Review and Measurements of Topping DX3Pro DAC and Headphone Amp

[Cidious]

@777 You're the one to keep an eye on in this thread. I'm planning to make some adjustments myself. I did order the long hex key haha.

sop8 to dip8 adapters on the way and the Sparkos SS3602 discrete opamp to replace the OPA1612A. I read you have some suggestions on possible mods. I thought about decoupling the opamp with some Silmics and a wima cap. But not sure yet. Let us know when you've fitgured some modification out that might be worth it.

 

[peder2tm]

)))))))))))))))))))))))))))))))))))))))))))))))))))) You joke, ok ?

Thanks. I expected the noise to be of lower frequency than 45 MHz (each square on the plot is 50 MHz, right?).
45 MHz is close to amateur radio frequencies.

 

[777]

If you look at the oscilloscope capture (not FFT) you will see a burst noise with the fundamental frequency of 32khz. Each that burst has a a cocktail of harmonics until at hundreds of Mhz. How relevant this noise is I do not know but we can eliminate it with a linear power source. The influence on the audio band is very difficult to determine because the regular FFT measurements filter that burst noise. In real life everything will depend on how the amplifier is built, what will that noise make. I repeat, it's not about regular audio systems, I'm talking about hardcore audiophiles.
Topping Dx3Pro is one of the best DAC in his class and beyound this.

 

[Veri]

If you look at the oscilloscope capture (not FFT) you will see a burst noise with the fundamental frequency of 32khz. Each that burst has a a cocktail of harmonics until at hundreds of Mhz. How relevant this noise is I do not know but we can eliminate it with a linear power source. The influence on the audio band is very difficult to determine because the regular FFT measurements filter that burst noise. In real life everything will depend on how the amplifier is built, what will that noise make. I repeat, it's not about regular audio systems, I'm talking about hardcore audiophiles.
Topping Dx3Pro is one of the best DAC in his class and beyound this.

Nice to hear

 

[noel_fs]

I reported the 54331 noise issue and linearity problem to topping. Let's see what they can do.

nothing

 

[amirm]

I tested the DX3 Pro broadband spectrum with its own power supply and that of the lab.

Own supply:

Lab supply:

There is almost no difference until 100 kHz. Even after that there is not much of substance. The noise spikes are internally generated or passed through from USB. Either way they are well above frequencies of interest.

 

[amirm]

Thanks @amirm, what about linearity using spdif/toslink? That's useful in isolating the cause (whether it's a usb only [driver/firmware] problem)

Here you go:

It is better with the other two interfaces but still not as perfect as their other products.

 

[yue]

Here you go:
It is better with the other two interfaces but still not as perfect as their other products.

Thanks a lot! This is very interesting indeed.
Coaxial and toslink results also differs, but they actually go through the same chip.
perhaps this is a grounding noise issue?
I still believe there's something wrong is going on in the USB digital processing (either firmware or driver) though.

 

[amirm]

It might be. How it is grounded changes USB measurements.....

 

[Tatteredmidnight]

Thanks a lot! This is very interesting indeed.
Coaxial and toslink results also differs, but they actually go through the same chip.
perhaps this is a grounding noise issue?
I still believe there's something wrong is going on in the USB digital processing (either firmware or driver) though.

They seem to overlay each other quite well. Channel 1 on both fall, while channel 2 rises. Toslink is slightly more jagged, but nothing substantial.

 

[pejakovic1]

It is a product of sufficient quality.

It is 1.66A, will it be a problem?

 

[Stein]

amirm's post at https://www.audiosciencereview.com/...c-and-headphone-amp.4967/page-100#post-140656 already proved the original power supply is good enough.

Actually, for units that suffer from random shutdowns or can't exit standby mode, this is what Topping suggests:

 

[yue]

Actually, for units that suffer from random shutdowns or can't exit standby mode, this is what Topping suggests:View attachment 20519

Ok then 1.66A is definitely sufficient. Anything> 1A should work fine.

 

[la2ygoo]

I tested the DX3 Pro broadband spectrum with its own power supply and that of the lab.

Own supply:

View attachment 20511

Lab supply:
View attachment 20512

There is almost no difference until 100 kHz. Even after that there is not much of substance. The noise spikes are internally generated or passed through from USB. Either way they are well above frequencies of interest.

There is a lot of noise in the range that can not heard.

This test should be run when measuring new equipment.

 

[yue]

There is a lot of noise in the range that can not heard.

This test should be run when measuring new equipment.

agree! @amirm

 

[pejakovic1]

amirm's post at https://www.audiosciencereview.com/...c-and-headphone-amp.4967/page-100#post-140656 already proved the original power supply is good enough.

I'm taking it to see if the buzz in speakers will be fixed, notice i said buzz, not hiss. So is 1.66A, 15V safe?

 

[yue]

I'm taking it to see if the buzz in speakers will be fixed, notice i said buzz, not hiss. So is 1.66A, 15V safe?

I don't think that can fix it. buzz/hiss are usually created by ground loops. It's very unlikely to be sourced from power noise (as usually switching power noise is usually either 60hz multiples or high frequency).

 

[yue]

It might be. How it is grounded changes USB measurements.....

are you using the stock usb cable provided from the manufacturer? Will a cable with ferrite chokes improve the situation?

 

[777]

Better USB isolator. That break the groundloops.

 

[SiW]

@amirm to make sure we are talking about the same power supplies from Topping can you post a picture of the one supplied with you unit?