Last week, I published Part I of the review/measurements on the upcoming E1DA #9039S USB dongle DAC/headphone amplifier. Already, we've seen that this ESS ES9039Q2M-based balanced DAC produces very clean, high-resolution sound.
As we continue, let's delve deeper into the performance of this little device. We'll have a look at some features like DSD performance and more importantly, let's examine the balanced amplifier output when subjected to headphone-like loads to see how well it performs.
I. DSD
First let's just get DSD over with. 😏
Honestly guys, I rarely use DSD these days because there's just not much native DSD content I listen to regularly (as discussed years ago, many SACDs are just upsampled PCM). Even if a recording is native DSD, it's more than likely just SACD/DSD64 which is rather noisy just above 20kHz whereas resolution at 24/192+ already would be of phenomenal quality with plenty of tools available in the studio for processing.
Upsampling PCM to DSD128+ can be done these days in realtime with software like HQPlayer but IMO the benefits are really not significant compared to DSP in the form of digital room correction or other processes like crosstalk cancellation for example. Since we cannot keep DSD in its native 1-bit format for DSP, multibit conversion is necessary, so we might as well use PCM! Furthermore, for many DACs including these ESS chips, internally we're looking at a multi-bit sigma-delta ("HyperStream IV") modulator which will modify your 1-bit input anyways; perhaps an issue for some DSD purists! (Some DAC chips like the AKM ones have a DSD Direct pathway.)
For testing DSD, let's use my Google Pixel 8 PRO (Android 14) phone with USB Audio Player PRO:
As I mentioned last time, the "zatoichi" firmware that I based my measurements on is able to handle up to DSD128 DoP and one would need to use the non-Zatoichi variant for native DSD playback up to DSD256.
To start, let me grab a reading of a clean PCM 24/96 1kHz 0dBFS off the phone just so we can compare with the DSD output.
"Zatoichi_v02.hex" Firmware:
"9039s_v05.hex" Firmware:
Now let's look at the alternative non-Zatoichi firmware which runs the ES9039Q2M and USB interface chips asynchronously but provides the option of native DSD playback to DSD256:
FFT up to 96kHz. As usual, notice the reduction in ultrasonic noise with higher DSD speeds. |
Tip: This might not be relevant once the final #9039S hardware & firmwares are released. For a couple of nights I was wondering why the non-Zatoichi firmware measured unusually poorly on my test bench. I found out that it was because my "THD DAC" calibration settings and output level got messed up when I flashed the firmware. Easily fixed with the "E1DA_9039_Tweak" app I mentioned last time in Part I. Might want to double check each time firmware changed just in case.
II. Performance as headphone amp
As with any headphone amplifier, the #9039S will need to manage the typical impedances from headsets out there. While many headphones these days have a relatively flat impedance profile, some do vary a bit and there's a whole range of impedance levels so it would be nice for the headphone amp to handle everything from say 20Ω to 600Ω without excess distortion and with adequate power.
As discussed a few years ago, I typically measure loads at 20/75/560Ω levels representative of low/medium/high-impedance headphone loads.
For convenience, I'm going to deviate and start using the E1DA Accessory Load Board. I made a 3.5mm balanced phono-to-test probe/GND cable as seen here:
Here's what it looks like when testing:
Since frequency response is the most important thing to get right, the first thing we must examine is the headphone amplifier's output impedance; the lower the impedance, the better "load invariance" including better damping factor. This can be measured based on voltage drop between the unloaded state and with a low 20Ω load, calculating the output impedance:
With a flat output impedance curve averaging <0.2Ω across 20Hz to 20kHz, I suspect you'll have no trouble driving any sane headphone using the #9039S. While I don't have any balanced headphones with wide impedance swings, we can have a look at the frequency response under various loads and estimate what we might see when a headphone of fluctuating impedance is plugged in:
Notice only 0.5dB range on Y-axis. |
As you can see, I put the cursor at 1kHz so that we can read the dB for each load. Notice that between "No Load" (which would be "infinite" but in actuality 200kΩ for the E1DA Scaler used) and 16Ω is only about 0.1dB. This implies that even if you have a headphone-from-hell that had impedance fluctuations from say 1kΩ to 16Ω across the audible spectrum, all you might hear is an insignificant fluctuation of 0.1dB across the frequency response. This is what "load invariance" looks like.
Beyond frequency response, how does this headphone amplifier perform in terms of distortion under load? Check out these results with a low 16.2Ω load (1kHz tone, -80dBFS stepped sine up to 0dBFS):
Cursor placed at 1Vrms, and -120dB for reference. |
As you can see, there's clipping at 0dBFS/3.5Vrms. But so long as you avoid pushing the listening volume to 100% and music not frequently clipping or hitting peak level (!), the headphone output is able to achieve phenomenal resolution even at -0.5dBFS (3.3Vrms):
Wow! THD+N of -124dB into 16Ω at 3.3Vrms. That's just a mere 1dB reduction from THD+N -125dB unloaded at 0dBFS. At 3.3Vrms, the amplifier is pushing 0.7W into the 16Ω load using this USB dongle.
