore since 2008

Epsilon 5 Pro 6N UP-OCC Copper Headphone & IEM Cable

Epsilon 5 Pro is a 6N UP-OCC copper upgrade cable for headphones and IEMs, laid up as a Type 2 Litz: 126 individually enamelled strands per conductor, 504 per cable. To our ears it sets dense, organic mids and weighty bass against a deep, black background.

  • 6N UP-OCC copper
  • Type 2 Litz
  • 504 enamelled strands
  • 23 AWG
Bass9.1Mids9.3Treble8.9Stage8.9Detail8.9
Configure your cable

Choose your earphone connector and options below.

Loading cable options…

Pure signal. Zero boundaries.

Epsilon 5 Pro

Pure signal. Zero boundaries.

Copper of 99.9999% purity, continuously cast so that its crystals run on almost without a break, then laid up strand by strand into a two-stage Litz of 126 enamelled strands per conductor.

Mò Chéng · Deep Ink & Pure Clarity

  • 504 Enamelled strands per cable
  • 126 Strands per conductor
  • 0.247 mm² Copper per conductor
  • 24 g Weight

Conductor

Eighteen by seven.

In most stranded cable the filaments are bare, each pressed against its neighbours for the whole length of the run. Epsilon 5 Pro is laid up differently. Its strands, each 0.05 mm across and each in its own coat of enamel, are gathered in two stages into a Type 2 Litz conductor: pliant in the hand, and ordered from the core outward.

Epsilon 5 Pro in 3D: the black jacket cut back from 6N UP-OCC copper, cut square to show 126 strands of 0.05 mm, 18 to a bundle, seven bundles to the conductor
  1. 18

    18 strands

    Eighteen enamelled strands of 0.05 mm twist into a fine bundle.

  2. 18 × 7

    126 strands

    Seven bundles, one at the centre and six around it, are rope-laid into a conductor.

  3. 126 × 4

    504 strands

    Four conductors are braided into the finished cable.

  • 6N UP-OCC copper

    The copper is 6N, 99.9999% pure, cast by the Ohno process in a heated mould that grows its crystals to a hundred metres and more. Across the length of a cable, that leaves a conductor virtually free of the grain boundaries found in conventional oxygen-free copper. Purity is only the starting point; geometry, enamel and termination do the rest.

  • Two stages, one pitch

    Type 2 Litz is a rope lay in two stages. Its twist pitch is set so that every strand moves evenly between the core and the perimeter along the run, rather than keeping to one place in the conductor. Each strand takes the same path as its neighbours, and stray inductance stays low.

  • Enamel on every strand

    Each 0.05 mm strand wears its own thin film of enamel, which keeps it electrically apart from its neighbours: 126 strands, 126 separate coats in every conductor. Litz wire was devised to govern how current spreads through a conductor at high frequency. Those gains lie mostly above the audible range, and we claim no more for them than that.

  • 23 AWG

    Together the strands make 23 AWG of copper per conductor, 0.247 mm² in all, for low DC resistance and generous current delivery. Fine stranding means the extra copper costs little in pliability, and the cable stays quiet on the move.

Lattice and Gunmetal

Hardware

Lattice and Gunmetal

The Y-split wears the NA mark and the Epsilon name on a lattice faceplate, set into gunmetal. A two-tone barrel finishes the plug, and the pins are precision-made and plated in 24k gold.

Kind to Both Skins

Chin Slider

Kind to Both Skins

The chin slider is flexible silicone, chosen for what it touches. It sits gently against your skin, it is just as gentle on the cable’s own, and it grips well enough to stay wherever you set it.

Stage and Street

Stage and Street

A light 24 g build in an ultra-soft, flexible jacket, as much at home on stage as on the daily commute.

Epsilon 5 Pro is a 6N UP-OCC copper upgrade cable for headphones and IEMs, laid up as a Type 2 Litz: 126 individually enamelled strands per conductor, 504 per cable. To our ears it sets dense, organic mids and weighty bass against a deep, black background.

Sound Guide

To our ears Epsilon 5 Pro is warm and full. The bass arrives with authority and tactile texture, then decays naturally. Voices are rich, organic and dense, instruments keep their body, and the treble extends smooth and liquid, without grain or sibilance. Behind it all sits a deep, black background, with pinpoint separation and real spatial depth.

Ratings are Null Audio’s listening notes, out of 10.

