Saturday 29 January 2022

REVIEW & MEASUREMENTS: Chord Mojo DAC/Headphone Amp. A note on LH Labs (Light Harmonic "subsidiary") audio crowdfunding. And Neil Young's ultimatum to Spotify. [Early Mojo 2 specs.]

Mojo as shown here in the official rubber and leather Mojo Case. Looks and feels great in the hand. Shown with AKG K371 headphone.

Well, in the "better late than never" category, when I returned my friend AudioPhil's Cayin RU6 the other week, I borrow his Chord Mojo ("Mobile Joy", ~US$475 new but I think currently discontinued) for a spin!

This DAC has been out since October 2015! That's ages ago in the world of electronics. However, to be honest, high fidelity audio reproduction is rather ageless whether the device is 10 months old or 10 years old. So long as the internal components aren't deteriorating with age ("break-down" instead of "break-in", right?).

As you've probably seen in countless reviews on the Mojo (like here, here, here), this seems to be quite a popular DAC with a good following. It has been said that Chord sold something like 100,000 of these over the years. Objectively, the Stereophile review in fact showing some impressive performance results back in 2016.

As usual, Chord gear tends toward the large bulbous glowing buttons, at times steampunk metal esthetic. Colors are used to provide feedback on volume (the pair of buttons for +/- volume) and the main power button (red in image above) which changes color for sampling rate. I think this is an acquired taste and figuring out the colors will take some time as you get used to the sequence of colors in a rainbow with red (lowest volume/samplerate) on one end and purplish/grey/white (highest) on the other..

Above, we see the Mojo out of the case. It's a compact chunk of CNC milled aluminum with official dimensions 8.2cm x 6cm x 2.2cm, 180gm/0.4lbs. As you can see with the glowing lights while unconnected, it's obviously a self-powered unit with a battery inside. This does make it larger and heavier than a simple USB DAC dongle.

To the right of the unit, we see the digital I/O with micro-USB (up to 768kHz and DSD256 DoP input), and both TosLink (to 192kHz) and Coaxial (to DSD128 DoP and 768kHz!) S/PDIF inputs. There's also the power USB connector for charging the battery - blue indicator tells us it's "75-100%" charged; as usual, consult the manual for what colors mean.

There's no special digital input selection mechanism. If multiple digital sources are plugged in, the priority goes USB > Coax > TosLink.

And on the left, we have the dual 3.5mm stereo headphone jacks:

Not sure if that QR code and number is a serial number or not - blurred to protect the innocent.

The dual headphone outputs play simultaneously and are rated for 8-600Ω impedance headphones with spec'ed output impedance at 0.075Ω. Since there is a single volume control, how loud the headphones play will be dependent on relative sensitivity. This is certainly a convenient way to share the output; probably good to use the same or similar types of headphones for both outputs just in case one is much louder than the other.

From the top, we can see the round push buttons (they're actually spheres that will roll under your fingers) including the +/- volume control and power button.

At first I was a little surprised to see the amount of Chinese on the label for a "Made In England" product! This is legit and has been the labeling style since 2019 at least; AudioPhil tells me that this unit was purchased in 2019.

Otherwise, there's no other special features or settings except for a 2-level LED brightness control (turn on and then briefly tap on both volume buttons to toggle) and the "Line Level" mode (turn on the unit while holding both volume buttons).

When "Line Level" output is set, both volume buttons will turn purplish color. All this does is set the output to 3.10Vrms which is higher than the usual 2Vrms line level we see with most RCA single-ended outputs. You can still use the volume buttons to deviate from 3.1V.

Pretty cool that Chord makes the Poly addon for wireless access and local SD-Card playback although reviews of usability don't seem that great.

Alright then folks, let's have a look at the audio output characteristics and quality...

I. Oscilloscope, Impulse Response, Digital Filter, Output Impedance, Headphone Output Power

Starting "microscopically", we can have a peek at the sine and square waveforms coming out of this DAC. Already, right from the start we're seeing some very clean looking signals:

We can see that right-left balance is excellent. There's no temporal shift between the channels. For the bandlimited square, we can see the slight but symmetrical over/undershoot at the edge transitions. This is a tell-tale sign that we're looking at a linear phase filter with both pre- and post-ringing if we have a peek at an impulse from the digital filter.

And here's the impulse response:

As you can see, this is the 26,368 taps "WTA" (Watts Transient Aligned) filter. Basically a very high order linear phase setting (we've discussed filter types here). Assuming the mathematical precision is high, this should result in an extremely clean DFC (Digital Filter Composite) graph which I've been showing for years:

There is really only one word to describe this: textbook. This is what basically an ideal "brick wall" filter would look like in the frequency domain. Notice the very low intermodulation and harmonic distortions from the 19 & 20kHz sine signal. Very nice! This should presage some excellent results on our resolution tests coming up. (If you want to achieve a similar DFC graph, check out the Raspberry Pi 3B+ article with "Extremus" settings in piCorePlayer, or HQPlayer "sinc-M".)

Let's zoom into the edge of that white noise signal where the filter transition band occurs in the analogue output:

Yeah, it's sharp! We're looking at >100dB of suppression in the span of <500Hz with a flat frequency response almost out to 22kHz. As I said - brick wall, baby!

And as a headphone amp, here's the output impedance plotted across the audible frequencies with 7 readings from 20Hz to 20kHz:

Very nice again. The official specs say 0.075Ω. While I can't measure with the precision down that low using the 20Ω load and my meter, I can certainly confirm that it's <0.2Ω for much of the audio spectrum. Notice though that particularly from 5kHz onwards, it climbs up to about 1Ω by 20kHz. Not an issue, but this means that with lower impedance headphone loads, there's likely going to be some upper treble attenuation.

Indeed we can see some roll-off with both resistive as well as the more complex Polk Ultrafit 2000 headphone loads (96kHz sweep). Take note that the Y-axis is very small and I'm blowing the picture up here. The top is only +0.5dB, lower edge -1dB. As expected, with the low output impedance, variation in the electrical frequency response is very small until above 5kHz where there's more of an upper frequency attenuation affecting the lower impedance 20Ω load and Polk headphones (see Polk Ultrafit 2000 impedance graph here) most. That rising output impedance as shown above might be part of the reason.

