KLEI Silver Harmony RCA

KLEI Silver®Harmony RCA Plug Review

Well, it seems like the guys at Keith Louis Eichmann Innovations liked my
KLEI Copper®Harmony RCA Plug Review so much, that they sent a pack of their new KLEI Silver®Harmony RCA plug, which is the middle entry in their KLEI Harmony®Plug line.

Visually, the only thing to distinguish between the KLEI Copper®Harmony and the KLEI Silver®Harmony is the colour of the logo on the collar, as can be seen below.


Since I found the performance of the KLEI Copper®Harmony RCA Plug to be so good, I asked the question:
  • what would make the consumer opt for the more expensive KLEI Silver®Harmony RCA Plug?

The KLEI response:
KLEI™Copper Harmony plug
  • Proprietary mathematical modelling optimises mass, thickness, and composition of the conductive pins to enhance electron flow, incorporated in accordance with KL’s proprietary Copper Signal/Ground formula, where extrapolated results are even >102% IACS.
  • The conductive pins incorporate highly conductive materials, such as copper and silver.
KLEI™Silver Harmony plug
  • Proprietary mathematical modelling optimises mass, thickness, and composition of the conductive pins to enhance electron flow, incorporated in accordance with KL’s proprietary Silver Signal/Ground formula, where extrapolated results are even >105% IACS.
  • The conductive pins incorporate highly conductive materials, such as copper and silver.

What is IACS again ?
— it’s a measure of the conductivity of various metals relative to “Pure Copper”, a standard developed for copper wire producers, having a rating of 100%

- See
IACS Conductivity Ratings PDF for further details.

When I asked what performance improvements to expect from the Silver®Harmony, the KLEI response was:

  • They bring out even more of the details, dynamics and improved imaging obtained using the KLWI Copper®Harmony.
Now the KLEI Copper®Harmony had performed well above my expectations, improving on my original Eichman Silver Bullet RCA’s by a considerable margin and taking their place as my new reference standard, but were the KLEI Silver®Harmony RCA’s capable of repeating that level of performance improvement?

The Prep Work...
In preparation for this review I had taken KLEI at their word, that the KLEI Silver®Harmony would reveal more dynamics and details. So, whilst waiting for their arrival I decided that in order to perceive such benefits I might need to do a couple of things
  1. Upgrade the power cables on the source components and amplifier - a little extreme you think? Well, I was in the process of completing this when I received the first email from KLEI asking me to review the KLEI Copper®Harmony, so that was put on the back burner until the review was complete.
  2. Find some additional tracks that I thought might just reveal the performance improvements mentioned above

Thankfully, the KLEI Silver®Harmony took a little while to arrive, which gave me ample time to install and burn-in the new power cables, get accustomed to the new sound and select a few tracks that sounded that they might provide the required details and dynamics.

During this process it became quite apparent just how good the KLEI Copper®Harmony really are: their delivery of exquisite detailing, spacious imaging and very fast dynamic response was clearly audible in my system.

SIDEBAR: Some Third Party Feedback...
During the time the KLEi Silver®Harmony were in transit, I had the opportunity to exchange experiences with another person that had tried them.

Their initial findings (i.e. before complete burn-in) were completely different to my own experience with the KLEI Copper®Harmony, in that they thought the KLEI Silver®Harmony sounded “boring” which I took as “lacked in dynamics”, the upper frequencies appeared to “roll-off” very quickly and they did not experience the blooming of bass frequencies as I had.
  • I believe this is a good indication that the effects a person encounters during burn-in will vary when used on different cables.
  • They did confirm that after a longer burn-in period (100+ hours), the KLEI Silver®Harmony had outperformed the KLEI Copper®Harmony, citing better image, dynamics and details.

Cut To The Chase…
Well - the proof of the pudding is, as they say,
“in the eating”.

So once they arrived, I installed the KLEI Silver®Harmony onto one set of my Stager Silver Solid interconnects and started the burn-in process.

As with the KLEI Copper®Harmony, I allowed for approximately 150 hours burn-in time, with small mini-auditions performed at approximately 24 hour intervals.