  1. Treble 8.9 out of 10
  2. Mid 9.3 out of 10
  3. Bass 9.1 out of 10
  4. Bass Depth 8.9 out of 10
  5. Imaging 8.9 out of 10
  6. Headroom 9.1 out of 10
  7. Detail Retrieval 8.9 out of 10
Ready for daily carry

In the box

Ready for daily carry

  • Epsilon 5 Pro cable Your length and connector
  • Premium leather pouch For daily carry

Craft and care

Introducing FlexiPlug

Introducing FlexiPlug

The FlexiPlug is a multi-connection system, enabling users to switch to adequate connectors for their IEMs.

Currently supporting 2PIN, IE300, A2DC, IPX, Pentaconn Ear and QDC 2PIN.

Build Note

Build Note

Designed, handcrafted and shipped from Singapore.

Built-to-order. Lead time around 1 week.

Ear guide (~10cm) is installed by default for commonly used IEM connectors (e.g. 2PIN, MMCX, IPX). Let us know if your IEM/headphone is modified or needs extra customization.

Anti-Yellowing

Made to Last

Epsilon 5 Pro’s black insulating sleeve is made for prolonged durability and resists yellowing, so the cable keeps its look on stage and in daily use.

Caring for Your Cable

Care

Caring for Your Cable

Coil it loosely in large loops and keep it in the included leather pouch when you’re on the move.

Unplug by holding the connector, not the cable, and avoid sharp bends right at the plugs.

Wipe it with a soft, dry cloth, and keep it away from solvents and alcohol-based cleaners.

Every cable has a 1-year warranty. If anything goes wrong, contact us and we’ll take care of it.

Specifications

Technical details

Cable
Conductor Material
6N UP-OCC monocrystalline copper (99.9999%)
Wire gauge
23 AWG, 0.247 mm² per conductor
Geometry
Type 2 Litz, dual-stage concentric rope lay
Strand configuration
0.05 mm × 18 strands × 7 groups: 126 strands per conductor, 504 per cable
Length
1.2 m standard; any length from 50 cm to 3 m in 2 cm steps in the configurator
Weight
~24g
Connector Color
Gunmetal (NL5 hardware)
Solder
Audiophile-grade silver-bearing lead-free solder
Pin contact
High precision fabrication, 24k gold plated
Insulation
Individually enamelled strands; ultra-soft, flexible black polymer jacket, yellowing-resistant
Compatibility
Earphone and headphone connectors
FlexiPlug (switchable 2-pin, IE300, A2DC, IPX, Pentaconn Ear, QDC 2-pin), 2-pin 0.78 mm, Flat 2-pin 0.78 mm, MMCX, A2DC, IPX, A2DC (headphones), Etymotic ER4P / ER4B / ER4S, Etymotic ER4SR / ER4XR, FitEar, JH Audio (with bass control), Sony IER-Z1R, Sony MDR-EX1000, Sony XBA-A / XBA-Z series, Ultimate Ears TripleFi 10, UE / UM / QDC legacy 2-pin, KZ C-pin 0.75 mm 2-pin, KZ / 64 Audio 0.75 mm flat 2-pin, Beyerdynamic T1 / T5p, Focal Utopia, Sennheiser IE 40 PRO, Sennheiser IE 8 / IE 80, Sennheiser IE 300 / IE 600 / IE 900, Sennheiser IE 500 PRO, Sennheiser HD 59X, Sennheiser HD 600 / HD 650, Sennheiser HD 700, Sennheiser HD 800, Mini XLR 3-pin, Mini XLR 4-pin, Shure SRH1540 / SRH1840
Player plugs
2.5 mm balanced, 3.5 mm, 3.5 mm right-angle, 3.5 mm balanced, 4.4 mm balanced, 3-pin XLR (pair), 4-pin XLR, Lightning DAC, USB-C DAC (Realtek ALC5686), USB-C DAC (ESS ES9280C)
Service
Warranty
1 year
Returns
Any build from the options on this page, 1.2 m or longer: 14 days from delivery, unused and in original packaging; 30% restocking fee on returns, none on exchanges; shipping not refunded. Inline-mic builds and cables under 1.2 m are not returnable. Defects are covered by the warranty.
Made in
Singapore, built to order

Find the right connector for your earphones

Customer reviews

Rated 4.9 out of 5 from 41 reviews.

    • 5 stars: 38 (93%)
    • 4 stars: 2 (5%)
    • 3 stars: 0 (0%)
    • 2 stars: 0 (0%)
    • 1 star: 1 (2%)
    A
    Anonymous (Singapore, SG)
    Must try, value for $

    My first impression of the Epsilon Mk II was simply how clean it sounds! It manages to deliver heavy note weight without sacrificing a single bit of speed or micro-detail. It offers a much more agile, high-resolution copper performance—giving heavy riffs all the visceral body they need while easily keeping pace with fast, complex metal tracks.
    ​To my surprise, it actually sounds much better for metal than my regularly used Effect Audio Ares S copper cable, which can feel a bit too slow and heavy on rapid double-kicks or dense walls of sound. The Epsilon Mk II keeps every instrument separated, punchy, and crystal clear."