Since this DAC/amp has a battery inside, it can produce a bit more power than the usual USB dongle DAC connected to a smartphone. Measured maximum power available is 43mW (max 4.9Vrms) into 560Ω, 250mW (max 4.37Vrms) into 75Ω, and 590mW (max 3.44Vrms) into 20Ω. Official tech specs say 35mW into 600Ω, and 720mW into 8Ω so my measurements jive with these numbers.

II. RightMark PCM

Time now to take a look at the resolution of this device with some comparisons as per usual procedure.

Starting with "standard" CD resolution, let's compare this with the Cayin RU6 we looked at last week, and a few others. Let's set the output volume to around 2Vrms like typical desktop DAC such as the Topping D10s we're also comparing. Due to the volume levels, the closest voltage is 1.95Vrms for a 0dBFS pure tone sine wave.

Note: for the Topping D10s and D10 Balanced, I'm using a linear phase filter firmware these days which cleans up the frequency response.

Clearly, the outlier among these devices is the Cayin RU6 R-2R mobile DAC/amp. Otherwise, the Mojo and others (LH Labs Geek Out V2, Topping D10s, Topping D10 Balanced) simply performed quite well as accurate 16/44.1 DACs with little variation among them. Note that the stereo crosstalk does vary based on the cables used (for example, I used a 3.5mm phono-to-RCA for the Mojo). I wouldn't worry about the absolute value of crosstalk unless very poor like <60dB across the audible frequencies which practically is still audibly excellent even if low for modern digital devices. Remember that even high-end phono cartridges are only capable of around 30-40dB if you're lucky!

Going hi-res now...

As you can see, we have quite a few numbers here. Notice that I've included the TosLink input as well showing identical performance to USB. This should of course be no surprise for audiophiles these days - yes, "Bits Are Bits" when it comes to high quality digital devices. My feeling is that if indeed you hear significantly different results (assuming volume controlled and no intervening digital processing) from a USB vs. Coaxial vs. TosLink input, then there's something not right with the DAC or maybe errors are being introduced somewhere. Even though jitter might be different between digital interfaces, it would also be highly abnormal to be able to hear jitter variation!

To keep the graphs simple, let's just plot out a few of these results to prevent too much clutter:

As you can see, the Chord Mojo performs very well, almost at the level of the modern Topping D10s/B. We can see the benefits here of the Topping D10B's balanced outputs with lower noise, better crosstalk, and lower distortion.

There is one other graph worth showing:

That's of course the difference between USB and TosLink, galvanic isolation achieved with the TosLink optical. The playback was with my Raspberry Pi 4 "Touch" streaming device for USB and I used my old Squeezebox Touch's TosLink out (connected to server over WiFi).

Let me contextualize the environment. The test bench is quite bright with 4 CFL bulbs overhead. There's a fridge about 6' away from the Mojo. The i5 NUC computer is about 4' away. All this is plugged into the same power outlet with the Pi 4 using an inexpensive switching power supply. No effort has been made with special power cable, no power conditioner (generic "surge suppressor" power bars used). All this, and as you can see, the noise floor is low up to 48kHz. Even with the USB input, we're looking at -126dB 60Hz hum. Obviously I'm not saying one cannot or should not spend money on fancy power conditioner, power cables, or even a better power supply. Just be mindful when people say all kinds of things about "even quieter background noise" or "black background" - love the hilarious discussion here.

For completeness, for the handful of you who still cares about 192kHz: ;-)

In light of the 24/96 results, nothing is really added by the 192kHz data other than the observation that frequency response doesn't extend beyond what we saw with 96kHz.

Overall, the Chord Mojo functions very well as a PCM DAC with excellent, accurate, high-resolution performance.

III. RightMark DSD & Ultrasonic Noise

Let's now have a peek at DSD playback. We'll use the SoX-DSD conversion of a high resolution 24/96 RightMark test signal and see how well the playback measures (as discussed here).

When playing DSD, there's a -6dB attenuation to the output level so I increased the volume to compensate, back to 1.95Vrms as per the PCM measurements:

That looks great. We basically achieve the same level of performance between DSD and PCM. As expected, increased ultrasonic noise with DSD64.

Quick peek at the DSD noise level with a 1kHz 0dBFS signal up to 192kHz bandwidth:

We see the typical ultrasonic noise patterns using the sdm-8 setting in SoX-DSD. Also our first look at a 1kHz THD+N of about -109dB which is very good.

[On a side note, supposedly the Hugo 2 and I assume other higher-end models have a "DSD filter" to remove the ultrasonic noise.]

IV. 1kHz THD+N

Alright then, let's have a peek at the THD+N with 24/96 PCM playback:

Excellent result of around -111.5dB (0.00027%) for both channels. Notice on this unit the right channel has a bit of noise at the base of the 1kHz tone. It's way down at -140dB so no worries about this being audible. I wonder if this is present on other units.

Let's run a stepped sine measurement to check out distortion across output levels leading up to 4.9V (+16dBu). Beyond this voltage into a high impedance load (like 600Ω headphones), the signal will visibly clip:

The 3rd harmonic predominates until by about -10dBu, then the 2nd overtakes. I've put the cursor at +2.2dBu (1Vrms) for reference which are the dBr numbers in the legend.

Using that Generator Level Sweep, we can look at linearity of  the output level:

Looks good with +/-0.1dB point at -110dB from unclipped 4.93Vrms single-ended upper level.

V. Multitone

Beyond single-tone THD-type FFTs, let's have a look at some multitone signals. Here's my Triple Tone TD+N measure (as discussed here):

A TD+N of -104.5dB is excellent with harmonics and intermodulation products below -110dB. Clearly, a very clean signal (especially compared to the Cayin RU6 last week!).

As for the 1/10 Decade Multitone 32, again with output level set at 1.95V with a 0dBFS pure tone:

100+dB distortion-free range is excellent. Notice that the highest distortion peak here is the 60Hz hum which may not be present if you're running purely off a battery such as when listening through a smartphone or even with TosLink galvanic isolation as shown above.

