Review and Measurements of Topping DX3Pro DAC and Headphone Amp

[777]

also weird thing in @amirm's test is that in the first graph it shows a 0.0004% THD+N for 1Khz tone. However, in the THD+N versus frequency graph it's greater than 0.001% at 1KHz. Are these tests well conducted?

One test it is with 20khz bandwidth and the other test it is with 90khz bandwidth. If we suppose to have an 10Mhz bandwidth FFT test, then THD+N percent will increase very much with stock power supply adapter because of the HF noise. The same problem with random jitter. Depends how much do you want to see in a frequency band. For example Benchmark DAC 3 has the same THD+N in both bandwidth. Why ? Because they care about HF noise. You will see ferrites on the outputs and inputs.

 

[pwjazz]

That's an entirely different conversation. Are you really calling the Dx3 overpriced for its functionality? If so, buy what makes you happy. I am pretty impressed with everything this devices does for the price, given its excellent measured performance. There is no right choice for everybody, but that goes both ways, for some other people the dX3 might the be that product. For me, it wasn't BTW.

Haha, no I wasn't calling the DX3 Pro overpriced! I was specifically responding to your general point about the existence of overpriced goods. I find that in audio, there's a certain strain of thought that regards higher priced products as desirable purely because of their high price and not some objective measure of their capabilities, which is kind of like a Veblen good.

 

[simonchretien]

Since a lot of people were talking about power supply, any idea if running it from a linear power supply like a cheap TeraDak would be worth it?

 

[Philip123]

This is a review and detailed measurements of the brand new, Topping DX3Pro DAC and headphone amplifier. The company kindly sent me a pre-production unit. I usually buy my Topping products unless they are not available in the market as was the case here. The retail price will be $219.99. I expect production to start soon given the high finish of the unit I have.

It is hard to fall in love with budget desktop audio products but there are exceptions and this is one of them. The Topping DX3Pro is darn cute!

View attachment 16777​

The yellow LED as with the Topping D10 adds a much needed touch of color and uniqueness to the unit. The volume knob adds more to that sauce, making for a small box and you enjoy glancing at on your desk.

Surprising for a small unit, as seen in the picture, you get a remote control and all the functionality in its larger brother, the Topping DX7s. You can select the volume control to apply to line out, headphone out or both. So you could use this to drive powered speakers for example without a need for pre-amp and use the remote control as needed.

There is USB input of course and Toslink. For coax input, you actually get two of them! So if all of your sources are digital, you have a nice little pre-amplifier on your hands.

The volume control is digital of course and steps in 0.5 dB linearity all the way down to -99 dB.

There are selectable gains for the headphone out (0 and 9 dB) and filter settings. The unit supports PCM up to 768 kHz and up to DSD512.

Power is provided through a small switching power supply (double the size of typical phone chargers). All of my testing was performed using the provided power supply.

Setup was plug-and-play and I was relieved to see full compatibility with ASIO4ALL at 24 bit depth allowing me to proper test the unit without installing any drivers. Listening tests were performed using WASAPI interface in Roon.

The heart of the unit is the AKM AK4493 DAC chip. This is a departure from most of the Topping DACs (and many Chinese manufacturers) which use ESS DACs.

I am sure you all are anxious to know how it measures so let's get into that.

Measurements
Since the Topping DX3Pro is both a DAC and headphone amplifier, I am going to show performance using both output starting with the DAC section:

View attachment 16778

We have our nice nominal output of 2 volts. Distortion/SINAD is very good, and solidly in "tier 2" ranking of DACs I have tested:

View attachment 16779

So not state-of-the-art but very competent nevertheless.

Dynamic range falls in the same bucket:
View attachment 16780

Let's look at intermodulation distortion versus level:

View attachment 16781

Ah, we are finally free of the "ESS hump" at mid-levels. In this regard, except when we get to highest output levels, the DX3Pro beats even the Topping D50!

ESS really needs to pay attention to this situation and remedy whatever is causing that rise in mid-levels in their OEM designs.

Jitter and noise is busy but for a reason:
View attachment 16782

Until recently, I have not been running the J-test signal in full resolution. I have changed that now and the 250 Hz square wave in it shows interference between digital section and analog as seen by those series of spikes. Fortunately almost all are less than 120 dB so not an audible concern at all. Likewise the two that hug our main tone despite being at -110 are totally masked by the main tone at 12 KHz so inaudible.