    My 2cent impression is based on:

    Dac: AK sr25mk2 (Neutral-warm,energetic,intimate)

    Iem: um mest jetblack (quadbrid)

    Cable: Null Audio Epsilon mk ii

    Termination: 2.5 balance

    Eartip: Electech baroque stage

    Genre: metal(metalcore, tech death,post hardcore)

    Support local \W/

    R
    Ronie S. (Sunshine Coast, AU)
    Very Satisfied

    I bought it for my Symphonium Titan to replace the stock IEM cable and the results are really good. I have placed my second order for my Dunu Da Vinci.

    S
    Stanley T.Q. (Victoria, CA)
    Null Audio Epsilon

    Got this cable for my 64Audio U4s, as flat 2-pin cables are not very common (most companies only ship cables with standard recessed 2-pin connectors, which look funky when paired with 64Audio's protruding socket assembly). The cable itself is relatively well-built, although the injection-molded plastic around the y-split does have some bit of fraying, and the plug does have a small, shallow dent. The wires itself are pliable, soft, and don't tangle. The ear hook itself is quite thick, but still comfortable. The fit and feel of this cable is significantly better than 64Audio's stock cables, which actually cost more (retail).

    Sound wise, the U4s is definitely better than 64Audio's stock "Premium" cable (SPC material). It has a slightly poofier bass response, with more meat, but less control. The mids are relatively the same. And the treble is slightly more laid back, in that it kills some of the brightness/harshness the U4s, and many other tia-equipped 64Audio UIEMs I've heard. In general, it makes the U4s more palatable for my tastes.

    The most surprising thing is that this sub-200 USD cable ships with a personalized card that has the owner's name hand-signed upon and a grey leather case, something lots of other boutique cable companies fail to do, especially with their entry-level products.

    c
    chen J. (Toronto, CA)
    You won't regret it

    The cable connection is significantly better than factory original, and it rests comfortably around ears. Most importantly, my IE600 now sounds amazing.

    J
    Ji H.Y. (Gwangjin-gu, KR)
    Highly recommended

    Both the build quality and sound quality of the product are excellent. It upgrades the ie900 without compromising its character. It is lightweight and suitable for outdoor use. Highly recommended.

    A
    A**x (Singapore, SG)
    Good Upgrade Cable for IE600

    I purchased this cable to replace stock IE600 cable. It is a cable with better built quality compared to the stock one. Sound clarity improve by a bit.

    L
    Low (Singapore, SG)
    Quality Cable

    Love the weight and thickness of the cable. Improved the sound quality as well—fantastic customer service, responsive and accommodating.
    Area to improve - punch. Too small. Can't fit my IEM.

    D
    Darren (Singapore, SG)
    Great Quality

    Great quality upgrade to my stock cables, feels and look great, and incredibly quick shipping!

    M
    Michael Y. (North York, CA)
    Amazing Quality

    I've been using this cable for over a month and I'm happy with my purchase

    K
    K. Z. (Shanghai, CN)
    Nice upgrade for my Z06

    Compared to stock cable of Z06, the 8-wire version of Epsilon gives a good upgrade while not changing the original sound signature.

    I
    Ivan (Rancho Cordova, US)
    Incredible Cable

    I have cables that cost several hundreds of dollars and they pale in comparison to this. It is incredibly well made. Shipping was fast, too.

    Null Audio is going to be one of my go-to cable manufacturers going forward.

    B
    Bruno F. (Luxembourg, LU)
    Amazing cables

    Great looks, top quality and most importantly a noticeable improvement in sound quality.

    M
    Max H. (Vancouver, CA)
    Great cable

    My favorite cable ever. Nice and lightweight, and built super well. Highly recommended!

    R
    R W.C. (London, GB)
    Epsilon MkII

    I thought that my ThieAudio Monarch MkII IEMs deserved something better than the somewhat microphonic stock cable. As I had already benn delighted by my purchase of a Brevity for my Sennheiser IE600s, I plunged for the higher spec Epsilon. Good decision. Warm, enveloping sound with great comfort and ease of use.

    K
    Kyle K. (New Albany, US)
    Very Good

    I love these cables. This one is slightly warmer than my last Ethos which is what I was looking for. Really nice build and it is in black which is what I wanted.

