Jomo Audio 6R


Headphoneus Supremus
Pros: It is very clear, has great detail retrieval, relatively transparent. It seems fairly even in tuning, reference level.
Cons: not for bass heads

JOMO Audio 6R Universal IEM Review - Expatinjapan

Reviews are hard work, they take time. Endless critical analytical listening sessions looking for what is broken and also what works takes its toll when one just wants to listen to the music.
Thankfully high end and low end earphone models take the least work, its the ones in between that require the more razor sharp attention to detail as the problems can be harder to spot.

Luckily for me the JOMO 6R is at the high end of the continuum line.

Coming off the back of the Campfire Audio models that I recently reviewed and enjoyed it did take a while to wash their sound signature out of my ears and to be able to approach the reference JOMO Audio 6R with fresh ears.

In short it was a pleasurable experience.

Thanks again to JOMO Audio for sending and gifting me the 6R.

Lets start with the basics, or you eager beavers can do your usual trick and skip to the sound section.


The JOMO Audio 6R comes in a sturdy internally padded case with a hard plastic outer.
The IEMs lie in wait inside, secure, protected and safe as houses.
IEMs and cable tied with a nice JOMO branded velcro tie.​
Wonderful detailing in the construction of these IEMs.​
The cable is high performing, but I would like to see another design to match the beauty of the IEMs.​
Nice well crafted IEMs without bubbles in the acrylic molding.​
Each ear piece inscribed with `Jomo, review`.​
The cable itself is light, has a right angled plug and is not prone to tangling.​
The Jomo 6R comes with a metal card with the owners (me) information on it and the units information, assorted tips (short double flanges), a cleaning brush, an airplane adapter plug, a 3.5mm to 6.3mm adapter and a carabiner for hanging the case from a bag or belt.

The build is hand made, each individual unit crafted and checked for any imperfections.

The JOMO website has multiple drop down menus where you can craft and design your desired IEM to your particular preference. Don`t let the opening pictures on the website initially fool you, click on the customization tab for the many options to style the IEM to your liking.

The unit crafted for me by JOMO Audio is acrylic with an ebony wood inlay, combined with watch parts for a steampunk effect.

Each ear unit has 3 bore holes in the metal nozzle.

The nozzles are quite large in circumference and might not be ideal for small ears.
I am using medium sized tips and they easily slide right in for me, just fitted.
Jomo 6R nozzle circumference next to Campfire Audio.​
NOTE* Remember I requested an extra long nozzle length.​

Certainly they are sturdy, they feel solid and light in my hands.
Of course one must always take care of such earphones as the drivers inside are delicate.
I requested long nozzles as I have had trouble with some other IEMs getting enough depth for a secure fit and isolation. JOMO obliged.
I have been through the supplied double flanges, Spin fit (not recommended, lessens the bass), various sizes of JVC spiral tips and Ortofon, and have settled for switching between the supplied double flanges and the Ortofon tips.
Repeated from the build section: The nozzles are quite large in circumference and might not be ideal for small ears.
I am using medium sized tips and they easily slide right in, just fitted.
  The JOMO IEMs such as mine prefer and perform better with a more open tip rather than a narrow bore tip.
Jomo Audio:  "Now the universals are all pre-made with complex designs. We don't focus on universals. Only when we have got time we will make a batch of universals. But each and every batch has different design and we will not reproduce the design".
Impressions, 1.
Early impressions were positive, yet the usual findings of a slightly bright treble and receded bass signaled that as usual I needed to get some hours on the JOMO 6R to even out the initial teething issues that seem to occur with most earphones.
As time went by bass became more present and the treble became more controlled.
It is very clear, has great detail retrieval, transparent.
It seems fairly even in its tuning, reference level.
  Impressions, 2.
The JOMO 6R are beautiful to look at and also to listen to.
They have a great transparency, are a reference type of earphone that favors neither the lows/mids or highs. 
Detailing is exquisite and not artificially induced by treble trickery or other such hijinks.
*From Head pie`r r3n88 owner of the Jomo 6R, he writes: 
Adele's "Remedy" is emotional and moving. The stretch of her breaths are clearly depicted. 
The 6R's tuning is linear and balanced with a very smooth presentation. 
Bass is quick and controlled that's a bit lacking in energy. 
The 6R possesses an impressive sense of resolution in its imaging that feels like a fine-tuned IEM".​
Jomo 6R with COWON Plenue S.​

Review and summary -back to expatinjapan/Damon.