VI. Jitter

Let's look at the perennial digital "audiophile boogeyman", jitter. Here are the 16-bit and 24-bit J-Tests with the USB input:

That's beautiful.

What about the S/PDIF inputs especially TosLink which tends to be the most jittery interface for many devices:

Wow. Very nice. This is again really clean and Chord is doing a phenomenal job with jitter-reduction. I did not test the S/PDIF Coaxial input, but have no reason to think it would not perform well.

VII. Subjective & AMPT Recordings

As usual, I had a listen for a couple of hours before measurements and then afterwards to correlate the subjective and objective impressions.

Like with the Cayin RU6 review, I used a combination of the 1MORE Quad Driver IEM, the Drop + HifiMan HE-4XX, and Sennheiser HD800 mostly. This device, capable of higher voltage levels, was easily able to drive demanding headphones like my modded Dekoni Blue beyond the limits of dongle DACs like the Cayin.

With Meat Loaf's passing recently, I had a listen to Bat Out Of Hell II: Back Into Hell (1993, DR11) the other day with this DAC/amp. You know, it's such a pleasure to listen to a well recorded/produced rock album with good dynamic range. Like them or not, Meat Loaf and his longtime collaborator Jim Steinman (died April 2021) have produced some really sweeping, dramatic and fun tunes. Pump up the volume and just be immersed in the energy of the music! The complex "Out of the Frying Pan (and Into the Fire)" is a great one to just experience the ability of a DAC like this to convey bass extension yet resolve the individual instruments in the mix. Slower tracks like "Objects in the Rear View Mirror May Appear Closer Than They Are" and "Lost Boys and Golden Girls" allow us to appreciate the lyrics, enunciation and "prosody" (maybe there's a better word) in the delivery. The Chord Mojo delivers the goods. ;-)

Flipping between headphones and listening for differences in tonality is very convenient thanks to the dual outputs. The relative "airiness"/"space" of the Sennheiser HD800 compared to my other headphones was obvious when doing these A/B comparisons for example. Remember that since there's only 1 volume control, be mindful of relative headphone sensitivities.

Recently I've been listening to Dave Gahan & The Soulsavers' album Imposter (2021, DR9). Gahan as you probably are aware is the front man for Depeche Mode. This is an album of covers done in a rock style (as opposed to the DM synthpop). Not the best recording/mastering with a bit too much reverb applied for my taste. Nice covers of "The Dark End of the Street" (I think The Commitments version is still my favourite) with lots of moody atmosphere. The stripped down, melancholic, "Always On My Mind" with acoustic piano, echoey vocals, and overlaid background female singers, plus electric guitar sounded great through the Sennheiser HD800 with the music seeming to emanate at least a bit "outside" of the head. For this track, Gahan summons his inner Elvis, rather than his disco-pop Pet Shop Boys.

I listened to the SACD/DSD64 rip of Friday Night in San Francisco (1997 Sony SACD release, DR14) through this DAC for a taste of some DSD. All those insanely fast guitar plucks are there for the audiophile to enjoy on "Mediterranean Sundance/Rio Ancho". Great tonality on the instruments, each with a nice harmonic signature, tight transient "attacks" on those strings. As a live recording, we hear the audience chiming in once awhile; plenty of detail and nuances throughout. Separation of DiMeola, McLaughlin, and deLucia's parts well demarcated; no problem for a hi-res DAC like this to tease apart the individual guitars.

As I've been doing since last year, here's the AMPT with the Chord Mojo connected to my RME ADI-2 Pro FS and recording the 16/44.1 test material as 24/96:

Sound-wise, I would say that this is an "accurate", "transparent" sounding device. I don't hear anything "romantic" in this sound like extra "warmth" or anything like that. This is simply "high fidelity" playback.

VIII. Conclusions

Dual purple volume buttons = "Line Level Mode", 3.1Vrms output with 0dBFS signal. Red power button = 44.1kHz.

Have a look at Chord's well-done video if you're curious about how the company describes its DAC technology. If we cut through all the fancy talk about its FPGA and "Pulse Array" terminology, what we basically have here is a custom high-performance, multi-level ("4-element") sigma-delta design with a strong digital interpolation filter. The Xilinx Artix-7 FPGA performs the touted (excellent if not already "over-engineered") 26,368 taps "WTA" interpolation up to 16fs (presumably 705.6 or 768kHz depending on sample rate) and then further interpolation takes this to the multi-bit 2048fs (~100MHz). I've read online that the Mojo's modulator uses a 5th order noise shaper so we might be able to see rising noise floor from this.

Let's have a peek using the E1DA Cosmos ADC with its flat noise floor out to 192kHz (384kHz sampling rate) - here's a 0dBFS 24/96 PCM 1kHz tone, set to 3.10Vrms "Line Level" out:

Compare this to the old LH Labs Geek Out V2 based on the ESS Tech ES9018AQ2M chip:

As you can see, while the LH Labs Geek Out V2 has a higher noise floor and the THD is not as low, the noise floor is flatter than the Mojo which rises above 100kHz (the Stereophile measurements from 2016 hints at this). If we compare this with the wideband DSD noise graph in Section III, it looks similar to the SoX-DSD256 sdm-8 setting. Presumably with higher order noise shaping and other modifications in the upper model Chord DACs, this rise in the noise floor will be pushed further out in frequency and/or attenuated. There's no need to make a big deal out of this since it is high ultrasonic and no speakers/headphones will be able to reproduce this stuff; worth noting from a technical/academic perspective.

With the Mojo result above at 3.1Vrms and THD -118.7dB (0.00012%), this is even better than Chord's official spec of  "THD @ 3v: 0.00017%". I saw that Audio Science Review measured the Mojo back in 2018 and found a range between SINAD 99-105dB at 2.17Vrms. I'm seeing a significantly better result with this unit at -111.5dB THD+N, 1.95Vrms as shown above (Part IV), improved to -114dB at 3.1V (no degradation with increased output). I did not see the variability reported by ASR either.  As such, I think ASR under-reported the resolution of this device. I would put this DAC higher in the SINAD "rankings" (to be clear, this is just a rough comparison) and closer to something like the Benchmark DAC3. Who knows if age, variability between units, or board revisions may play a role.