What I experienced within the first hour was almost identical to what I had experienced with the KLEI Copper®Harmony:
  • Immediately, I notice a significant improvement in imaging and dynamics
  • mid-frequency details were initially very good - about on par with the KLEI Copper®Harmony after burn-in
  • high frequency details were much improved and extended
  • Again, there was a significant “blooming” of certain upper-bass frequencies
  • there was a new depth to the bass frequencies that was also very muddled and bordering on distorted

Just as with the KLEI Copper®Harmony, the character of the KLEI Silver®Harmony changed significantly for the better as burn-in progressed
  • On Eric Clapton’s album Clapton Unplugged, the stomping of his foot on stage started out even more nauseating, due to the extended depth to the lower bass frequencies. But just as before, after burn-in the bloating simply melded into the background and became an integral part a very good live album, which also displayed even more details, especially in the vocals. On tracks Running on Faith and Walkin’ Blues, where, thanks to the extended upper frequencies, the use of the bottleneck throughout the track is perhaps the most realistic reproduction I have ever heard.

  • On the track You Look Good To Me from the album We Get Requests by The Oscar Peterson Trio, not only could I hear Ray Brown humming his intro, but there was a significant improvement in the details, such as the vibrations the strings make against the fingerboard of the bass, which previously was quite muted and now the superb textures in the triangle at the beginning of the track were very audible.

  • The Cymbal work on Staple It Together, from the Jack Johnson album In Between Dreams had a much faster attack from the initial strike and the decay was longer than that experienced with the KLEI Copper®Harmony.

To challenge the dynamic presentation I selected some new tracks that I thought would be more revealing that those I had selected for the KLEI Copper®Harmony.

The first was
Precious, from the album Diva by Annie Lennox
  • Annie’s voice has a superb “brittleness” to it and the KLEI Silver®Harmony provided the edge required to highlight that trait.
  • The base line had a deeper presentation, but also an extended level of control that brought out never before heard texture and the improved dynamics gave the track some additional slam not perviously experienced.
  • The improved detailing also made the opening chord sequence on the electronic keyboard much more revealing of the textures that had been recorded.

Another track that made me sit up an listen was
Turtle Shoes, from the album Don’t Worry Be Happy by Bobby McFerrin.
  • For those of you unfamiliar with his work, Bobby McFerrin multi-tracks pretty much all the vocals himself, with some amazing sound engineering that captures his percussion line which is derived from him pounding and slapping on various body parts - he also has a very edgy vocal when deemed necessary and again KLEI Silver®Harmony allows those extremely fine details to be heard.
  • There is depth to the percussion line that is extremely textured, but since the focus is very much on the vocal performance you are also able to hear every delicate nuance of this talented performers considerable vocal talents.

From the album
The Police - Greatest Hits album I had selected Walking On The Moon
  • Primarily because I thought that the opening quitar chords would highlight the KLEI Silver®Harmony’s dynamic prowess and I was not wrong.
  • But better still, the details in Sting’s voice and the textures in his bass line reinforces the amazing abilities of this diminutive little RCA plug.

I’ve used words like “edgy” and “brittleness” to describe how the KLEI Silver®Harmony enhances micro details and combines its extremely fast dynamic abilities to reproduce those traits.

But initially, I had wondered if this new edginess was due to distortions that had not
“worked themselves out” during burn-in.
  • To verify that this was NOT the case, I returned to a track previously used in the Copper®Harmony review, the Violin Concerto no. 4 in D major KV 218 - Allegro by Marianne Thorsen / Trondheim Solistene.
  • If there were distortions in the signal, then the violin on this track would likely reveal them.
  • Instead, the violin came across smooth and extremely detailed with a more spacious image that is wider, deeper and with a more precise placement of the musicians within the space.
  • What you hear more of are the extremely fine higher frequency micro details, such as those found in the reproduction of cymbals, having a very fast attack of the initial strike, followed by a long decay, both of which has body and texture.
  • Sibilance now has considerably more texture and depth and is silky smooth.
  • The sound the KLEI Silver®Harmony conveys is full bodied and full range and is definitely NOT “thin” or “bright”.