I ended up with around 200 hours of playtime/burn in on the Jomo Audio 6R using various genres of music and burn in tracks of different frequencies.

The Shozy Alien Gold Dap, Centrance Hifi-Skyn with ipod touch 6G, 128GB with Flacplayer app and also the OPUS#1 Dap were the sources used.

In the end the synergy I decided was the best was with the OPUS #1 Dap.
The performance of them all were incredibly close yet the OPUS#1 slightly edged them out on micro details, height and width.
I tried out many genres of music to get a clear overview of the performance of the JOMO 6R, either listening to whole albums or using shuffle mode (pictured above) to cut down on general familiarity of my usual choices and add an element of surprise to my listening/testing sessions..
I tried out several tips and thought that the supplied short double flanges (S/M/L) or the Ortofon tips were best suited to retain the intended signature of the JOMO 6R.
In the end after the initial burn in had been completed and the Jomo 6R settled down to perform in the manner expected of it as a reference styled and tuned IEM my later findings remained consistent with my earlier impressions, only with more present and tighter bass, controlled highs and an even mid section.
The JOMO 6R when paired with appropriate flat Daps presents the music as recorded with virtually no coloring as such, well,... reference as promised.
It performed well with the sources/Daps I used in my testing but the added detail retrieval the OPUS#1 provided determined it to be the best match to my ears.
The JOMO 6R is a joy to listen to, after the main burn in any imperfections in delivery were harder to trace without minute nitpicking which would be more about personal aural preferences than the actual performance of the Jomo 6R.
It is a clear reference level IEM with wonderful clarity and detail when playing softer tracks with strings, vocals and smaller drums, the 6R also responds well when more stronger music with loud guitars and strong vocals are thrown into the mix.
The JOMO Audio 6R delivers on its reference IEM promise. Presenting an IEM that has great micro detail, bass that is fast, tight and yet lovely in a lush sense, impeccable layering, well balanced mids that sit just right, treble that is sweet, reaching and not over extended, shrill or sibilant.
Vocals are accurately reproduced and remind me of my record album listening days of yore.
The JOMO 6R has excellent instrument separation, a wide sound stage and generous width and height yet communicates the above to listener in quite a natural and organic sense. More analog than overly digital.
Jomo Audio offers several models starting from their single driver US$215 model and then going up wards from there.
The JOMO 6R clocks in at around US$1,015.

Thats a lot of nest egg to drop on a pair of IEMs, is it worth it? As usual price, affordability and value is often a personal thing.
The main accurate question perhaps would be `Is the Jomo 6R in the same league as other IEMs in the same price point?`. From my limited opinion I would say yes.

The JOMO differ in that they are more hand crafted than other more assembly manufactured IEMs.

From the JOMO website:

"The R series monitors aim to have a flat response for reference monitoring. 
Six Precision Balanced Armature Drivers
Single Dual High, Dual Single Mid and Single Dual Vented Low configuration
Advance horn sound outlet design*. 
Three way passive crossover network. 
FR: 20Hz - 20kHz
Sensitivity: 126dB
Impedance: ~20 ohms
Noise Isolation: 26dB +/- 3dB(Custom Version)
*Horn sound outlet design depends on the size of the ear canal portion. When the ear canal is not big enough for three sound tube to be recessed in a horn sound outlet design, a flush sound outlet will be built. JOMO Audio reserve the right to decide if a horn sound outlet is possible. "