The Mojo is an example of a technically competent DAC/headphone amp with excellent digital filtering, low noise, low non-linear distortions, low jitter, and likely able to provide enough power for your headphones with very low output impedance.

I would argue that the Chord sounds excellent simply because it's a well-engineered type of sigma delta DAC, with clean analogue output stage and headphone amp that performs well on objective measurements. "Subjectivist" audiophiles should take note that maybe measurements do correlate to sound quality assuming they like the sound of Chord DACs in general.

Every company will tout their own special features, and in this case it's about the "number of taps" (up to 1M with the Hugo M-Scaler) and how many "elements" (up to 20 with the Chord DAVE) of their "Pulse Array". Of course, big numbers will help feed the advertising of products but let's be honest as well about whether these metrics really will make a difference once crossed thresholds of diminishing returns. Where's the evidence that these huge "taps" will actually improve anything of significance in the "time domain" as claimed (and as parroted by unbelievable ad-men like this too afraid to be told he's wrong in the comments), for example?

As a "wish list", here are a few things I think are worth updating or changing if we were to redesign this device for the 2020's:

1. USB-C interface should be a given at this point in history. USB-C would be more robust than the micro-USB. I've heard of folks complaining that the connection can be a bit loose or disconnect with movement - not a good thing for a mobile device! Also, with improved FPGA tech and battery system, I would imagine cooler running and battery life to be extended (>15 hours on a charge would be convenient). Other upgrades like fast charging, and wireless Bluetooth (AAC, aptX, and LDAC codecs please) would be beneficial, maybe incorporating other features of the Poly.

2. I'm still not a fan of the color status indicators. Yeah, the organic-looking bulbous glowing marbles can look cute, but there is a bit of "form-over-function" here. The main issue is that I like knowing exactly what my volume settings are. For example, the Cayin RU6 tells me if I'm exactly at 75% volume whereas these shades of colors lack clarity. Imagine if we have very sensitive headphones. Wouldn't it be much easier to tell my buddy: "Hey man, don't go above 35% volume on the Mojo if you care about your hearing!" instead of "Hey man, don't go above light cyan on the Mojo cuz you'll go deaf!"

Also bad if one is color-blind! ;-(

3. For a unit of this size which is not particularly small/thin/light, a user-replaceable battery would be preferred. When new, battery life on a full 4+-hour charge is maybe around 8-9 hours reported by users depending on how much power your headphones need. Over time the battery life will slowly diminish so it would be nice for the user to easily replace this without fiddling with a bunch of hex screws. (As it is, it doesn't look too difficult and batteries can be found on eBay - here's a video on how to open it up and replace the 7.4V 1.65Ah LiPO4 'ARL9056' battery.)

4. It would be nice to be able to run this DAC in "desktop mode" without engaging the batteries. Currently one could run this with USB power plugged in indefinitely (I've heard that it turns itself off after 12 hours, I didn't check). The problem is that the unit will run quite warm, and could further wear out the batteries. (Here's a conversion video that just disconnects the battery inside - clearly inelegant.)

5. More power would be nice: 1W into 32Ω would be a round number to aim for I think. A high/low gain setting would be very good for gross control over whether one is pairing with low/high sensitivity headphones. Also, I like the current 2 headphone outputs - however, at this price point, let's see a standard 3.5mm headphone jack and a balanced 4.4mm Pentaconn like the Cayin RU6.

6. The digital filter performs beautifully already. As suggested above, I don't know of any actual research on digital filters showing the need for super-high tap lengths other than Rob Watts and his claims for mega-tap filtering (or PBBG).

I would love to see a volume-controlled blind listening test showing humans are able to differentiate a steep but relatively "small" 1,000-taps vs. 1,000,000-taps linear sinc filter assuming similar cut-off say from 21.5kHz for 44.1kHz material upsampled to 768kHz. If truly this made a difference, it should be quite simple to show with a few trained test subjects given the 1000x difference! I wouldn't hold my breath for any such results.

Personally, if it's a compromise between battery life vs. huge filter processing, battery life would easily win.

May I make a suggestion since the digital filter is a focus for Chord? How about implementing an Intermediate Phase Filter option with all those thousands of taps for times when we're listening to modern compressed rock/pop/electronica? This will reduce potential pre-ringing with minimum change in group delay - life is full of compromises, right? (Or do we audiophiles just not listen to that type of music?! ;-)

7. While I have no concerns about the sound quality, I suppose updating the product to a higher "element" design would further lower the noise floor especially for balanced output. To save cost and differentiate the less expensive Mojo from other Chord DACs, I suspect a modest increase in the "Pulse Array" (maybe "6-elements"?), combined with higher order noise shaping (like 8th-order, the DAVE is reportedly at a remarkably high 17th order!) should do the job. A consumer mobile device obviously needs to find balance between battery life vs. performance vs. price.

As I have discussed over time, I believe we've reached a level of maturity with DACs these days such that "perceptibly perfect" devices are easily accessible. As such, even with increased numbers of "elements" and even higher tap-counts I doubt will have much effect (I know, Chord and Rob Watts believe differently) - this is part of the "diminishing returns" discussion. As we talked about last week, for some audiophiles, I think it's more about "intentional imperfections" leading to subjective euphonic benefits than yet more inaudible technical precision/resolution.

I believe the Chord Mojo 2 might be announced imminently. It'll be interesting to see what this new model brings to the table and it'll be fun to compare with my wish list above. ;-) Given the performance of the Mojo 1 here, if the Mojo 2 looks good, I might even buy one for office listening!