Frequency response is boring (in a good way) and flat to -0.2 dB (spec is 0.5 dB):
View attachment 16783

THD versus frequency shows somewhat higher noise levels:
View attachment 16784

This is impacting linearity measurements:
View attachment 16785

That smooth exponential rise is just the noise floor of the DAC dominating. So it is not an offset error as we see many times (with jagged output). All else being equal, I rather seen noise here than non-linearities. I think this is a limitation of the AKM DACs relative to ESS parts.

Now let's switch outputs to headphone socket and see our dashboard view in low-gain/unity gain mode:
View attachment 16786

Pretty excellent! This is at max volume yet we get slightly better performance than even line out! SINAD rises to 108 from 106 dB.

Most of Topping products with headphone output have impedance of 10 ohm. That is dealt with now in DX3Pro:

View attachment 16787

My measured impedance is usually higher than manufacturers due to use of more wires, etc.

The low impedance of 1 ohm means just about every headphone can be driven by the DX3Pro without fear of its frequency response being impacted.

Let's see the power output versus distortion using 300 ohm load:

View attachment 16789

Clipping never really sets in and as such, the output is distortion free all the way to max! SINAD even in high gain mode stays above 100 dB which is superb. This means if you have a 300 ohm headphone like Sennheiser HD-650, you can turn up the volume as much as you want and any distortion you hear is that of the headphone or the source.

Switching to 33 ohm load, we get far more power as expected:
View attachment 16790

We have half a watt using high-gain mode but we do clip past that. Topping spec is 1 watt at 1% distortion which is inline with my measurement.

In low gain mode you are distortion free up to max volume with power up to 0.12 watt.

Finally, let's look at channel imbalance versus volume control position:
View attachment 16791

As expected, the digital volume control produces perfect response with essentially zero imbalance until you get to max volume attenuation of 99 db. No headphone amplifier using analog volume control comes remotely close to this kind of performance.

Listening Tests
I started my testing with Sennheiser HD-650 in high gain mode. Here, there was plenty of power and no hint of strain from the amplifier. Tonal response remained constant up to max volume which was quite loud. But not loud enough to make the cups flap in the wind.

Flapping of the cups was to come though the moment I switched to HiFiman HE-400i. Power was amazing and clarity was superb. As I type this review I have been listening to this setup and it could not be more satisfying.

Conclusions
As usual, Topping shows that it uses proper measurements and engineering talent to design its products. As with their other products, it is next to impossible to find many flaws in anything I measure. Yes, it is not state-of-the-art in all measures and falls just shy. But it makes up for it with its superb headphone stage with very low distortion levels, perfect channel matching, and lots of power coming from such a small package and power supply to feed it.

The switch from ESS to AKM has provided relief from intermodulation distortion that we have been seeing in so many DACs. Yes, there is a slight rise in noise as levels get down, impacting linearity measurements. That is a very worthwhile trade off in my book and I am glad Topping has made the change.

All in all, the DX3Pro does not obsolete every DAC and headphone amplifier out there. But it comes darn close and nails the functionality and performance needed in a moderately low cost unit. Add to that the attractive industrial design and it easily becomes one of my favorite desktop products. As such, I recommend the Topping DX3Pro wholeheartedly.

EDIT: A problem has been noted in early shipments whereby the muting relay clicks on and off excessively during seeking, playing different content, etc. I have not been able to duplicate this on my unit but have reported it to Topping as have others.

EDIT 2: Topping released a new firmware to deal with excessive relay clicking. See: https://www.audiosciencereview.com/...dx3pro-dac-and-headphone-amp.4967/post-127719

As always, all questions, comments and criticism is welcome.

-----
If you like this review, please consider donating funds for these types of hardware purchases using Patreon (https://www.patreon.com/audiosciencereview), or upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).

Awesome review! I just purchased the Topping DX3 Pro on Massdrop and am looking at possibly purchasing the BeyerDynamic DT 990 Premium 600 Ohm headphones. Do you think this Topping has enough power to properly drive the 600 ohm version?