Aftermarket cables

I tried the JOMO 6R with several quality two pin aftermarket cables without much the success.
The supplied cable was the best match I found.
I do have another cable on the way which I am informed is a good match for the 6R, we will wait and see.
Synergy plays a big part in achieving aural bliss.
The JOMO 6R is a high performing IEM that is best suited paired with an upmarket DAP for best results.
It performs its function as a reference tuned IEM wonderfully, presenting and accurate representation of the music fed to it.
It ticks all the right boxes of height, width, instrument separation, detail and micro detail, soundstage and layering.
Hiss is minimal from what I can gather, although do note that I am not particularly sensitive to hiss and also listen at generous levels.
If you are looking for an energetic or V shaped sound signature the JOMO 6R is not for you, If you were after  `linear and balanced with a very smooth presentation`(- r3n88) you would find satisfaction with the 6R.
Build is impeccable, although I would like to see a sexier cable to match the wonderful construction and look of the gorgeous IEMs themselves.
It is very clear, has great detail retrieval, relatively transparent.
It seems fairly even in tuning, reference level.
Great pie!
Thank you to JOMO Audio for sending Head pie a review unit of the JOMO 6R IEM​


Headphoneus Supremus
Pros: Exceptional clarity from a highly neutral sound signature without an artificially bright sound, easy to drive, beats the original UERM
Cons: High frequency reproduction very good but can't compete with Stax, very focused sound equals limited soundstage size
Custom In-Ear monitors. I love 'em. There's nothing quite like the experience of a custom-molded, perfect-fitting IEM which practically melts into your ears. I can listen for hours without fatigue, and on the rare occasion where I use a universal model, I'm inevitably uncomfortable within a half hour or less. Then I switch back to a good CIEM and all is right with the world once more. I realize that aspect is different for everyone - some people get along just fine with universals, so it's definitely an individual preference.
I recall the early days of custom monitors. Back when they were primarily considered tools for musicians and their supporting staff of engineers etc. You think custom IEMs are costly now? Roughly a decade ago, I paid nearly $1,000 for the Ultimate Ears UE-10 Pro, a triple driver model which at the time sounded fantastic but is absolutely nothing special by today's standards. Nowadays that level of performance can easily be had for quite a bit less, from one of the many, many brands making custom monitors. Back then we had UE, Sensaphonics, and Westone as the main players, with a few lesser known brands floating about in certain regions. Today there are dozens and dozens of CIEM companies which in my mind is a great thing: more competition, more options, and a better chance at having a local firm - you may even be able to visit in person. The only real downside is keeping track of them all.