I gotta say, AudioPhil has quite the "tale of two DAC/Heaphone Amps" in his possession between this Chord Mojo and the Cayin RU6 I wrote about last week! The devices are examples on both sides of the spectrum with an "accurate" Chord DAC aimed at transparency and the Cayin R-2R that has "subjective character" with potential euphonia. I guess depending on the mood, what music one is listening to, and headphones used, AudioPhil will have the opportunity to experience both sides of the coin. Choice is never really a bad thing! Thanks man for letting me borrow this DAC/Amp for a spin.


You might be wondering why I picked out the old LH Labs Geek Out V2 DAC as a comparison device for these last couple of posts. Well, it's also a USB-dongle headphone DAC, and the MSRP when new (~US$250) was about the same as the Cayin last week. Also, this allows us to be reminded about the idea of crowdfunding and audio!

The other day I was reminded of the company while reading through this unfortunate "Light Harmonic (LH Labs). Scam? USD$6 million not delivered since 2014" forum thread. I can reminisce of a time just before 2015 when crowdfunding was seen by some in the audiophile press as a possible "future" for the audio industry. Larry Ho and Gavin Fish back in the day being mouthpieces of this movement - "How Indegogo Will Help Save an Old Dying Industry". Not only Stereophile, but guys from The Absolute Sound also perpetuated the news around the hype.

Evidently, this salvation for an "old dying industry" was not to be. As you can see in the long-running forum thread started in 2017, it looks like folks have been awaiting delivery on a number of "paid" items from LH Labs. At this point, chances are slim that there will be any kind of product to show for the money spent by many unfortunate customers. I think from the start, many had questions about whether this kind of funding model would work for a majority of projects. In reviewing my preview to the Geek Out V2 back in 2015, I think I showed appropriate skepticism. Human psychology being what it is, unless you're dealing with really good people completely up front whether the venture leads to success or failure, the bias does tend to be for behaviours that favour greed and an attempt at ego preservation.

While I don't think failure/success rates have been fully published, estimates are that for Indegogo, success rate is "between 17-18%". With those kinds of odds, obviously if you're a prospective buyer, make sure to be mindful of the reputation of the folks making the sales pitch and that you're willing to part with whatever dollars you'll send their way. It's one thing to send a few bucks for a unique product, but once it gets into 3 or 4 (or 5!?) figures, better make sure to do your due diligence! I'm curious, in the years since, have we seen Stereophile or TAS write anything to follow-up on the crowdfunding movement or ever warned consumers about this kind of business model? If not, why not? As usual, it's worth wondering if the "mainstream" audiophile media holds much allegiance to consumer interests as opposed to those of the Industry.

If we look at the Indegogo page on products like the LH Labs Geek Pulse and Geek Wave, we see that the company has sent out updates here and there over the years, apparently stringing along the idea that work is being done (for example, for the Geek Wave, they posted a few pictures up to Jan 2, 2021). Then there are the thousands of comments by folks who feel "ripped off".

Clearly, Larry Ho and Gavin Fish were not exactly the most reputable of folks to be entrusted with millions of dollars; who knows where the dollars went. Funny reading this article about Ho on "serial" entrepreneurship from 2015 in an Asian news site. Sure, taking risks and promising all kinds of things will capture "venture" dollars a lot of the time... until it doesn't, and shaky schemes collapse.

Inexplicably, Larry Ho has become Lawrence Hope these days (as in "I Hope karma isn't too hard on me."), and Gavin Fish turned into some kind of true crime warrior! I dunno, maybe it's some kind of subconscious desire for absolution for sins of the past. You can't make this stuff up, folks!

By the way, the only other product I purchased which came from crowdfunding was the PonoPlayer. At least with that, which originated from Kickstarter, I respect Neil Young and Ayre for getting the job done and delivering. Of course, I didn't think Young's silly promotion of hi-res audio realistically helped; but that's another story.

As usual, when we see an audiophile press that's mostly interested in making sales for the Industry (instead of promoting consumer interests), and questions of "snake oil" around claims from the "High End" particularly, make sure to be wise about spending money on a lot of this stuff.

[Addendum: A terrible article in support of the LH Labs scam model by Lee Scoggins (circa 2014), currently the CEO of the publisher for TAS and Hi-Fi+ as shared on AS.]


In news this week, fascinating what happened to Neil Young in his little spat with Joe Rogan over COVID-19 ending up in Young's music being pulled from Spotify. No need at this point IMO to get into the rights and wrongs of the pandemic, I think too much has already been said in that regard. I think it should be no surprise that this was the outcome for Young's ultimatum. I respect Young's character in standing up for his principles and I see the WHO Chief thanking him. But I think if Young wanted to make a meaningful statement, isn't it a little late given where we're at in the pandemic? Rogan caught COVID in early September 2021 and has already expressed his views for months. Looks like the horse has been "out of the Barn" for awhile already. ;-)

Speaking of Neil Young's activism and posturing, remember back in 2015 Neil Young also removed his music from Spotify? Back in those days it was because of the need for better sound quality. Seriously guys, of all the music and genres, Young's discography does not need hi-res - CD 16/44.1 is more than enough for this stuff IMO. He said back then "When the quality is back, I’ll give it another look. Never say never." He even said: "I don't need my music to be devalued by the worst quality in the history of broadcasting or any other form of distribution. I don't feel right allowing this to be sold to my fans. It's bad for my music" on Facebook. Well, even though Spotify never improved its sound quality, Young's music eventually went back on the system by November 2016. And now look at this: Neil Young returns to SiriusXM after pulling music from Spotify. LOL - SiriusXM has some of the worst broadcast sound quality I've ever heard with obvious data compression distortions and EQ (music channels get about 40-64kbps over the air)! Oh well, to be Young and idealistic. ;-)

Look ladies and gents... Like with everything else on the Internet, there's so much misinformation, disinformation, and irrational content that it's simply impossible to "sanitize" and "protect" the presumably innocent, unsuspecting public at this point in history.

