REVIEW: E1DA #9038D6K Dongle DAC / Headphone Amp (Part II): Headphone Amp Power, DSD, Subjective Impressions, AMPT & Perfectionistic Tweaking!

A great sounding music listening station! (Samsung Galaxy Tablet, Drop+HiFiMan HE-4XX, classic Jacky Cheung cantopop.)

Okay friends, today we continue with Part II of the discussion on E1DA's #9038D6K portable DAC/headphone amp. Please refer to Part I last time for the general overview of DAC performance which already tells us about the PCM resolution of the device. The data from last time shows that for the price and size, this unassuming dongle is one heck of an accurate, high-fidelity, high-resolution digital-analogue converter.

This time, let's move forward with exploring other areas not yet discussed. Specifically, let's focus on resolution when under headphone-like loads, look at DSD performance characteristics, have a listen to the DAC, and given that E1DA is known to be tweaker/DIY-friendly (including making devices like the Cosmos line), let's also talk about what I would consider more "extreme" tweaking for the perfectionist audiophiles!

REVIEW: E1DA #9038D6K Dongle DAC / Headphone Amp (Part I) - PCM DAC performance. And (potentially) higher dynamic range in Spatial Audio 2-channel fold-downs.

Little E1DA DAC to Sennheiser HD800 headphones via 1/4" adaptor... Looks ridiculous if walking around in public with this! But sounds great. ;-)

A few weeks back, I received a package from Ivan Khlyupin (IVX) of E1DA containing both the Cosmos Scaler and the device we'll be looking at today - the E1DA #9038D6K DAC / headphone amplifier.

This is the latest iteration of the #9038D models which feature 3.5mm single-ended output, to be distinguished from the #9038S models which are balanced devices with 2.5mm output jacks. And the "6K" refers to 6000μF (!) of power rail filtering (original #9038D has 4000μF).

As the name implies, internally, these DACs are based on the ESS ES9038Q2M low-power chips. They are capable of playing back PCM to 32/384 as well as up to DSD256. Over the last year or two, we've seen a proliferation of DACs based on this component and I would say that overall, the performance on these devices have in general been very good. Thanks to the low power consumption, we can now have mobile converters that perform at least to the resolution of many desktop DACs while being fully USB-powered.

To generate the amplified headphone output, op-amps used include the OPA1622 and OPA1602 based on the E1DA specs. To achieve very high resolution, internal components are advertised to be quality Susumu resistors, Murata C0G caps, Kyocera AVX tantalum caps, and connectors from Taiwan. In my discussions with Ivan, I know in the last while it has been slow for him to source some of these components and at times difficult to avoid fake parts out there!

REVIEW: iFi GO Bar - Portable DAC / Headphone Amp (Cirrus Logic DAC, Balanced & Unbalanced).

My friend AudioPhil is really into his headphone gear. Recently he acquired the product above and asked if I might want to play with this for a few days... Sure, this looks interesting!

This is the new iFi GO bar (around US$320), a portable headphone DAC/amp. The USB interface is a USB-C form factor (480Mbps USB2.0 Hi-Speed), and there are outputs for single-ended/unbalanced 3.5mm TRS and balanced 4.4mm pentaconn. Interestingly, the company (iFi, subsidiary of AMR/Abbingdon Music Research) does not specify which DAC chip is used inside. Suspicion is that it's likely the Cirrus Logic CS43198 or CS43131, both are recent chips circa 2017 capable of "pseudo-differential" outputs and low-power consumption <40mW with rated THD+N of -115dB, DR 130dB, maximum PCM 32/384, and DSD256. The specs look good but don't get too excited about these ideal numbers when implemented in a USB dongle.

I don't know what's the point of being so secretive about the DAC chip used (Crutchfield says it's the 43131).

MEASUREMENTS: Soditer "Fourth Generation" USB Type-C Headphone Adaptor (Realtek ALC4042).

These days, many recent smartphones no longer include analogue headphone jacks. Implicitly, the idea is to favor wireless Bluetooth headphones instead. As a result, if you want to hook up your wired headphones, one would need to buy a headphone adaptor which may come with your phone (for example, Apple at the beginning included their Lightning to 3.5mm Headphone Adaptor and these days may include some Lightning EarPods).

Recently, I upgraded my phone to the Huawei P30 Pro which does not have headphone output, so I was in the market to get one of these for the phone's USB Type-C digital connector.

Many of these headphone out / DACs are inexpensive, and the adaptor I have here today - the Soditer USB Type-C Headphone Adaptor - ~US$25, is advertised as supporting hi-res playback (even up to 32/384), and is claimed to provide up to 35mW into 32Ω headphones. Let's have a look...

MEASUREMENTS: Audioquest Dragonfly Black 1.5 - PART 1 (General)

Four USB mini-DAC's (back to front): Light Harmonic Geek Out V2, Audioquest Dragonfly Black, SMSL iDEA, AudioEngine D3.

As I showed a couple weeks ago, I have in my possession one of the Audioquest Dragonfly Black DACs for testing. I'm actually borrowing it from a friend so it's not going to be in my possession for long... Long enough for me to listen and run some objective testing to see what the "deal" is.

I think it's useful to show these test results on the Dragonfly because AudioQuest clearly has a healthy advertising budget and promotes it quite heavily on audiophile sites with ads in magazines as well; as such it's a bit of a "standard" even though a number of other alternatives exist. For example, a few weeks back, I showed the measurements for the SMSL iDEA which I thought performed objectively amazingly well for such a small device although I had some issues with seamless connectivity to Linux / Android. As you can see in the image above, I have tested a few others of these kinds of  DACs already including the AudioEngine D3 measured in 2014, Light Harmonic Geek Out V2 in 2015, and also the previous revision Dragonfly v1.2 in 2014 which I don't have on hand any more (it was given as a gift to a friend).

MEASUREMENTS: SMSL iDEA USB DAC / Headphone Amp (ESS Sabre ES9018Q2C + XMOS XU208)

In 2015, ESS revealed its latest generation of DACs at the CES show. One of the interesting new products revealed was the SABRE9018Q2C, a tiny 5mm x 5mm SoC claiming very high audio quality out of an integrated DAC/headphone amp operating with low power along with the ability to decode a wide range of sample rates.

I was contacted by ZugZugOrc on Computer Audiophile to have a look at a recently released USB DAC he wanted to buy for some measurements based on the above chipset. So we made an arrangement where he sent the package to me to have a look at and subsequently after I'm done, I would send it off to him to use :-). Thanks Zug for the opportunity!

Here's the device - the SMSL iDEA (can be found on Amazon for ~US$86 currently), a mini USB powered "stick" based on the ES9018Q2C "audiophile-quality" mobile DAC capable of accepting up to 32/768 and DSD512!

SMSL stands for  "ShuangMuSanLin" Electronics Company based in Shenzhen, China. I was sent the black one, but the device is also available in red.