One of those many brands is a company called Jomo Audio. Based in Singapore, Jomo is the brainchild of Joseph Mou (get it? Jo Mo?) who has worked in the broadcast industry for years. While handling equipment installation and related tasks for TV and radio stations, Joseph found himself infatuated with IEMs. It started with universal models from the usual suspects like Shure, but the engineer nature proved too strong. One thing led to another, and after much research (and money spent) Joseph had "made" his own custom IEMs - though it would probably be more accurate to say he had reshelled an existing universal model. But he wouldn't stop there.
This is where Joseph joins the ranks of John Moulton (Noble Audio) and Piotr Granicki (Custom Art) - passionate enthusiasts who couldn't leave well enough alone and just had to make their own custom IEM designs from scratch. He became active in the massive Home-Made IEMs thread as well as other threads on local forums. Things progressed until mid 2015 saw the launch of Jomo Audio, primarily serving his home region but eventually branching out across the globe. 
Now, I've never personally traveled to Singapore, but word on the street says there's a plethora of audio shops, in which one can demo practically any headphone in existence. I specifically asked Joseph about rival brands and he told me he could drive less than 30 minutes to find Ultimate Ears, Westone, JH Audio, or any number of other brands. This is a blessing and a curse - it helps him know where his designs stand in relation to established firms, but also makes life hard for a startup due to the extremely competitive nature of the local market. 
One solution is to sell at rock bottom prices. Become a derivative brand, or sell reverse engineered UE and Westone designs for dirt cheap. I've seen those sorts of operations come and go on Taobao and other markets. It might actually be a profitable endeavor but isn't likely to satisfy someone who has a passion for designing their own stuff. Joseph figures the way to stand out is to offer excellent craftsmanship, beyond what most others are capable of. That, combined with excellent customer service and a robust line of great sounding IEMs, should leave a trail of satisfied customers large enough to attract some buzz. So, while Jomo's prices aren't the lowest you'll find, they certainly aren't the highest either, and the company aims to give an "experience" on par with the best out there without charging top dollar. That's the theory, let's see how well it works.
The Lineup
Jomo offers a range of products starting from a single-driver design all the way to the upcoming Samba 8-driver model. Under review today is the current flagship of sorts, the Jomo 6R - there's also a non-R Jomo 6 using different drivers and different tuning, with a slightly lower price. Joseph tells me the 6R design was 8 months in the making, inspired by pleas from local musicians and audiophiles wanting a clear, highly resolving sound which could be easily driven even from a low power source. The 6R starts at $1399 for the standard configuration and moves up to $1649 for the "deluxe design" package which opens up all sorts of possibilities for exotic looks. Keep in mind those prices are in Singapore dollars, which at the moment translates to $1043 to $1229 USD. So, roughly in line with what I've come to expect as the general price-range for upper-level custom IEMs, though I'd say that average is on the rise thanks to some other brands.
The 6R is at present the sole member of Jomo's "Reference" line. The stated goal is to give a flat response suitable for "reference monitoring" - whether that term appeals to working professionals in the music industry or just to enthusiasts unwinding after a long day is open for debate. Jomo claims the design delivers "crisp sound" so the listener "will not miss a single note". Slick marketing is not really Jomo's strength but I'd say this is an accurate description of the 6R experience. 
The design uses 6 balanced armature drivers, likely from Knowles Acoustic since Joseph mentioned their name during our discussion (it helps that they remain the largest and most common provider of BA drivers, so the odds are in my favor). 6-driver designs are pretty much ubiquitous these days, often but not always positioned as the flagship in a brand's fleet. Yet there are many different ways to do a 6-driver IEM. Jomo's design uses a single dual-high driver, a pair of individual midrange units, and a vented double-low driver for bass, with frequencies routed via 3-way crossover. The tip features what they call an "advance sound horn outlet design". This can be seen in my pictures - it's hard to explain but easy to understand just by looking. This is a classic horn design as used in many speakers, as well as some models from Westone, Rhines, and Vision Ears. The main goal is to improve high frequency response allowing better clarity and detail to come through. A nice side benefit is the resistance to clogged sound tubes.... earwax has a far smaller chance of getting wedged in the tube itself, since there's a buffer of sorts standing in the way. Worth noting: really small ear canals will be unsuitable for the horn tips, and in that case a more typical flush design will be used. I won't speculate as to how that might impact the sound, since my large ears had no problem accommodating the horn design.

Jomo rates the 6R as having a 20 ohm nominal impedance. As always, that doesn't paint the whole picture. In this case the curve is fairly benign, mostly flat with a small peak in the 2.5kHz range and then steadily climbing until it hits roughly 40 ohms at 20kHz. Driving the 6R with a high output impedance will impact the sound to some degree but nowhere near as drastic as the Shure SE846, Ultimate Ears UE900, or NuForce Primo 8, to name just a few designs with wild impedance swings. 
With a sensitivity of 126dB, plus the relatively easy to work with impedance curve, the Jomo 6R definitely meets its goal of being easy to drive. It's a resolving IEM that does benefit from a really clean source, but pleasing results can be achieved from simple things like the iPhone or a Sansa Clip. Hiss can be a problem with some DAPs - not to the point of being completely unlistenable, but I do question whether the increased general fidelity is worth the trouble over just using my smartphone. At home, it's the same deal with desktop amps, many of which are unsuitable to the task due to high gain and general noise with sensitive IEM use. My MacBook Pro and Surface Pro 3 both gave very enjoyable results straight from their headphone jacks, to the point where I would rather use them alone unless I happened to have one of the few devices handy which could give a similarly clean, quiet performance. Seriously, as much as we tend to look down on more pedestrian sources and brag about our expensive gear, the Jomo 6R really doesn't need much to perform very well. I'll discuss this more soon enough.
As you can see from the pictures here, my particular 6R is pretty extravagantly designed. I just let Joseph go wild and make whatever he wanted, and the result is described as a "ribbon faceplate with starry black shell". Build quality is very high if not quite to the level of a Wizard Design product from Noble Audio. You can see other designs HERE - Jomo has plenty of interesting builds on display. 