Potential for chaos is the price of free speech and obviously every society, community, person will need to find a threshold of what is acceptable. Sometimes the fantasies we find online are relatively harmless; the fantasies in "High End" audio are mostly entertaining. Other times, the fictitious nonsense will cause major troubles. The virulence of COVID-19 obviously has had a huge part to play in creating disharmony in society since each of us will have a different level of tolerance for the risk it poses for ourselves and those around. And so the outcomes for each society and relative emphasis the culture places on "safety" and at what costs through the phases of this pandemic are probably predictable in retrospect to a certain extent. Fascinating how various countries have dealt with the challenges and the kinds of resistance citizens have engaged in.

There will be time enough in the years and decades ahead as we get past this phase in our history for everyone from common folks to academics to study the medical epidemiology, individual psychology, collective behaviour/sociology, media coverage, economics and politics of this pandemic. I would not be surprised if we start seeing a bunch of books by the end of the year retrospectively reviewing "What just happened?".

Regardless of all the "Information Wars" online, at least in the Western World, I think the underlying solution IMO is still better education. Teaching ourselves, those around us, and the next generations to be better critical thinkers is perhaps the most important job that the educational system, news media, and leaders in all kinds of areas must try to do. Information is cheap, but the skills to be able to extract truth, and the wisdom to develop understanding I think is what's "priceless".

As for censorship, whether it's the idea of banning podcasts, blogs, videos, articles, etc. that some are calling for, society will always have "fringe groups" of one sort or another which someone, somewhere will want to suppress. How we set the thresholds of what is "acceptable", what should be outlawed, which are "depraved", and which are sadly a product of mental illness (even perhaps to be pitied) will simply reflect societal norms and values. As I quoted from Carl Jung on the article about audiophile psychology recently, "The pendulum of the mind alternates between sense and nonsense, not between right and wrong." Let's see how societies around the world find "sense" rather than some kind of idealistic morality as we hopefully reach the conclusion of these pandemic perturbations through 2022.

Well, locally here in the Vancouver area, the rate of new Omicron infections has passed a peak, hospital numbers are still high but likely in the midst of dropping, strain on health care resources calming, and death rate should be turning down soon. I think humanity has been on the whole fortunate to have this wave be the relatively lower virulence Omicron strain. I think we can be optimistic for the Spring and Summer 2022.

Through all this, I hope you're staying healthy and enjoying the music, audiophile friends!


Addendum: January 30, 2022

As per Verifonix's comment below, it looks like Hefty_Miner posted some preliminary information on the Mojo 2. Let's take a peek at the list with my own comments in regular italics:

Chord Electronics
Black Finish Only
Price: £ 449 (UK)
= ~US$600 direct conversion
About 7 years after Chord Electronics created the portable headphone / DAC amplifier "Mojo", the new "Mojo 2" is released. 
UHD DSP - interesting use of the term "UHD" as if channeling the video world
・ Advanced DSP allows integrated tone adjustment over all frequency bands
・ UHD DSP technology operates at 705 / 768KHz
・ Uses 104bit and extended internal noise modulation
・ UHD DSP provides bass and medium The entire frequency band can be adjusted in 18 steps for each frequency band of bass, bass, and treble.
     - Using a powerful DSP to operate at 700+kHz and high bitdepth, cool

-The volume adjustment range has also been improved from + 18dB to -108dB. It has two types of operating ranges, low volume and high volume. - okay looks like we have hi/lo gain
・ It is equipped with a new cross-feed mode with 4 settings controlled by DSP, realizing a space effect for listening like a headphone speaker. - more DSP features. Hope it sounds good!
・ Introduced a menu system - wondering how this works? display screen? app-based?
Equipped with a mute function, 4-step customization function, travel button lock function, tone control function, etc. 
・ Digital input
USB-C input has been newly installed to increase the number to 4 systems, enabling more flexible support. - good, USB-C nice.
USB-C, optical, coaxial (including dual data for M scaler), and Micro USB installed.
3.5mm mini jack headphone output There are two systems, and up to two people can listen to music at the same time. - I've listened to the M scaler demo a couple times now and it doesn't blow me away for the expense. Could care less... What's the point with a mobile DAC like this!? 
- still dual 3.5mm single-ended is a bit of a let-down since balanced output would do more for resolution than basically anything else here. A comment in the link above listed 600mW into 30Ω - basically little increase in output power.

-Charging system
New FPGA-based charging system greatly improves battery management
This technology significantly improves charging speed, reduces power loss by 75%, and enables more efficient charging.
Increased capacity by 9%, improved performance and improved battery life to over 8 hours
- charging speed increase good (how many hours to fully charge?) but battery life just over 8 hours??? I would have hoped at least >12hrs.
-The "Intelligent Desktop Mode" technology has also been improved to support batteryless operation by redesigning the battery isolation and power supply. - great, very nice!
・ Improved WTA (Watts Transient Aligned) filter to achieve 40,960 taps (technical indicator of interference filter complexity) using 40 DSP cores. - good, no need to overwhelm us with tap # ;-)
・ Improved noise modulator improves depth and detail, and improved 4e pulse array DAC reduces distortion and out-of-band noise. - still 4 elements, will be interesting how the >100kHz noise floor looks with this; presumably pushed further out if higher order noise modulator.

・ Abolishes coupling capacitors to achieve higher neutrality. - sure...
・ Mojo 2 is designed and manufactured in the UK. Uses a high-quality aluminum housing with a black finish that has been sandblasted.
Mojo 2 is fully compatible with Poly Streamer / Server, allowing you to store and play up to 2TB of solid libraries when using high resolution streaming and microSD card slots.
Overall, this looks like an incremental upgrade. Not much really has changed with the underlying DAC which I think sounds fine already but might have expected more given the 7 years! At this price point and with advancement in other portable DACs, this is actually a bit disappointing. I cannot help but wonder if Chord simply did not want the performance to eat into the higher-end devices by advancing the architecture of their least expensive product, especially with the "desktop mode".

If you need the DSP features like cross-feed and EQ this could be nice. I'm just not sure most audiophiles care too much about this. That "104-bit" DSP spec is clearly for the marketing department; 64-bit would have been more than awesome! How they "spin" that DSP & number in the ads, mainstream audiophile media, and sponsored online content (eg. YouTube channels) could be fun to watch.

Alas, doesn't look like they increased the headphone amp power either by any substantial degree.