Let's examine the harmonic distortion performance across the audible frequencies (not just 1kHz) at various output levels:
Very well behaved. As expected with a high-quality balanced device, the even harmonics are well suppressed. Odd harmonics tend to be higher. Note that I'm not able to benefit from the E1DA Cosmos APU (1kHz notch filter) for these loop-back stepped sine THD vs. frequency measurements, hence the THD+N of the 1kHz measurement sits at a "mere" -118dB @ -1dBFS into 16Ω.
Here's my Triple-Tone into 16Ω so we can have a look at harmonic and intermodulation products along with a TD+N resolution score:
-111dB on the Triple-Tone TD+N into 16Ω is excellent. Within the audible frequencies, the highest distortions are below -114dB, nothing of concern. Unloaded, the TD+N measured -117dB so there is a drop as expected, but this is not much given the punishing low-impedance conditions and more complex signal.
As we increase the load, the results are predictably excellent with no clipping to the full 3.5Vrms level. Here are the stepped sine 1kHz graphs into 20.5Ω, 80Ω, and 300Ω loads:
3.5Vrms into 20.5, 80, and 300Ω loads correspond to peak power of 0.6W, 150mW, and 40mW respectively. Often, we see headphone amp specs documenting power into 32Ω - for the #9039S, this would be 380mW which should be more than adequate for the majority of mobile listeners! Obviously, check your headphone sensitivity and make sure to protect hearing acuity if you're in need of high-power headphone amplification. 😐
Since I like to try for apples-to-apples comparisons, let's have a look at the Triple-Tone TD+N result into 20.5Ω at 0.5Vrms:
Distortion products below -120dB. |
TD+N of -108dB in this test is excellent, besting the Sabaj A20d 2022's headphone out which achieved about -99dB and the Drop+THX AAA 789 at -93dB - both of which are full-sized desktop devices that can provide more power even though lower resolution score.
#9039S, world class balanced DAC & portable headphone amp performance in the palm of your hand... Literally. |
III. Final Summary
Taking Part I and today's Part II results together, objectively and subjectively, the E1DA #9039S is a phenomenal performing little USB-powered balanced DAC/headphone amplifier with 2.5mm phono output. The measured performance is in line with some of the highest fidelity desktop DACs. While the final MSRP is yet to be announced, I'm quite sure the price will represent seriously good value for an objectively "super-high-fidelity" audio converter than can handle up to 32/384 PCM and DSD256.
As a little headphone amplifier, the output impedance of <0.2Ω flat across the audible frequencies will mate well with basically any non-exotic headphones without significant frequency variation. The fact that this device is able to maintain low noise and distortion at up to around 3.3Vrms into a very low 16Ω load (0.7W) with better than -120dB THD+N is certainly a remarkable feat!
If you get one of these, digging deeper into the performance, the Zatoichi firmware lineage is best for highest fidelity playback so long as you don't need native DSD256 support (ie. up to DoP DSD128 is probably adequate for the vast majority of listeners). That's really just super nit-picky when we're talking about a DAC that's easily capable of better-than THD+N of -120dB!
As with Ivan's other E1DA line of dongle DACs (like the #9038D6K), there are also opportunities for tweakers to play with the registers as discussed last time. I'm not sure if there will be an Android "Tweak9039" like the Tweak9038 app discussed previously.
Despite the abuses delivered over a number of evenings of testing with different computers, phones, and various loads, this little dongle DAC handled it with grace. Even playing at full volume at extended periods of time into low impedance loads, the metal case only got mildly warm.
Considering that Ivan has been able to squeeze beyond -125dB unweighted THD+N out of this little ES9039Q2M chip that's only specified for -120dB already, I wonder what he can do with the ES9039PRO with specs beyond 130dB dynamic range and even better THD+N or maybe even dual-9039Q2M's?! Will see I guess... I assume he still has his eye on making the larger Cosmos DAC one day. 🙂
--------------------
A few more words on finding balance in audiophilia...
Alright folks, time for Spring Break. Hope you're enjoying your music - whether you're mobile or otherwise!
Can't speak, got a beat in my headphones...
Addendum (March 24, 2024): I received E-mails about the availability of this DAC/headphone amp. The last note I received from Ivan was that he couldn't find the "right solid-polymer flat caps 1000-1500uF in China... So, currently doing re-layout of the PCM to fit alternative caps". Otherwise, "pretty much ready to start"; so I assume coming soon.
Highly recommend checking out the E1DA Discord for discussions.
Addendum (March 27, 2024): I had a listen to the little DAC/amp in the main system tonight. A bit contorted cablewise with using balanced 2.5mm → dual XLR (male) then XLR (female) → TRS Balanced cables to Topping PA5 MkII+ amplifier → Paradigm Signature S8 v.3 front speakers.
That's very impressive, especially considering that it's a USB bus powered device. Out of curiosity—did you also try measuring using your RME as an ADC? I hope, there is no "equipment bias" due to the fact the entire measurement chain is from the same manufacturer :)
ReplyDeleteHi Mikhail,
DeleteYeah, that's amazing performance! Even if not USB powered, I don't know which other headphone outputs would be able to achieve better than -120dB THD+N into 16-ohms.