 

[777]

Again, to prove your theory you need an audio analyzer.

Until then, I was playing 0dB of music, so I am very sure about status of the output relay which was "ON". Guess what ? The HF noise of the adapter power supply was there again. For the reference you have and the noise of the oscilloscope.

 

[777]

Until Amir could, look at that:

 

[kukocz]

Until then, I was playing 0dB of music, so I am very sure about status of the output relay which was "ON". Guess what ? The HF noise of the adapter power supply was there again. For the reference you have and the noise of the oscilloscope.

Could you add third graph with lab supply instead of stock power adapter?

 

[777]

And USB jitter for adapter (a1) and Lab power supply (L1). The differences between them it is 3dB or 4dB in favor of the Lab linear power supply. Stock power adapter it is more than ok for most of the listeners, but the hardcore audiophiles can squeeze out all the quality from the dac with a good linear power supply. That's my opinion, good or bad.

 

[777]

Could you add third graph with lab supply instead of stock power adapter?

Ok, just a minute.

 

[dkinric]

Awesome review! I just purchased the Topping DX3 Pro on Massdrop and am looking at possibly purchasing the BeyerDynamic DT 990 Premium 600 Ohm headphones. Do you think this Topping has enough power to properly drive the 600 ohm version?

Based on my experience with 300 Ohm HD-6xx, I would say - it depends. Will it drive those 990s to reasonable listening levels to enjoy the full audio spectrum? Most likely, yes. Will it drive it to ear flapping, as loud as you could ever want it levels? Maybe not. Depends on how loud you like to listen.

For me, near the top of the output, it is nice and loud, but occasionally I find myself wishing for more power. Others here with the same setup (@300 Ohms) have said it is more than enough power for them. I'm outputting from Iphone - Camera connection kit - USB input. Not sure if different signal chains would affect max volume.

The good news is it excels as a DAC, so you can always add a JDS Atom or even THX AAA 789 amp later on.
Don't forget to change to high gain when you get it if using with high impedance headphones.

 

[amirm]

Awesome review! I just purchased the Topping DX3 Pro on Massdrop and am looking at possibly purchasing the BeyerDynamic DT 990 Premium 600 Ohm headphones. Do you think this Topping has enough power to properly drive the 600 ohm version?

I don't have a 600 ohm headphone so can't say for sure. But guessing the answer would be yes.

 

[AresHarvest]

I've combed through this thread, and I still don't understand why there are two seemingly current (but differently numbered) versions of the driver available.

• v4.14 is the latest one with a dedicated entry on Topping's support page (dated 2018-11-20)
• v4.47 doesn't have its own entry, but it's available through a link in the entry for the latest firmware update (dated 2018-12-17)

Can anyone shed some light on this? Maybe it's been covered already and I missed it, but I did look.

 

[SiW]

Awesome review! I just purchased the Topping DX3 Pro on Massdrop and am looking at possibly purchasing the BeyerDynamic DT 990 Premium 600 Ohm headphones. Do you think this Topping has enough power to properly drive the 600 ohm version?

I have DT990 Edition 250ohm version with the DX3Pro and its great

Using low gain with level around -15 and its plenty loud for me.

 

[777]

so it doesn’t improve thd+n at all, as far as I can see from the values.


what's the difference between https://www.audiosciencereview.com/...ac-and-headphone-amp.4967/page-98#post-139794 and https://www.audiosciencereview.com/...ac-and-headphone-amp.4967/page-96#post-139528 ? is the latter performed when the DAC is off?
Seems the DAC is inherently noisy, no matter what kind of power supply it uses.

The latter is with DAC powered ON but with "PAUSE", when de output RCA is interrupted by the relay. As you can see there are two types of noise: one from the external adapter which pollute the entire ground and another one which is from internal switching regulators and maybe digital/analog conversion. In fact you can see it(the last one) on the THD FFT like ultrasonic spikes.

On THD from adapter, there are more spikes uncorrelated with the signal. Don't look at the numbers, the difference between them is irrelevant.

 

[donald24]

omg, I ,for my part, did just swap out the PS to be on the safe side instead of a rogue PS wrecking my device. It felt a bit cheap and light, and people were complaining, about dead units. I never bought that for any audiophile-measures.

