Yulong Aquila II DAC and Headphone Amp Review

[PeteL]

From the top of my head, SMSL SU-8, SMSL D1, SMSL M400. All DACs though, not dac+amp. If you look at teardown it is easily recognisible:
View attachment 83192

I don’t really count the D1 and M400 in the same price range, since they are only DACs as you said, and in the 1k range. For China, it’s Hi end. The SU-8 honestly I don’t find this info, but if you say, I believe you, maybe my google skill is weak, but it really does surprise me at this price.

 

[diegooo1972]

I think it's just the price here. If you don't need balanced or aes You must consider that SMSL sanskrit 10th + Archell 2 pro give you absolute performance for 250 buck. 400$ more buck for aes and balanced it's arguable. And still for 200buck you can have balanced and 2xadc with Motu M2 with fair HP out. I understand Amir rating but I don't dislike this dac too. Just too expensive imho. I must agree with Amir.

 

[Veri]

I don’t really count the D1 and M400 in the same price range, since they are only DACs as you said, and in the 1k range. For China, it’s Hi end. The SU-8 honestly I don’t find this info, but if you say, I believe you, maybe my google skill is weak, but it really does surprise me at this price.

It's because SMSL can have the already developed high-end tricks trickle down in their more budget offerings. But there is also downside to FPGA reclocking, people often complain of losing the lock with (jittery) optical signal from their TV.

 

[PeteL]

It's because SMSL can have the already developed high-end tricks trickle down in their more budget offerings. But there is also downside to FPGA reclocking, people often complain of losing the lock with (jittery) optical signal from their TV.

Yes, if the incoming clock fluctuate you'll benefit, but if the clock drift you'll lose it.

 

[Ron Texas]

The red box is pretty and the features are there. How good does it have to measure? Thank you @amirm for another great review.

 

[MediumRare]

Only reason why I didn't get the DX7 was because of the output impedance

My headphones are planar and have flat impedance, so not an issue. You’d have to have pretty extreme cans for any difference to be audible.

 

[MediumRare]

Great review as always.

I thought it was a pretty good AK4493 or AK4497 implementation before I checked on their shop.
It's.... actually 9038pro....Oh well that jitter performance is unacceptable. And how is the SINAD performance so poor.....

With great respect, other than for a top-level engineer like you, on what basis is jitter -127 dB unacceptable?

 

[Veri]

My headphones are planar and have flat impedance, so not an issue. You’d have to have pretty extreme cans for any difference to be audible.

Definitely IEMs, but also very sensitive dynamic headphones, could change FR from the 10Ω SE / 20Ω BAL impedance output often seen with unoptimised headphone amp circuits. For a lot of headphones it's totally acceptable though.

With great respect, other than for a top-level engineer like you, on what basis is jitter -127 dB unacceptable?

Going to have to agree. See Oppo UDP-205, same jitter sidebands. Amir says its due to "low frequency reference voltage modulation". Not an audible problem whatsoever. Agreeing with John that the THD+N (disregarding jitter for a moment) seen here is not particularly impressive for an ESS 9038Pro chip, though. See comparison with these popular units. Besides higher headphone amplifier output wattage, there is no clear advantage seen here in this Aquila unless you need a really beefy dac/amp all-in-one unit.

 

[PeteL]

ASRC and internal PLL are the best things about ESS based chip(as well as no pop). They completely eliminate jitters of any kind. Hence in no way anyone should disable them and implement their own inferior versions of them.
Using AK based chip is a different story.

I'm not expert on the ess chip, but isn't "eliminate jitter of any kind" a bit strong? No matter how good PLL implementation is, it still need a external reference master clock, It can only be as good as that, no? As with anything, the performance of the DAC chip alone will not fix a poor design, the rest of the design has to follow and bottlenecks are rarely on the DAC chips in my opinion, you can really good jitter performance on AK chips, No? Not to pretend I know better here, just how I see it.

 

[JohnYang1997]

I'm not expert on the ess chip, but isn't "eliminate jitter of any kind" a bit strong? No matter how good PLL implementation is, it still need a external reference master clock, It can only be as good as that, no? As with anything, the performance of the DAC chip alone will not fix a poor design, the rest of the design has to follow and bottlenecks are rarely on the DAC chips in my opinion, you can really good jitter performance on AK chips, No? Not to pretend I know better here, just how I see it.