Yup, one evening I did use the RME to do a quick measure to make sure the set-up was good; this was when I was fooling around with the tweaking (discussed in Part I). Clearly the resolution of the DAC was beyond what the RME could measure without using a notch filter!
Archimago,
ReplyDeleteYou hit upon this subject in regards to measuring vanishingly small differences in DAC performance but..
To me seeing all these measurements, and the amount of time folks over on ASR spend measuring DACs, it's almost like the audiophile version of Phantom Limb syndrome. We used to have analog sources - turntables, cartridges etc - which not only measured quite different but were often way in to the audible zone, so this stuff really mattered. But once we moved to digital, well, it got mostly academic. But audiophiles still have to scratch that phantom limb itch of measuring stuff, whether there are audible differences or not.
The same goes for the "subjectivist" side as well: once we got essentially transparent/accurate digital sources did all the tweak stuff stop? Of course not. Subjectivist/golden eared audiophiles have found every which way to "improve" the sound of digital with all manner of whacky implausible tweaks.
For me digital is a done deal. I have a Benchmark DAC2L. I never have to think about digital again.
Hey there Vaal,
DeleteCertainly can appreciate your position and I agree as well. After testing a number of DACs and running blind listening myself - volume controlled, removed as much other variable as possible - the differences between DACs are clearly at best subtle so long as the measurements indicate that we're listening to bona fide "high-fidelity" DACs without unusual distortions primarily in the frequency domain (time domain accuracy of course beneficial, but nowhere as important unless severely anomalous!).
Yup, the Benchmark DAC2L has all the characteristics of an excellent DAC capable of hi-res performance so I would have no concerns soundwise and could happily be a "forever DAC"! No... There is no subjective "magic" in the technology itself; as I've suggested for years, the "magic" lies with the artists and how they convey their art to use as we enjoy the music, not what some "iconic" audio designers believe they delivered to the consumer.
Love the "Phantom Limb" analogy :-).
This is why over the last year I haven't been measuring as much DACs and spending more time with the inexpensive TI chip amps or talking about "immersion". Unless there's something likely new I can experience and demonstrate (like this E1DA headphone amp pushing the boundaries of resolution into low impedance loads!), I've actually declined a few offers from companies wanting to send me products for review.
I think it's good that the ASR guys continuing to publish the data; this puts useful pressure on companies that are not actually putting out good technology but still advertising as "high-fidelity" or "high-resolution" since these terms have an objective definition we should as an audiophile hobby be vigilant about (rather than that silly "high end audio" term which is mostly about just spending disposable $$$$ and bragging rights).
Well I have ordered one, so the question is now academic, or I'll find out soon enough, however:
Delete- Did it get hot delivering so much power?
- What was the current drain on USB source, did you measure?
- Since it can output 3.5V RMS (5V ptp), can it maintain that for any length of time? I mean USB is 5V, to maintain rail-to-rail output is mighty difficult, and I know it has large storage caps. to help maintain the rail, but after a few seconds, what happens?
Thank you
The answer to my own question:
DeleteI asked the source, here is the answer,
" Max is 650mA (measured) supplying max power to a 16 ohm load (700mW + 700mW). Volume and load dependent. "
Also, the device gets a bit warm. Part of the reason is that, there is a 6.25V SMPS PSU built in, to accommodate such high power output. (if I understand correctly)
DeleteI was wondering, how he had managed to get so much power out with a mere 5V USB supply!
Hi Archi,
ReplyDeleteAre you going to try to listen to music with this tiny DAC on your main audio system with speakers? I would be interested to know your impressions to see how it sounds with big speakers.
Hey there fgk,
DeletePosted a little addendum on this. Sounded really good with the Google Pixel Pro 8 phone and USB Audio Player PRO; clean sound connected to the Topping PA5 Mk II+ amplifier.
However some issues with crackling noise using that set-up with other devices so I would not recommended at least with that balanced Topping amplifier combo. Might be better with other amplifiers or maybe using USB isolator with the computer (didn't check). I suspect it's the grounding and will need to double check.
I would stick with using this for headphones as intended...
What about LTE interference noises? It's been a consistent "feature" of all previous E1DA DACs which kinda ruins the point of using them on the go.
ReplyDeleteI can't hear any LTE static noise with HFM HE400i or Sennh HD650, silence In any conditions. 9039S handles these cans VERY, almost painfully loud at 0dbfs. But I slightly hear that with 118db/mW 20ohm IEMs with a particular cable angle, if place the phone under my grounded metallic desk. However, the idea of using such sensitive IEMs with the DAC 600mW output clearly has no sense.
DeleteThis comment has been removed by the author.
ReplyDeleteHi
ReplyDeleteThanx for the review.
Since this is a high power dongle, and the juice from the USB (phone?), did you check the current drainage?
I'd like to know, how long my phone lasts during a flight.
Bless