A bit confused with the low battery life number and hope it's incorrect - if there's one thing that the last 7 years has allowed, I would have thought it would be this!


  1. fun article! First infos on Mojo 2 are out BTW, although a large part of it reads as if it's been through DeepL translation for some reason

    1. Thanks for the link verifonix,
      Looks like I posted the review/measurements just in time to have this device fresh on my mind to look at the Mojo 2.

      I'll add a little addendum and let's go through the features list!

  2. (Sometimes unfortunately Google messes up with the comments postings... Here's one from Nick which he E-mailed me:)

    Thanks Arch for an exceptionally thorough and useful dissection of the Chord Mojo. There’s much that I can relate to. I’ve owned a Mojo for 3 years, deployed in triple applications:

    - as a DAC in our main audio system. While I doubt Chord’s design team prioritised this application, its high performance makes mainstream home system use a possibility.

    - as a semi- portable DAC/amp driving headphones around the various parts of the house

    - as a pocketable DAC/amp driving IEM’s when out and about.

    Mojo remains a remarkable achievement. From a sound quality viewpoint, both objectively and subjectively Mojo delivers across the board. I love it! However, reinforcing several of your comments, I have found significant practical issues in all three modes of use.

    We live in a moderate to warm climate. When deployed in our main system, Mojo is permanently plugged into power. Even when turned off using the unit’s coloured ball controls, Mojo remains warm. When operating, on warm days Mojo becomes surprisingly hot - uncomfortably hot to touch. In fairness this has yet to trigger thermal protection. However in our climate this mode of use has most probably contributed to the failure of the expensive - and hard to track down - battery in <2 years.

    Deployed as a household headphone amp, Mojo works brilliantly, driving our HD6XX’s with ease. However, as you’ve noted, the micro USB socket doesn’t enjoy frequent re-insertions, and in our case has now separated from the internal PCB, leaving the device inoperable.

    As a portable device, I found the Mojo uncomfortably bulky to be sharing a pocket with an iPhone. Its heat generation was an unwelcome guest on hot days too. Lastly, I’ve lost count of the number of costly and fragile Apple Camera Connect cables that failed to survive the continuous flexing in this pocket environment ( there are some hard to find cheaper cable alternatives, however durability with these remains an issue in my experience).

    In the end, I have given up on the “triple duty” dream. Rather than pay for the Mojo’s micro USB input to be repaired in the UK ( dealers said there were no repair options where I live), and face the ongoing costs associated with replacing its costly battery, I bought a dedicated DAC (Topping EX5) for our main system. For portable use I reverted to my battery-less Audioquest DF Red, which realistically is perfectly adequate to drive IEM’s in an outdoor setting.

    I still look fondly at the Mojo, having enjoyed the listening experience despite its frustrations. It will be interesting to see whether Chord addresses these issues - and others raised by you - in the MK2 version.

    Lastly, thank you Arch for your contribution to sane discussion in the audio community. I’ve learnt a lot from your blog ( and perhaps a few others’ ) over the years. The practical result in our home is a sensibly priced, high performance audio system which above all enables me to thoroughly enjoy ALL my music, ALL the time..



    1. Thank you Nick for the very thorough response!

      I like how you gave the Mojo a shot in all these circumstances and environments! Indeed it looks like from the early Mojo 2 specs that they are going to address the "desktop mode" of operation and the USB-C hopefully will also address the semi-portable side and durability.

      Yeah, given the size and weight, I don't think I'd be comfortable with this in my pocket even if not too warm in the cooler northern climate ;-).

      The Topping EX5 with both single-ended and balanced outputs looks like a fantastic choice for desktop speaker/headphone use!

      As usual, a pleasure testing these things out and I do my best to be "sane" about this stuff ;-).

    2. As the owner of the tested Mojo, I can attest that your *triple duty* dream also falls a bit short from my experience although I've only used it for headphones/IEMs. In short, it's quite a "high maintenance" unit that just becomes a hassle to upkeep.

      In order to prolong the service life of the unit, I've been extremely careful to plug and unplug the micro USB plug with surgical precision, to avoid any kind of twist or lateral force that may loosen/damage the connector over time.

      Also, when at my workstation, I intermittently charge the Mojo while playing for bursts of 30 to 45 minutes at a time to allow cooldown and to try and constantly keep the battery charge between 40-80% and to always avoid constant charging, especially during use. It's a chore and one of the main reasons I went with the Cayin RU6 for the "plug-n-play-n-faggetaboutit" operation for non critical listening.

      As for the portable walkabout with IEMs operation, it's a chunky brick to stuff into your pocket especially tethered to a smartphone. The dongle is the much easier solution.

      I'm thinking of moving to dedicated workstation and portable DAC solutions and the RME ADI-2 DAC is the frontrunner to pair with the RU6.

  3. I almost bought a Mojo a few year's back. I wound up holding off because of the ASR review. It seemed like it was a priced a bit high for what it offered. I'm one of the few that like the Chord marble UI although I think they've overused the theme a bit. On the Qutest it works well for me. One button does the filter selection, which I pretty-much never play with anymore, and the other does input selection, also set to USB for me these days. The little glass viewport tells me that it's seeing different sample rates. Knowing the format and sample rate aren't important. It just gives off a pleasant glow. I find it fun and pleasantly quirky to have the orbs instead of nobs.

    UIs seem like solvable problems compared to the topics raised by truth vs misinformation in the social media age. Not sure how that's going to work out. There have always been scammers, hucksters, and flimflam-ers. The tools have gotten much more powerful to fleece even larger groups of people.

    Our younger generation will be better equipped on the technology front but humans will be humans. We seem to love our clans, camps, clubs, and cliques and have affinity for fantasy over realty. Building your own cult is big business these days. Us vs them is a pretty powerful playbook especially if it offers seductive easy answers. I'm still rooting for the cult of peace, love, and understanding.

    1. Thanks for the note Doug,
      Pricewise, yeah, this isn't cheap and competition within the portable market with the inexpensive DAC dongles is stiff.