Happy listening - awesome device!

 

[kukocz]

I scrutinized those graphs and made my personal conclusion that the unit is inherently noisy, and upgrading power adapter has very marginal improvement --- It doesn't solve the jitter and noise issue. DX3Pro is a good enough product for most people, but seems the ASR forum creates a hype and overrates it. at similar price range there're a variety of other options available that gives better performance.

Could you give examples of other options available?

To be honest, I haven't seen other dac measurements showing output noise level when either dac is paused or playing zeros. It would be interesting to see the comparison with other competitors.

 

[chrisliuboy]

I've combed through this thread, and I still don't understand why there are two seemingly current (but differently numbered) versions of the driver available.

• v4.14 is the latest one with a dedicated entry on Topping's support page (dated 2018-11-20)
• v4.47 doesn't have its own entry, but it's available through a link in the entry for the latest firmware update (dated 2018-12-17)

Can anyone shed some light on this? Maybe it's been covered already and I missed it, but I did look.

If you open the link of "4.14", it's 4.47 inside..... I download the driver right after release in Nov, it's 4.47, just checked.

 

[chrisliuboy]

There's no need to measure the noise level when DAC is completely silent. You only need to see amirm's measurement for the 1khz main tone and remove 1khz and all its multples.

for instance, compare DX3 with Schiit Modi 3 (https://www.audiosciencereview.com/...-of-schiit-modi-3-dac.4742/page-2#post-104838) or Khadas tone board (https://www.audiosciencereview.com/...ents-of-wesiontek-khadas-tone-board-dac.4823/), or even SMSL Sanskrit 10th (https://www.audiosciencereview.com/...msl-sanskrit-10th-dac.5702/page-2#post-127278) . When you remove 1khz and it's harmonics, you'll see there're very little noise above -140db. Whereas DX3 has quite a lot of spikes above it.

I would say this could be the main cause for the linearity issue --- I bet when the main tone is below -100 db, the noise floor will not go down a lot like the other products, which causes a bad SNR when the audio signal is very low.

At -130db it's not an issue for humans, but I would say dx3 is more noisy than the other two products.

Of course there're a lot more DX3 could offer compare to a good $100 DAC (such as Tone board or Modi 3) w/ a good performing $100 amp (such as JDS atom), such as a nice case, a big display, a remote, and bluetooth. But if we're only focusing the audio performance, with $220 budget you could get something better. For those who get it at 11/11 promotion for $160, I would say there's nothing could beat it at this price. At regular price I believe alternatives such as a Modi3 + JDS atom might be better --- you also get good warranty support in the US if things fails.

True, I got DX3 because it's an reasonable size all-in-one unit, simple is better(for me). I don't want to end up piling up different units on my desk and different PS in the back and their design style even don't match.... I also tried the Schiit combo last year and returned, that combo always sound a bit muddy to me and you know schiit's build quality..returned quickly. So after that I always looking for some good combo, currently happy with DX3.

 

[AresHarvest]

If you open the link of "4.14", it's 4.47 inside..... I download the driver right after release in Nov, it's 4.47, just checked.

Weird. I appreciate you letting me know!

 

[777]

The noise in Topping Dx3Pro is divided in two types of noise. One is from outside power supply, aka adapter (we talked about it last time)
and the other one is from inside unit power supply. I studied internal noise yesterday and I found at the RCA output a fundamental frequency of 570khz. After that I was looking at the input power supply votage (15Vdc) with the DAC "on" and I found the same fundamental frequency in the voltage ripple. Here, at the input, the voltage ripple has 120mVp-p ! So, the first voltage regulator from inside the unit has a big charging currents at 570khz. Here is the culprit. I looked to see what regulator it is and I found TPS54331. In the datasheet we found that: TPS54331 it is a step-down DC-DC converter with 570khz switching frequency. It has at the output an LC filter. This capacitor must to be large enough (in Dx3Pro is) and very important, to have low ESR at the frequency of interest. Unfortunately Topping put an electrolytic capacitors here. Until 100khz that type of capacitors could be very good but at 570khz and upper they lose their efficacy. Probably it was better few low-ESR tantalum capacitors in parallel or ceramic high value again in parallel mode. The best would be an linear regulator but the space is too small.