One area where I'd say they still lag behind is the ordering system. While Noble, JH Audio, and Unique Melody have websites giving a clear breakdown of available options, the Jomo site is fairly simplistic. I get the feeling you'd end up describing what you want and hoping for the best, or perhaps sending a picture of an existing CIEM you found online to see if Jomo can do the same for you. Which is probably fine, but I would expect the website to improve as Jomo grows. 
Let's talk about the most important aspect of any IEM - the sound. The 6R is described as being exceedingly neutral, and I do agree with that statement in general. Problem is, everyone has their own take on what "neutral" really means. Obviously the goal is a flat presentation with no obvious peaks or valleys, but even within that framework there's still room for variation. Is the HD800 neutral? Some say yes, while others say it's too bright. The Etymotic ER-4S? The Stax SR-009? Same deal in both cases. Personally the most neutral sounding "headphone" I've used is the Stax SR-4070, which I feel is even more uncolored than their flagship SR-009. It's not always the most pleasing choice for regular listening but Stax designed it as a "monitor" earspeaker and I have to admit they achieved that goal nicely. 
The Jomo 6R sounds remarkably similar to what I hear playing the SR-4070 through my hot-rodded KGSSHV. Both have a flat, neutral response with excellent detail retrieval. Bass on the 6R is very well controlled, possibly a touch more present than on the Stax model though not by a huge amount. Both of them lack bass bloom meaning they do what the recording calls for, even when it ends up sounding less weighty than we might like. I'd say the HD800 low end comparison is also apt - but only when the Sennheiser is properly driven - being fairly similar in quantity and quality. At times the 6R seems more prominent in terms of bass attack, though other times it is right there with the Stax and Senn. I speculate this may be related to the inherent differences between full-sized electrostats and in-the-ear designs using balanced-armature drivers. The somewhat lean bass impact does take some getting used to at times - when switching from most other headphones or IEMs, these will seem overly thin at first, and over time will gradually begin to sound "right" as my brain acclimates to the lack of bass boost. I suspect there are some people who will never quite adjust to this type of sound. For them, the regular Jomo 6 is probably a better option.
Midrange on the 6R is again very similar to the 4070 - both are dry, well controlled, and very "matter of fact". The Jomo 6R lacks the stunning fluidity of a Noble K10 or Westone ES5, just as the 4070 lacks the midrange beauty of the SR-007 models... but I think that's kind of the point. There's a sense of uncolored, almost brutal accuracy that can be off putting on poor recordings yet magnificent when playing reference-caliber material. Both models are ruthlessly unforgiving, especially with vocalists. I've had several instances where the singer on a live album sounded just fine during general listening, but critical monitoring with the Jomo 6R exposed more than a few mistakes. Again, this seems to be deliberate, with the point being accuracy in monitoring rather than pure listening enjoyment.
Highs on the 6R are exceedingly neutral. There's plenty of extension without the sense of artificial sparkle added by certain IEMs. As a percussionist, my usual test material involves lots of cymbals - often times they end up sounding a bit glassy, or grainy and harsh, or muffled and dead.... there are plenty of ways to do it wrong but the 6R avoids those pitfalls. The JH13 (FreqPhase but not V2) is far more energetic and sparkly which initially sounds great but is probably more "hyper-real" than it should be. It's the equivalent of a bass boost where I might enjoy it while at the same time being cognizant that it is in fact a form of coloration. So there's no added excitement up there, but things can still get bright in a hurry if that's what's in the mix. Many albums out there have all sorts of grit and grain and the Jomo won't hide any of that - if the recording is poorly done the 6R has no qualms about showing it. 
I really have very little to complain about with regards to high frequency reproduction. If anything I'd say it still lacks the world class realism of the Stax electrostats - that again seems to be a limitation of the different formats. It's not as fast and can't maintain the decay of a big ride cymbal as well as the Stax or even the HD800. But as far as IEMs go, the Jomo 6R is right up there with the best I've heard. Again, it's somewhat hard to explain this issue but anyone who owns upper-level IEMs as well as full size cans should know what I'm talking about. It's not necessarily about preference either.... I might find the IEM presentation more appealing in some ways, while the big cans are more convincing in other aspects. Either way, it's clear they are different and difficult to directly compare.
Soundstage on the 6R is somewhat small which may come as a surprise to some readers. The HD800 has a fairly similar sound signature but manages a huge, three dimensional presentation. So what's wrong with the Jomo? Nothing really, as it falls in line with the Stax 4070 which also has a fairly compressed, "direct" sound to it. Imaging on both models is tight and focused beyond that of most competitors, but there's just not a huge sense of space involved. I suspect the "peaky" areas where the HD800 gets more exaggerated than the 4070 or 6R accounts for at least part of this difference. That, and the physically angled drivers which play some part in it. Interestingly, this intimate presentation didn't end up bothering me as much as I initially thought it would. Once I got into "monitor" mode, I stopped looking for the usual HiFi experience, and was able to enjoy the presentation for what it is. 
Worth noting: I primarily used an Effect Audio Eros 8W cable for my listening, as seen in the pictures here. The stock cable is a fairly typical CIEM cable with the traditional 2-pin connection that we used to call "Westone style" before Westone switched to something different. It comes in a gray color which is not very common - usually we get a choice of boring black or silver which will soon turn green with oxidation. As far as stock cables go, Jomo gives a fine performance, being among the more supple and sturdy stock CIEM cables I've experienced. This isn't a cable review so I won't wax poetically about the improvements caused by the Eros 8W. As usual I feel they are subtle, certainly not "night and day" as some people claim, but definitely present nonetheless. I'll just say the Effect cable upgrade gives me a more transparent experience than the stock cable alone, assuming everything else in the chain is up to par. I don't recommend cable upgrades until way down the line when you've built up the rest of your system, and I'll happily use the 6R with a stock leash under certain circumstances. Yet given the choice I prefer an upgrade like the Eros 8W if I'm doing critical listening on quality gear.