Thinking back to the KLEI Copper®Harmony review, a track that I believed would demonstrate how much more revealing these RCA plugs are is
Iberia: Debussy - 3rd Mov’t - London Symphony, Andre Previn conductor.
  • The first thing I noticed was the extended width of the image, now considerably wider than the distance between the speakers.
  • There is without a doubt more details, particularly from the percussion section that is placed even further back in the image, but without loosing any clarity or volume.
  • The tambourine had much more pace to it and the castanets had a more life-like “clack” to them

One of my favourite newly selected review tracks is
With You In Mind from the album Blue Chip, by Acoustic Alchemy, selected because of the extraordinary sound engineering and musicianship. It’s a very easy track to listen to because there is not a cacophony of instruments vying for your attention and distracting you from the details.
  • Just a couple of guitars, a little subdued percussion and some nice melodic slide guitar way in the background. And that’s where the KLEI Silver®Harmony’s excelled, delivering a crystal clear reproduction containing the very subtle micro details of the strings being plucked and the buzzing of the strings on the fretboard and as their hands move up and down the neck the unmistakable rasping of fingers sliding over the “round-wound” strings.
  • Perhaps my playing guitars for many years has made my ears more “receptive” to these sounds, but it still takes a very adept system to reproduce them with such startling realism and clarity, which left me believing the KLEI Silver®Harmony has without a doubt made a significant contribution to my systems performance improvements.

At the other end of the frequency range is added depth in the lower bass frequencies with considerably more control. This was very evident on
Más, from the album Mi Plan by Nellie Furtado, which has some of the deepest synth work in my collection and another track from the same album, Vacación, where the thump of the bass drum is very deep and superbly controlled. In fact, the entire album highlights the amazing dexterity of the KLEI Silver®Harmony

My observations above were made while using the Interconnect to connect the analogue outputs from my DAC to my Amp. I then used the exact same interconnect to connect my phono stage to the amp and listened to several tracks from multiple albums.

To my surprise I found that there were even bigger improvements in image, dynamics and details. It seems that the KLEI Silver®Harmony are an even better match for my phono stage than the KLEI Copper®Harmony.

I have not found any downside in using the KLEI Silver®Harmony on my Stager Silver Solids Interconnects, other than a slightly longer burn-in period that approached 185 hours to reach their full potential. Across the board they perform exceptionally well, providing an image on orchestral tracks that is so deep that a little additional volume is required on some older recordings that were performed in very large venues.

The response from KLEI posted above was spot on - more of everything, but in a very balanced presentation that does not accentuate any part of the audible bandwidth.

In the case of the
KLEI Copper®Harmony I summed up their performance in one word - Clarity

With the KLEI Silver®Harmony, especially on acoustic tracks and classical ensemble tracks, it is like being at a live performance.
  • On live albums the applause has body, instead of sounding like a game show contestant getting the right answer.
  • When Eric Clapton talks between songs you just had to close your eyes and he was right there in the room.

A technique I often use to gauge how well my “tweaks” or “upgrades” are performing, is to stand or move around in the hallway outside my listening room.
  • Why? - it removes distractions such as “spatial image” from the equation and allows me focus solely on the acoustic attributes of the sound
  • I find the timbre of an instrument or the subtleties in an artists voice to be much more revealing and allows the realism in the recording shine.

In the case of the
KLEI Silver®Harmony they transcend clarity - they are simply - Transparent

The transparency of the KLEI Silver®Harmony makes them the closest thing to “3D glasses” for two channel audio I have experienced to date.

That is - until I review the
KLEI Pure®Harmony - stay tuned - coming soon Happy

The price of the Silver®Harmony? - $90 for a set of 4 (from Parts Connexion)

The details on the
Silver®Harmony, including Australian pricing, is available on their web site at...


They are also available in North America from
Parts Connexion


Ever get that
“smile of satisfaction when something very right is happening” ? - ME TOO! Happy

The KLEI Silver®Harmony RCA, when used with high performance interconnect cable, conveys an incredibly detailed analogue signal that results in a very realistic three dimensional reproduction of recorded music, regardless of whether it originates from an Analogue or Digital source.

