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Kevalin Audio is pleased to introduce a unique, highly effective digital noise reduction technology by Waversa Systems.

Customer feedback about the EXT Digital Isolators has been overwhelmingly positive. In fact, the flagship EXT Reference Plus LAN ethernet isolator has been adopted by its purchasers as essential in their digital systems because of its immediate, remarkable positive enhancement of all aspects of their digital systems’ sound quality - even to the detriment of adoption of other excellent devices from Waversa! For example:

Hello John, 

I believe I am ready to ship the SmartHub 3.0 back to you. I enjoyed what it does in my system, however it really did not increase sonic properties over what I already have. I did not experience the uptick in sonics compared to what the EXT Plus accomplished. 
I have built a very complex network/music streamer and adding additional components offer a minuscule improvement, this decision is based on cost/performance. I will say the Smarthub alone is a very good product, but in comparison of what I heard from the EXT Plus, keeping the EXT Plus is a no brainer. 
Please let me know what arrangements need to made for the return of the SmartHub... 



The Reference Plus

Which French Horn do you want to hear?


Waversa’s EXT isolators’ basic, breakthrough design is closely held by Waversa under patent protection. It is being used in military and medical applications where the “cleanest” of digital signals is required and home audio also benefits.

Essentially, the devices create “tuned” electrical and magnetic fields that negate RFI and EMI effects from interference caused not only by external radiation but also by transmission within cables themselves, as well as some carried within the actual digital “packets”.

The devices are:

⦁    non-directional
⦁    completely passive (no power supply is required)
⦁    do not sever the ground connection


EXT-1 LAN internal view

Best results occur with:

⦁    a short, no more than 12 inches (30cm) recommended, cable between the EXT and the following component
⦁    a fixed ethernet transmission speed of 100mbs
⦁    a quality RF/EM shielded cable to retain the purified signal.

(These generate minor but notable differences)

HiFi Club of Korea’s review of the EXT Reference includes an excellent description of the Reference and its sonic benefits, as well as discussion and measurements of digital signal overshoot, a problem creating noise that plagues digital transmission and, consequently, both analog to digital and digital to analog conversion results. Read the review here: HiFi Club of Korea review of EXT Reference (translated)

Each isolator comes with its own short cable sourced from third parties. You may have your own preference; the key is to keep the cable short, as noted above. Waversa manufactures in-house its own very high-quality “VSHIELD” Ethernet, USB and Coax (RCA, BNC, AES/EBU) cables.

Waversa makes 30cm, 60cm, and 1.8m versions of these cables. They make only these limited lengths as their tests indicate any other lengths cause issues with internal reflections and, therefore, distortions. 

WVSHIELD Technology
There are variations among these Waversa digital cables, mainly regarding the metals of which the conductors are made and the construction and materials of the terminations. In general, however, VSHEILD is a Waversa Systems advanced technology that fundamentally protects a signal from the inflow of noise generated by the housing of the cable. Although some of these technologies have been adopted in high-speed RF transmission, Waversa has further enhanced this design to minimize the effect of noise on the audio signal. VSHIELD involves a copper shield on each wire, not simply the winding an expander around an existing cable. This makes the background quieter, the contours of the bass more clearly defined, with the highs reproduced smoothly without any hesitation. To manufacture VSHIELD cables, Wavera Systems has even developed and produced a dedicated device used to create the wire shielding through the painstaking process of hand-crafting these cables.


EXT Reviews to Date:

In addition to HiFi Club of Korea’s above referenced and linked review of the EXT Reference isolators, their review of the EXT-1 is also well-worth reading: HiFi Club of Korea EXT-1 Review (translated)

The first professional North American review - of the EXT Reference - appeared in October in Stereo Times: Stereo Times Review Waversa EXT Reference October 2022. To keep it short here, reviewer Mike Girardi concluded, enthusiastically and emphatically:


I have chosen the Waversa EXT Reference to be an integral part of my digital streaming system and will nominate it for a Stereo Times Most Wanted Component award.

Highly recommended.



Consumer Feedback:

When I first saw reviews of the Waversa EXT it piqued my interest. When I called John Ketcham to inquire about the unit he noted that many users retained and purchased their units after being given a ‘test run’. John suggested that I try the Waversa EXT Reference Plus as it would be a good match for my DAC and streamer. The unit arrived in short order and was easily and quickly installed.


Giving it the usual pause, I sat to listen expecting the usual hours of comparison of having to take the unit in and out of my Ethernet source. Boy was I surprised! Within mere seconds there was an immediate and very noticeable difference.  Not the usual ‘difference’ but a huge positive improvement in all areas. What I immediately noticed was better control and delineation of base, much wider soundstage with greater depth and instrument delineation and positioning. I should note, all of this is delivered in a totally natural way, without any hint of over emphasis or exaggeration. Totally real!


I never realized that the output of Ethernet could be so corrupted by RF and EMI and more importantly, have such a negative impact on the resulting sound. Astonishing! This single device has transformed my digital source. I can totally recommend the Waversa EXT Reference Plus without any hesitation. This is a truly remarkable product!


D. R.


The Reference plus is amazing! Somehow it removes 'digital' distortion (that I didn't hear before) ... increased tonal purity, lower noise floor and real 3-D.


D. A.


More playing around... Ref Plus is better than daisy chained References. How to describe it... everything a pair of Refs do but more "drive"(immediacy?), "attack", "richness" of harmonic structure of every instrument, separation of instruments and voices but keeping "musicality" - I've never had such a sense of musicians, stage, alive in front of me - 'like in the studio' says my drummer friend... with the addition of the Ref Plus the air in the room is alive with the vibrations of the instruments' wood, wire, brass - with the breathing presence of the vocalist(s). Absolutely lovely. Use the short Waversa in-house built cable for best result.


A single original isolator is a lovely enhancement; a single Reference builds on that, providing more air, separation, stage, articulate bass; daisy chained References more than double those effects, opening-up and enlivening everything; the Plus is transformative.


G. S.


To order, please follow the link to the device’s product page on this site or call/email me, John Ketcham at Kevalin Audio:
1-503–292–5592 /

If you’re in Canada, contact Bob Suwary at Watchdog Digital & Analog Solutions
1-416-844-1072 / 


Prices for Waversa’s EXT digital noise isolators:

(Subject to change without notice):

⦁    EXT-1 (Ethernet, USB) Special Order: Coax, BNC, AES

(Introductory price.  $1,000 List: $1200)
 Link to product Page

⦁    EXT-1 (HDMI)                  $1,200

⦁    EXT REFERENCE (Ethernet, USB, Coax, AES, BNC))        $4,950

⦁    EXT REFERENCE PLUS (Ethernet, USB, Coax, AES, BNC))        $14,250

⦁    Waversa short LAN ethernet cable:   30 cm $600, 60 cm $750, 1.8 M $900.

⦁    Waversa short USB cable:   30 cm $600, 60 cm $750, 1.8 M $900.

Photo Gallery:

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