      Despite my critique, I can certainly appreciate that folks will like the UI and glowing marbles ;-).

      Yup - "humans will be humans". Online, we'll definitely see examples of the worst and I hope also at times the best of us. Freedom to speak, freedom to express emotions, and alas freedom to be dishonorable (lie/cheat/steal...).

      As much as I also would love to see "peace, love and understanding", unfortunately I have little faith in folks like Neil Young being a good representative. As a person I'm sure he's decent, likable, and can show kindness. What we need these days are leaders with honest integrity, and vision. I just don't see that in my personal or professional life in general with the old "peace and love" generation with more words than wisdom or ability to act.

  4. Thanks for bringing up the LH Labs fiasco and $6M ripoff. Those of us with no recourse are pissed but largely have moved on. Gavin has claimed ignorance to what happened after he left (in an exchange via Linked-In to me) and I think implies some non-responsibility, deferring to Mr. Ho/Hope. Unfortunately, the California DOJ did not bite after a very well crafted 'class-action' complaint was filed and Mr. Ho still seems to be doing business for Tesla car audio and selling IEMs. You mention Stereophile and TAS - I contacted both editors to inform them, hoping for some press but none was to be had. I can't think of a bigger fraud in all of modern audio than this particular crowd funding scheme. On the other hand, MIT launched the Vero headphone cable line through the same Indiegogo platform but delivered in spades, on time, as promised to which I can attest. The LH Labs fiasco is really driven by Mr. Ho and Gavin as classic over-promising and under-delivering (scratch that, about NOT delivering).

    1. Sorry to hear Unknown as one of the folks involved with this company / these individuals.

      The lack of oversight and the inability for any "feedback mechanism" -- whether it be the DOJ (even a slap on the wrist and public notification), even just Stereophile or TAS mentioning this to its readers would have been something.

      I do hope nobody spent too much money into this scheme and are at a place to move on after these years. Caveat emptor...

    2. I'm usually excited to read about stuff that I'm considering or perhaps already own, but this time it was painful to be reminded of LH Labs. I bought two of the first-version Geek Out, and as I was happy with them I also spent roughly $200 on a Geek Wave in 2014 (the existing similar devices were a lot more expensive at the time).

      I realized a few years ago that it would not be as good as I hoped in many ways, but it was only last year that I realized that there would be nothing at all, not counting the 197 status update mails...

    3. Sorry to hear Freddie,
      Yeah, disappointing man... I guess $200 isn't too bad at least. Still sucks I'm sure to even think of this.

  5. If you just could get your hands on an LG G7 or V50 music dedicated mobile phone to see (better listen) whether it is THE ultimative alternative to all these Mojo's things???

    1. Greetings Read,
      I'll keep my eyes and ears peeled for these devices. Admittedly, I don't know many audiophiles interested in phones instead of just an add-on like an outboard/dongle DAC.

      With LG also terminating their cell phone business, these will be very much legacy products.

  6. Though official news not out yet, indeed it looks like those early release specs were correct on the Mojo 2.

    I don't think from a functional perspective this is all that impressive even though they're trying to spin the DSP thing and making claims like:
    "Did you know that all other digital EQ implementations are sonically lossy? I didn’t until speaking with Rob Watts.
    As per Darko in his sneak peek:

    Will be interesting to hear the spin around pairing this with an M-Scaler?

    Incremental upgrades are fine... Just hope the hype is measured and doesn't go too far with new products.

    1. Had a quick peek at Darko's preview because Chord won't let reviews be released until tomorrow.

      So how is one supposed to set the 4 band EQ with 4 glowing buttons. I can't even figure out how to set the EQ with a full screen on the RME ADI-Pro 2!

    2. Good question AudioPhil...

      Check out this "User Instructions" video:

      Lots of colors and button presses to determine the EQ settings! I suspect this is why they made this video. I really don't like this kind of primitive interface. Look at how to go into "lock mode" - press menu button 6 times, then the 2 volume buttons simultaneously. Talk about unintuitive in 2022.

      Yeah, the RME ADI-2 needs a bit of getting used to with the interface even with an LCD screen ;-). Thankfully once you set things the way you like, hopefully no need to fool too much! Compared to the Mojo 2, actually seeing the EQ shape is so much better than toggling the color blobs.

      Will be interesting to see the reviews. Hard to be impressed with this so far and I'll probably go for something else for my office playback. ;-)

    3. One more thought I could not shake looking at this design. It looks like they tried too hard to maintain Poly compatibility. As a result they could not start with a fresh slate for the design; hence retention of the micro-USB.

      Unless people actually feel the DSP function is usable, it's a bit of a waste IMO, especially with that kind of user interface!

      I have a feeling this Mojo 2 will not achieve anything like the sales numbers of the original. I suspect Chord has incorrectly assessed the target audience for a >$600 portable DAC. This seems more like a "Mojo 1.5/SE" for Poly users to me.

      They probably could have just started totally fresh, designed the device aimed at USB-C, improved portability, added balanced output, increased battery life substantially, added Bluetooth and if they wanted to update the DAC resolution, by all means - it's been 7 years! Seems like a missed opportunity to develop a truly kickass update.

      I wonder what kind of marketing research they did for something like this. I could be wrong, so will see whether consumers flock to this.

    4. I totally agree with your points, Arch.

      The Poly was a disaster from the start, and I would tend to think most Mojo users looking for portability when walking about is going to like lugging around a double sized brick in their pockets even if it's untethered from the smartphone. In my opinion, this anchor (both physically and figuratively) is going to drag down the appeal of the Mojo 2to the majority of existing and new owners.

      The whole EQ setting process looks to be a nightmare:

      "Look at how to go into "lock mode" - press menu button 6 times, then the 2 volume buttons simultaneously." -> reminds me of a 90s Mortal Kombat fatality or Mario Kart cheat code. :-)

    5. Hey there AudioPhil,
      I do wonder how many Polys they sold for them to consider compatibility to be high on the list of "must have" features for the Mojo 2.

      LOL... MK fatality.. "FINISH HIM!"

      Will be interesting to see if the reviewers complain about the interface!