The most obvious competition for the Jomo 6R is the Ultimate Ears Reference Monitor, or UERM for short. I was so curious about it that when I saw a used pair for a good price, I snatched them up just for comparison purposes. I then had them reshelled by someone in the industry whose work I trust completely - I'm confident the result is very similar or identical to what I'd get if purchased directly from Ultimate Ears. 
I can hear why so many people enjoy the UERM. It's got a lot of the same qualities as the 6R, and generally fits the neutral description above in most ways. The difference? Jomo seems to have beaten UE at their own game. While both models have a very similar frequency response, the presentation of the 6R is superior in several ways. The main thing that gets me is the UERM feels aggressive and therefore fatiguing at times. Mid and possibly upper treble has some mild harshness to it which I don't hear on the Jomo. This was hard to nail down at first, yet fairly obvious after a few albums worth of listening. The Jomo sounds more resolving where the UERM struggles at times to hit a clean leading edge - perhaps the lower driver count has something to do with it? I'm not sure, and I don't like to perpetuate the "driver wars", but that would be one possibility.
The other key difference in on the low end, and this one took me even more time to figure out. The UERM and the 6R feel very similar in terms of bass volume relative to the rest of the spectrum. Yet somehow the Jomo has a more convincing sense of impact, despite the bass not really being any louder. After a while I discovered that although the UERM sounds pleasing on its own, in comparison to the 6R it doesn't have the tightest bass performance. Tyll Hertsens nailed it when he said (referring the the UERM): "While the bass level is good, I do find them a little loose sounding and lacking in punch." Bingo. Both models have a very similar presentation at face value but Jomo does it better if we listen closely. Again, is this the higher driver count? Maybe. Worth noting is that Ultimate Ears has a newer model called the "Remastered" Reference Monitor. I haven't heard that one so I don't know how it compares to the 6R.
Gear Matching
Lastly, let's talk equipment. I mentioned earlier that a simple iPhone or one of the better Android devices can already get excellent performance out of the Jomo 6R. I stand by that statement - I've got dozens of DACs and amps laying around here and I love nice gear as much as the next enthusiast, but I have to admit there's not a huge requirement to get high quality sound out of these CIEMs. I spent a lot of time streaming Tidal lossless on my iPad Air 2 and my Surface Pro 3. Both did a very good job driving the 6R with satisfying authority and a dead silent background. My wife's Asus Zenbook didn't sound nearly as competent due to background noise and hiss, so it's not universal, but with luck you already have at least one device in your home capable of fantastic sound with these things.
For DAPs, I had hit or miss results. My go-to is the Questyle QP1R as it usually sounds great with IEMs. It has an ultra-low output impedance and is typically very quiet. But not this time. Even on its lowest gain setting, the QP1R had the 6R hissing like an angry cobra. I've never heard an IEM do so poorly with that particular DAP, and the sonic improvement (chiefly an increased sense of resolution and micro detail) was simply not worth it compared to using an iPhone or quality Andriod device. This was a surprise that I did not see coming, so QP1R owners: consider yourself warned.

