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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

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Was this Zeos review? Its so easy to change between headphone and pre-out, its one button on the remote for headphone out, and one button for pre-out, you press the pre-out button again and it goes to line-out. Zeos issue was that people could accidentally press the line-out button twice and go to full line-out with loud volumes playing. I've done it twice myself, but I don't do that anymore as you learn pretty quickly not to double press it!!, I don't think its a big issue. Perhaps what would have been an interesting feature was if they had put sperate volume channels for line out and headphone out, so that when you change between the two the DX3 remember different volumes for either output.
Yes it was his review, thanks for the clarification.
 
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So here my final testing : Energy 5.1 tower speakers + Harman /Kardon 80rms amp https://www.amazon.com/Harman-Kardon-Stereo-Receiver-Theater/dp/B01CKDDGQO . The DAC direct output with no sound volume is awesome. With Volume On , it degrades. Easy to switch input and output's settings with remote. Less image than my older asus essence sound card but cleaner definition. It can serve as a great pre-amp with software volume, Good, clear and rather powerful headphone amp, even with DAC volume ON ( as to be) . So Yes, if you can wait for a deal on amazon, get the $$ ready . My older asus esence stx with muse opamp = 8/10 ........................, DX3 pro = 7.5/10 +
 
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Hi, I encounter certain high resolution files formats of DSD64, DSD 128, FLAC 24-bit 352.8kHz play with no sound (blinking coaxial text) in DX3 Pro in all modes (headphone, DAC, Pre-Amp) . Digital source is fed from Aries Mini.

I have tried to reset the unit by turning volume knob few times , but problem persists. Please advise what's wrong.
 

amirm

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Which part makes you think DSD is converted to PCM?
It goes into the same subsystem as PCM. So it reasons that it converts to PCM there, changes volume and outputs as PCM.
 
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Hi, I encounter certain high resolution files formats of DSD64, DSD 128, FLAC 24-bit 352.8kHz play with no sound (blinking coaxial text) in DX3 Pro in all modes (headphone, DAC, Pre-Amp) . Digital source is fed from Aries Mini.

I have tried to reset the unit by turning volume knob few times , but problem persists. Please advise what's wrong.
Test with USB input and report is you can. The headphone output is tied to the volume. Open it and inspect. It's a Chinese toy. Mine is fine. I like it. The "no Volume direct line output " sound great even with a lack of opened up sound stage. Can't have everything for $100.
 
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amirm

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Well, it contradicts with amir's test with 33ohm. This thing outputs more than 230ma right now. Idk why it clips that early with 33ohm load in amir's measurements.
Are you driving one channel or two?
 
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Test with USB input and report is you can. The headphone output is tied to the volume. Open it and inspect. It's a Chinese toy. Mine is fine. I like it. The "no Volume direct line output " sound great even with a lack of opened up sound stage. Can't have everything for $100.
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.

DX3Pro Schematic.jpg
 
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It goes into the same subsystem as PCM. So it reasons that it converts to PCM there, changes volume and outputs as PCM.
Noted but without knowing what this sub-system is doing, it’s hard to say everything is output as PCM?

This may be the “black box” that has been discussed with ESS Sabre chips for years. AKM chips may be similar.

One theory I’ve seen with ESS Sabre chips is that 1 bit SDM is converted to 5 or 6 bit SDM for digital volume control... not converted to PCM....
 
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amirm

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Noted but without knowing what this sub-system is doing, it’s hard to say everything is output as PCM?
Well, when no-DSD-volume flag is set, this whole subsystem is bypassed meaning it is not needed for DSD playback. So it reasons that the other path is for PCM and DSD to PCM conversion.
 
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Well, when no-DSD-volume flag is set, this whole subsystem is bypassed meaning it is not needed for DSD playback.
Noted, here you have direct DSD (1 bit SDM) conversion to analogue.

So it reasons that the other path is for PCM and DSD to PCM conversion.
This is the jump I’m unsure about.

As per my ESS Sabre “black box” example above, while DSD is no longer strictly DSD (1 bit SDM) with digital volume control with the Sabre chip, the long standing theory/guess is it is not converted to PCM either.

I shared a link to interesting old discussion on CA Forum a page back which goes into this.

I don’t think we’ll know unless someone from AKM can confirm.

https://audiophilestyle.com/forums/topic/19381-ess-sabre-and-dsd-volume-control/
 
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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.
 

JohnYang1997

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One thing is that even though the current output is very high the total output power is quite low. If it's limited by power supply, then it makes all the sense. I'll try to drive both channel and test with 33 ohm load.
 

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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