In practical sense in the DAC output, -150dB in Jtest is virtually none.
You would need way more to do the same on AK. And in contrast doing much worse with ESS chip using inferior implementation is what's bad.
DAC chip won't fix poor design but ESS chips allows simplified design but achieving extremely good performance.

 

[JohnYang1997]

With great respect, other than for a top-level engineer like you, on what basis is jitter -127 dB unacceptable?

-127dB is acceptable in a 4493 design but not 9038pro.

 

[JohnYang1997]

Definitely IEMs, but also very sensitive dynamic headphones, could change FR from the 10Ω SE / 20Ω BAL impedance output often seen with unoptimised headphone amp circuits. For a lot of headphones it's totally acceptable though.


Going to have to agree. See Oppo UDP-205, same jitter sidebands. Amir says its due to "low frequency reference voltage modulation". Not an audible problem whatsoever. Agreeing with John that the THD+N (disregarding jitter for a moment) seen here is not particularly impressive for an ESS 9038Pro chip, though. See comparison with these popular units. Besides higher headphone amplifier output wattage, there is no clear advantage seen here in this Aquila unless you need a really beefy dac/amp all-in-one unit.

Considering UDP-205 was basically the first 9038pro design on the market, I would give it a pass. And oppo was no BS no mumbo-jumbo brand. The performance lived up to the expectation.

 

[MediumRare]

-127dB is acceptable in a 4493 design but not 9038pro.

Can you explain why? From a user’s point of view, I mean.

 

[JohnYang1997]

Can you explain why? From a user’s point of view, I mean.

That was from engineering point of view. From a user's point of view it's of course fine. Just like any other cheap dacs with acceptable performance. Modius, Sanskrit, M300mkii, D10s(if balanced is not necessary) all make good DACs. And I also think the amp on this unit is quite good, quite powerful. I didn't say this was a bad product just from engineering point of view I expect much much more from a design with 9038pro in 2020. And if this was 4493 I would say it is pretty good.

 

[MediumRare]

That was from engineering point of view. From a user's point of view it's of course fine. Just like any other cheap dacs with acceptable performance. Modius, Sanskrit, M300mkii, D10s(if balanced is not necessary) all make good DACs. And I also think the amp on this unit is quite good, quite powerful. I didn't say this was a bad product just from engineering point of view I expect much much more from a design with 9038pro in 2020. And if this was 4493 I would say it is pretty good.

Thanks for the clarification. To me, "unacceptable" has a very strict meaning. I’m glad, as a Topping owner, that any lapse in performance is "unacceptable" to you!

 

[PeteL]

-127dB is acceptable in a 4493 design but not 9038pro.

Yet, the adi-2 fs achieve -140 dB with a 4493 (it should, if they took the step of adding femto second to their model name). Some of your own are in this ballpark as well. With this particular review here, Amir states that the jitter distortion bands are caused by power supply. I'll be the first to admit that I do not have full understanding of how he reach this conclusion, I'll research more on J-Tests, but if it's the case, there is not much a reclocker would do to fix that right?

 

[JohnYang1997]

Yet, the adi-2 fs achieve -140 dB with a 4493 (it should, if they took the step of adding femto second to their model name). Some of your own are in this ballpark as well. With this particular review here, Amir states that the jitter distortion bands are caused by power supply. I'll be the first to admit that I do not have full understanding of how he reach this conclusion, I'll research more on J-Tests, but if it's the case, there is not much a reclocker would do to fix that right?

Not very sure tbh. The sideband is way over 50/60hz that it shouldn't be supply modulation(which I have experienced and level is under -150dB). If it's the AVDD modulated by something else it's possible but unlikely. As not seen in most other well designed 9038q2m and 9038pro based units, I would only blame what's being different.
EDIT: It does look like the side bands are 60hz 180hz modulation.

 

[YSC]

That was from engineering point of view. From a user's point of view it's of course fine. Just like any other cheap dacs with acceptable performance. Modius, Sanskrit, M300mkii, D10s(if balanced is not necessary) all make good DACs. And I also think the amp on this unit is quite good, quite powerful. I didn't say this was a bad product just from engineering point of view I expect much much more from a design with 9038pro in 2020. And if this was 4493 I would say it is pretty good.