The Acoustic Research M2 did surprisingly well for having a 10 ohm output impedance. It sounded more substantial and effortless than the Questyle had. But on jazz or classical I was distracted by a weird background noise - not hiss, but rather some sort of random click-pop interference type sound. I ran in airplane mode and moved far away from any source of RF noise yet the problem persisted. Perhaps the 6R is simply too sensitive for the powerful amp section in the M2.
The original Fiio X5 had similar if slightly less annoying levels of noise, but it is clearly not in the M2's league. I found the upper midrange unrealistic and fatiguing to the point where long term listening was not desirable at all. I'd call this a textbook poor match - I believe the 2nd gen model fixes this issue, thought I don't have one here to test at the moment.
The iBasso DX90 had just the faintest bit of background grunge, low enough in volume where it didn't really bother me, and had no problems with hiss. This was a very worthwhile match for a reasonable price. The huge range of volume adjustment is appreciated for dialing in exact levels, and the generally neutral tone made it easy to separate good recordings from bad. In the end this is one DAP which is worth using over an already excellent sounding iDevice or Android, for those looking to move up the chain without spending a fortune.
Sometimes you want a more musical approach. The Pono was virtually silent and made a great pairing, its somewhat musical presentation taking a bit of the edge off the 6R's serious character. I also enjoyed Sony's punchy, smooth ZX2, despite the relatively loud hiss it exhibited. It sounds counter-productive but again the pairing of musicality from the DAP and accuracy from the 6R just worked on some level. Same for the Calyx M which had practically zero hiss and gave the 6R a superb low end kick. If only it had a better battery. 

HiFiMAN's HM-802 and HM-901S siblings were interesting. The 6R really showed off the value of having a modular amp system. The "standard" amp which shipped in the 802 was a little hissy and a lot uninspiring. Not terrible but definitely not impressive either. Switching to the Minibox Gold amp card which came in the 901S gave excellent results but the hiss was again too much for me - others might find it within acceptable range but I'm more sensitive than most. The 802 plus Minibox was very similar to the Sony ZX2, while the 901S plus Minibox was like an improved Pono experience, though with more hiss. Ultimately my favorite amp card was - surprise - the IEM card. It was nearly silent and had excellent detail retrieval, along with just the right amount of gain. The 901S gave spectacular "monitor" results while the 802 played it warmer and more casual. I enjoyed the 901S more but the 802 definitely has its place. 