One question that came up recently - Can the KLEI Harmony®RCA Plug range be used for Digital interconnects?

  • I have not tried them as yet, but plan on doing so soon.
  • I have read a review that cites exceptional performance improvements over one very expensive purpose built single ended digital cable.
  • I have also exchanged several emails with KLEI on this topic and it appears that due to the high impedance of the entire KLEI Harmony®RCA Plug range (i.e. >110 ohms), they do not degrade the transfer of a digital signal between components.
  • This however, can be a problem with the more conventional RCA designs, where, if not matched exactly to the impedance of the cable, can result in internal distortions and jitter, causing poor sound quality.

Until I actually try them, I can only offer an “opinion”, but having experienced the speed and dexterity of their analogue performance I would have to conclude that the KLEI Copper®Harmony or KLEI Silver®Harmony, when used for digital interconnects utilizing 50, 75, or 110 ohm cable, may well result in the near elimination of jitter caused specifically by interconnect-component interaction and component transmission & reception issues, resulting in a significant improvement in the analogue performance of most current day DAC designs.

In some quality digital products, performance may even transcend the
"digital realm" and possibly achieve the much sought after "soul of analogue".

And YES - the KLEI Silver®Harmony are my new reference RCA connector!

But it’s not farewell to the KLEI Copper®Harmony just yet - I’ll try them on a very good digital interconnect I have - so check back in a couple of weeks Happy

UPDATE: As planned, I transferred the KLEI Copper®Harmony to one cable in a pair of “The NAME”, a 75 ohm interconnect from Van den Hul.

Removing the existing RCA’s from “The NAME” revealed that they were in fact very well made RCA’s that appeared to have been matched ,from an impedance perspective, to that of the cable. Not that I can tell that for certain, but the construction approach appeared very similar to that of quality BNC connectors.

Attaching the KLEI Copper®Harmony to the much thicker centre conductor and the braided shield of of the 75 Ohm cable was a little more difficult than my 24 gauge solid silver interconnects, but much easier than the Silver Bullets and once the housing was in place and the small set screws were tightened onto the 7.3mm diameter cable it provided very good support.

To test the cable I reinstated my Pioneer Elite DV-45A DVD player with SACD capability, Unfortunately SACD playback is only available via the players analogue outputs, so the de facto digital standard for the purpose of this review was going to be the 16/44kHz digital stream via it’s s/pdif output, which in turn was connected to my Schiit Bifrost DAC

However I was able to easily perform an A/B comparison with the exact same tracks within my iTunes library on my iMac that is connected to the same Schiit Bifrost DAC via its USB-2 asynchronous interface. My iMac also uses Audirvana for final digital transfer to the DAC, in order to bypass the vastly inferior Apple audio routines that alter the digital content before transmission. So the “data” being transferred is what resides in the actual music file - nothing added!

Several tracks of varying musical styles were auditioned, several times each in fact and I can report that I could not tell any difference between
  • the digital stream from the DVD player’s s/pdif output using the Van den Hul “The NAME” interconnect with the KLEI Copper®Harmony RCA’s
  • the digital stream from the iMac via iTunes/Audirvana using a USB digital link.

I did also manage to play some music DVD’s that contain 24/96kHz tracks, but alas the DV-45A down samples to 16/48kHz, so that was the best sample rate I was able to test with.

There were no signs of jitter, and playback was very smooth, spacious, detailed and dynamic, which supports the claims of KLE Innovations, that the KLEI Copper®Harmony and KLEI Silver®Harmony are also very capable performers when used on digital interconnects.

I did switch over to the other Van den Hul interconnect that is terminated with VDH’s own RCA’s and by comparison. There was a very slight degradation in high frequency details, most noticeable in the smoothness of the presentation of cymbals and sibilance.

One reviewer, with a digital front end capable of higher sample rates than my own, was very surprised to find that a cable he constructed himself using the KLEI Harmony®RCA plug, performed better than a very expensive interconnect he owned.

So, if you find your digital components are not performing to your satisfaction, give the Harmony®RCA plugs a try.

You might be pleasantly surprised.

page6_blog_entry40-two-thumbs-up A highly recommended product!