    N
    Nico S. (Singen, DE)
    Amazing Quality&Service

    The cable looks and feels amazing. Customer service for a custom length was also a very pleasant experience. Bought it for my IE900 the connectors fit perfectly. I can only recommend this !

    Y
    Yiyang H. (Vancouver, CA)
    Great build quility and looking

    Bought it for my IE900. Best cable ever used so far. Building quility is super solid. Very premium looking with the new designing. Sound is fantastic. Definitlity will recommand to others.

    A
    Alexis S. (Vevey, CH)
    Beautiful product

    I bought the Epsilon Series Premium Upgrade Cable for my Hifiman Aryas. The packaging and cable is top notch. The only issue is how they fit, leaving a 1cm gap between the connector piece and the headphone. This doesn't seem to affect sound, but it is a little strange and unexpected.

    T
    TATSUYA T. (Yachiyo, JP)
    worth the money

    Null Audio won't fail you.

    F
    Florin P. (La Seyne-sur-Mer, FR)
    Epsilon Series Premium Upgrade Cable for Headphone

    Hello, first of all, thank you very much for your work! All redy IEM Sennheiser IE900 it's amazing IEM and now with your cable, every thing i'ts fabulous! Thank you again. I will buy a Epsilon balanced 4.4mm for IE900 soon.

    C
    Christopher F. (Dallas, US)
    IE 600 Upgrade cable

    This is by far the best upgrade cable for the IE600, the fit, size and sound quality are perfect.

    G
    G.K. (Atlanta, US)
    Absolutte Must have for IE600

    I was on the fence of returning the IE600 due to its absolutely lackluster performance from the headphone cable. No product should be that faulty. My friend convinced me to give them another go but to buy a null audio cable. Not only is the connection now solid and dependable, but the sound signature is everything I was expecting when I bought them in the first place. Cable construction is better than anything I have purchased, they are comfortable, high quality, and really fantastic across the board. Any more high end IEMs I buy, the first place I'm next is to build a cable through this website. 100% worth it!

    P
    Perinkolam A.G. (Singapore, SG)
    Epsilon Series Premium Upgrade Cable

    Great cable. No microphonics or memory and sound stage is wider too.

    M
    Martin T. (Clementi Housing Estate, SG)
    Epsilon Series Premium Upgrade Cable

    It bring warm to my IE600 especially for jazz music.

    M
    Mark B. (Los Angeles, US)
    Above and beyond

    Build quality top notch.

    G
    Graham A. (Los Angeles, US)
    USB-C cable clicking

    Purchased this cable with a USB-C DAC (ESS9280) and the cable has clicks and pops when using with usb-c devices. Seems to be defective, looking to get a replacement but support has been slow to respond and resolve the issue.

    Questions

    Good to know

    How long until it ships?

    Every Epsilon 5 Pro is built to order by hand in Singapore. Lead time is around 1 week.

    Will it fit my earphones?

    Choose your connector when you order. FlexiPlug lets you switch between 2PIN, IE300, A2DC, IPX, Pentaconn Ear and QDC 2PIN. If your earphones are modified or need a custom fit, contact us before ordering.

    Find the right connector for your earphones

    What is 6N UP-OCC copper?

    Copper of 99.9999% purity, cast by the Ohno continuous process in a heated mould. Its crystals grow long, to a hundred metres and more, so across the length of a cable the conductor is virtually free of grain boundaries.

    What does Type 2 Litz mean?

    A Litz conductor built in two stages. Eighteen enamelled 0.05 mm strands twist into a bundle, and seven bundles, one at the centre and six around it, are rope-laid into a conductor of 126 strands. Four conductors make the cable: 504 strands in all.

    Can I get a different length?

    Yes. Choose Cable length in the configurator above: set any length from 50 cm to 3 m in 2 cm steps. Up to the standard 1.2 m costs nothing extra; longer cables cost more, and the price is shown before you add to cart.

    For a length over 3 m, contact us or WhatsApp +65-8731-5476.

    Will the sleeve turn yellow over time?

    Epsilon 5 Pro’s black insulating sleeve is made for prolonged durability and yellowing resistance.

    What is the return policy?

    Any build you choose from the options on this page, at 1.2 m or longer, can be returned or exchanged within 14 days of confirmed delivery if unused and in its original packaging. Returns carry a 30% restocking fee and exchanges none; shipping is not refunded.

    Cables with an inline microphone and cables shorter than 1.2 m cannot be returned or exchanged for a change of mind. Faults are a different matter: every cable has a 1-year warranty, so contact support@null-audio.com and we will assess it.

    Read the full return policy