As much as I liked the various DAPs, my favorite results came from listening at home on a bigger setup. Again, there aren't a huge number of desktop amps or DAC/amps that pair well with the sensitive Jomo. Beasts like the Violectric V281 and Simaudio 430HAD, normally very quiet with any headphone you throw at them, both had an excess of undesirable noise. The Pass Labs HPA-1 even more so. The Cayin iHA-6 in balanced mode was workable, especially when fed a lower voltage signal to keep levels manageable - a standard 2V signal meant precious little room for dialing in proper volume. 
A very music combo I found was my Expo 93 (Examplar modded Oppo unit) feeding a NuForce HA-200 amp via analog outs - no external DAC in the chain. This is a sweet, musical pairing which renders female voices and stringed instruments with a certain magic that is just the ticket for relaxed listening. I wouldn't use this setup for critical monitoring, as it is merely good and not great in that aspect. For late night listening after a long day or work, perhaps with a nice adult beverage in hand, this is a compelling setup. The Jomo 6R is a chameleon which lets the rest of the chain shine through clearly.
Expo 93
In the end I went back to where I often go with CIEMs - the Anedio D2 and the Questyle CMA800i DAC/amp units. Both have stunning headphone outputs with inky black backgrounds. I've been messing with adding JPLAY to Foobar on my Surface Pro 3 - it really does make a worthwhile difference without changing the interface I'm so accustomed to. JPLAY cleverly installs as an ASIO driver which can then be selected as an output device inside of Foobar. It takes a resolving transducer to showcase the full extent of improvement, and the 6R is up to the task. The CMA800i seemed better initially, until I recalled that the Anedio seems to scale well with USB to SPDIF conversion. So I threw in the new Singxer SU-1 which is at present the bang-for-buck champion of the world as far as I'm concerned. Now the Anedio kept pace and even surpassed the more expensive Questyle in some areas. The combo of JPLAY, Singxer, Anedio, and Jomo 6R is startlingly resolving, and I admit to losing more than one evening meandering through my favorite recordings. The whole system is under $5k (the number I hear thrown around a lot to indicate "affordable" systems) including a top-model Surface Pro 3, power conditioner, nice cables, etc... I've heard waaaay more expensive rigs not live up to the same standard. Excellent recordings on this rig will knock your socks off and poor recordings, well, you probably won't last very long on those tracks before skipping to something else. Which is the same way I describe my Stax rig when using the SR-4070.
DSCF2998.jpg Singxer SU-8 USB Bridge

If DACs with four-figure price tags aren't your thing, the Grace Designs m9XX is a worthy option. It gives just the slightest amount of hiss, not enough to bother me (and as I said, I'm more sensitive than most in this aspect). The big volume knob is excellent for dialing in perfect volume levels, and the Grace has just the right mix of detail and musicality to make the 6R shine. It doesn't keep up with the Anedio and Questyle units, and for $499 I wouldn't expect it to. 

The Jomo 6R is certainly the most neutral IEM I've heard. Which can be a very good thing if one is honest about what they really want. Many claim to want neutrality when in reality I suspect they prefer some minor coloration - a bit of warmth down low, perhaps some midrange bloom, maybe a touch of smoothness in the upper mids and highs. And there's nothing wrong with that. There are many other "mostly neutral" IEMs that I can heartily recommend: the Noble Savant SLA, Unique Melody Miracle, and Lear LCM-5 all come to mind. The first step is figuring out what you're really looking for, and proceeding from there. 
For someone sure they want brutally, beautifully neutral sound from a custom IEM, the Jomo 6R is an excellent choice. It handily beats the original Ultimate Ears Reference Monitor by doing the same things but doing them better. It's really quite easy to drive and sounds very respectable from everyday gear like an iPhone, making the 6R very accessible compared to some CIEMs which are more source-demanding. At the same time it does reward quality gear, being among the most revealing ways to listen to differences between DACs or transports. Ultimately the 6R is a unique and very appealing choice which I can easily recommend.

I think you made that pretty clear! 
Superb in depth review. 
You have a way with words my friend. Thanks for sharing your thoughts.