No offense here and stated with my respect on your ability to push up all those goodies. from internal view of the Yulong Dac it looks like although tidy, it did cramp everything tightly with dual transformer and the analog volume and FPGA for iOS and Android compatible USB input, I am no engineer of any sort and basically knows nothing about design in circuit, but can it be just a design choice for good enough SINAD and Jitter with functionality and performance? kinda of your PSU choice in the A90 which itself omits an almost 10k hz noise in the unit or the DX7 pro where it might have adverse effect with the high output impedence?

To be stated first: I never owned and liked the Yulong products, and as a layman consumer it feels more than acceptable for me to recommend this to any friends who demands the all in one unit which can be used with phone/ tablet as well to drive basically anay headphone in the market?

 

[garbulky]

This is a review and detailed measurements of the Yulong Aquila II USB DAC and headphone amplifier. It was kindly purchased by a member and drop shipped to me for testing. It costs US $640.

The Auila II breaks the mold of rectangular boxes for desktop DACs with compound angles:

View attachment 83117

The volume control also navigates the menus by first pushing it in multiple times until you land on the on screen item to modify and then turning the dial. The display is IPS and has very fine resolution which I appreciated.

The back panel has the usual connectivity:

View attachment 83118

The unit was plug and play with Windows over USB connection. Operationally it ran somewhat warm but no worse than other high performance DAC and amps.

Balanced DAC Audio Measurements
For the DAC portion I focused on performance of the XLR output only. Here is our dashboard:

View attachment 83119

Two years ago I would jump with joy at such low distortion and noise rating as reflected by the SINAD. But today, SINAD of 111 dB is not very competitive:

View attachment 83120

View attachment 83121

Noise by itself seems to be a bit of an issue:

View attachment 83122

This reflects just the same in IMD distortion versus level:

View attachment 83123

The DX3 Pro (dashed blue) is one third the price so having more noise than it is not very good.

There is some jitter that is caused by power supply noise:

View attachment 83124

Not remotely an audible issue though.

An option people wondering about has been the ASRC mode being on and off. This is exposed in Auila but as you see, it made no difference with USB as the source.

Linearity was very good:

View attachment 83125

There are only three filters exposed:
View attachment 83154

I used the sharp one for the following test:

View attachment 83127

Company measurements are a few dBs better than what I am getting (0.0002% versus 0.0006%). I don't know what explains the discrepancy.

Finally here is our multitone:

View attachment 83128

Headphone Amplifier Measurements
Good bit of power is provided especially in balanced mode:

View attachment 83129

Alas, once again noise is higher than it should be. The volume control is analog though (but digitally controlled) so perhaps at lower settings it would show less noise.

Here is unbalanced performance into 33 ohm:

View attachment 83131

I did not have time to listen to it but I suspect it will sound good given the ample amount of power as long as you don't use an overly sensitive headphone/IEM.

Conclusions
Expectations is everything and at this price, I expect "instrument grade" measurement results and sadly we don't get it. Subjectively it will sound fine with its powerful headphone amp. So if you like its looks, it would make an OK purchase. It doesn't meet the bar for me though from engineering point of view so I can't recommend it.

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As always, questions, comments, recommendations, etc. are welcome.

Have to help my wife can more tomatoes but took a break to do this review. Shows you how much I value the money you all put in my pocket! So donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

We are getting spoiled, having difficulties seing this as an unrecommended product. It's got a Sinad in the first tier, It looks good, It's a dac, a fairly powerful head amp and a preamp with balanced out AND AES/EBU in.("The back panel has the usual connectivity") is it THAT usual to get those features for this price?

I think the 700 mw output at 300 ohms is fantastic. That should easily cinch a Recommend imo. It makes it a more flexible and practical unit on top of great measurements

 

[JohnYang1997]

No offense here and stated with my respect on your ability to push up all those goodies. from internal view of the Yulong Dac it looks like although tidy, it did cramp everything tightly with dual transformer and the analog volume and FPGA for iOS and Android compatible USB input, I am no engineer of any sort and basically knows nothing about design in circuit, but can it be just a design choice for good enough SINAD and Jitter with functionality and performance? kinda of your PSU choice in the A90 which itself omits an almost 10k hz noise in the unit or the DX7 pro where it might have adverse effect with the high output impedence?

To be stated first: I never owned and liked the Yulong products, and as a layman consumer it feels more than acceptable for me to recommend this to any friends who demands the all in one unit which can be used with phone/ tablet as well to drive basically anay headphone in the market?

View attachment 83227

It's a good product, the amp section is very capable. And yes transformer interference can have an impact on performance. Now it does seem that the thing on jitter is power supply interference.