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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

JohnYang1997

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UPDATE:
Two channel driven with 8 Ohm, same result. Same distortion figure 0.001x% for both channel. I haven't tried high gain to see the full potential of this amp stage. But it's already 450mW at 8 ohm.

Now it's very likely the limitations isn't the current output of this output stage but the power supply, either the external power supply or the internal regulator. I may need some calculation.

No it doesn't make sense. The efficiency should be much worse with 8ohm load. 450mw is not far from 570mw on number. I should have been drawing more power than amir. Still I am going to try high gain with 8 ohm and 36ohm/or 32ohm real headphone.
 

JohnYang1997

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Ok. Some configuration was done wrong. Retested with high gain. Highest without clip -8.5db which is essentially 0.5db more than low gain max volume. Distortion is 0.006% which is higher than at low gain which is understandable.
Max power is 550mW. 8ohm load. Rough calculation.
So it may be the power limitation of the power supply.
So what it means, it can drive lower impedance load just as good. It's neither the voltage nor the current the caps the output power but the power delivery. Making it one of the best amp for 8 ohm headphones.

Update: it's also unlikely to be the external power supply. It could be the current is the limit tho. I just ran high gain with single channel it's the same clipping level as two channel driven.
 
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JohnYang1997

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Analysis:
As calculated the maximum output current with 32ohm is about 150mW which is considerably lower than that with 8ohm. Also the maximum output doesn't change whether it's single channel driven or both channel driven.
Conclusions so far. The current output capacity is much higher than we expected or we saw according to amir's data. Then I managed to get higher power with 32ohm than amir but considerably lower current than with 8 ohm. This indicates power delivery limit. However it doesn't change whether it's both channel driven or not. So external power supply won't make a difference. It's not the total power that's lacking.
Question remained: two channels basically behaves independently. I don't know if the supply rails are splitted for each channel. If that's the case that may be the regulator that hits its power limited. If shared supply, I have no idea.
Takeaway: At least my unit is more powerful at 32ohm and at 8ohm it can still output 500mW+ dual channel driven.
 
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Thanks for your hint and lead me to check for DX3Pro diagramatic, Coaxial and SPDIF input passing through AK 4118 which support 24-192kHz before AK 4493 . Let me think how to link Aries Mini USB DAC to DX3 Pro USB input.

Edit: There's USB DAC at Mini for USB connection, will give it a try on pure AK 4493 DAC 's sound generated.

View attachment 29222
Tested with DSD files with USB DAC into DX3 Pro just now, everything is fine now , nevertheless there's smallhiccup… forgot to change DSD Native to DSD DoP, loud hissing sound from speaker , oops luckily my test was in low volume.
 
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While I'm waiting for my DX3 to arrive, can anyone answer this question?:

Once it's connected over USB, does/can the Windows volume control do anything? I ask because my keyboard has volume control keys that trigger the native Windows functionality and I'd love to keep using it, big clicky DX3 knob or not.
I believe you can control the volume at both Window and DX3 unit. Try it later since you have purchased it :p
 
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Not on ASIO with "no volume" RCA output. I have to use the volume on the receiver. No software volume on window , player software or DX3
My bad, I am not using ASIO or WASAPI, but using Aries Mini, can control volume from their Lightning DS apps and Roon apps. I can control the volume (dB) on DX3 Pro at DAC Pre-Amp, headphone mode. Usually I fix the volume (-30dB) at DX3 Pro and using integrated amplifier remote control to control the sound volume , need to crank up volume a lot though.
 

KarikBR

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I have a speaker that can connect via RCA OR 3.5mm jack (Logitech Z323 ). The 3.5mm jack is the normal mode that I use to connect it to my notebook, in the headphone output. Can I connect this speaker (it is powered with directly in the wall socket) by using the headphone out 3.5mm of the topping DX3 pro ?
 

JohnYang1997

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I have a speaker that can connect via RCA OR 3.5mm jack (Logitech Z323 ). The 3.5mm jack is the normal mode that I use to connect it to my notebook, in the headphone output. Can I connect this speaker (it is powered with directly in the wall socket) by using the headphone out 3.5mm of the topping DX3 pro ?
Either.
 

Music1969

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Can anyone kindly confirm the current output of the stock included AC-to-15Vdc power adapter?

And is it a 5.5 x 2.1 mm DC plug?

It doesn't come with a plug for my country and I don't want to use an international AC adapter, so will source a good SMPS.

Probably a Mean Well or IdealPower UK.
 

JohnYang1997

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Can anyone kindly confirm the current output of the stock included AC-to-15Vdc power adapter?

And is it a 5.5 x 2.1 mm DC plug?

It doesn't come with a plug for my country and I don't want to use an international AC adapter, so will source a good SMPS.

Probably a Mean Well or IdealPower UK.
The stock external power supply is good enough proven by single channel driven has same output of both channel driven.
And about the spec, 1A 15Vdc inner positive 2.1mm plug. You can pickup whatever that has the same polarity+same voltage+not less current.
 

Music1969

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The stock external power supply is good enough proven by single channel driven has same output of both channel driven.
Noted and thanks for the info. This isn't the reason I'm looking for another SMPS.

As above, it doesn't come with a plug for my country and I don't want to use an international AC adapter.
 

Music1969

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I haven't done testing but I'm pretty confident that it is.
Noted. Hopefully amir can confirm.

Do you know what the AKM AK4493EQ chip in the DX3 Pro internally oversamples PCM up to?

To 768 kHz? or to ~1.5 MHz like some ESS chips.

Only asking out of general interest.
 
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