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Topping DX5 DAC/headphone amplifier - Mini Review

pma

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The Topping DX5 is a desktop class DAC/headphone amplifier all-in-one device. It is delivered in a nice box with quite significant texture.

DX5_box.JPG


DX5_inbox.JPG


The front side has two headphone outputs in the form of a 4-pin XLR and 6.3 mm TRS, both for single-ended connections. In the middle is multi-functional OLED display, on the right a volume knob combined with a setup button.

DX5_frontview.JPG


The back on the right side has the power switch and the IEC AC power inlet. The digital inputs are next – USB Type-B, optical Toslink and coaxial RCA. Bluetooth antenna is a removable one. In the analog section there are singled-ended RCA line outputs, as well as balanced XLR outputs to use the device purely as a DAC or preamp.

DX5_rearview.JPG


The SMPS power supply is based on Meanwell IRM-20-15 AC/DC converter. It accepts 100V – 240V / 50 – 60Hz mains input voltage. The USB input uses the XMOS XU216 USB controller. Bluetooth connectivity comes in the form of a Qualcomm QCC5125 circuit. Two ESS Sabre ES9068AS 32-bit 2-channel DACs are used. Headphone amplification is NFCA based on TI TPA6120.

Block diagram is as follows:

Blockdia_s.jpg



Controls & Operation

The device has dedicated DAC, PRE, and AMP modes that are chosen by a remote control or by a multi-functional volume/setup knob.

Operational modes:

DX5_opmodes.jpg



Parameters

Specifications.png


Measurements

Complex set of measurements has already been provided by @amirm

I have measured the DX5 with E1DA Cosmos ADC and the result is affected by E1DA intrinsic noise at its 4.5V input range. Below the THD and THD+N at 1kHz.

DX5+Cosmos_1k.png


I am also attaching RightMark RMAA test report as a pdf, please note that RMAA test is performed at -3dBFS.

Filters and impulse responses

The DX5 has 3 settings of digital filters:

- linear phase fast No.1
- minimum phase slow No.2
- minimum phase fast No.3

I am attaching frequency responses and also impulse responses.

DX5_hires_44.1k_Filtr1-3.png


Impulse_Filtr1.png

Filter 1

Impulse_Filtr2.png

Filter 2

Impulse_Filtr3.png

Filter 3

The DX5 spectrum is perfectly clean even in the ultrasound range (measured to 10MHz)

Filtr3_10Meg.png

Filter 3, white noise, extended measuring range

Sound and conclusion

I tested the DX5 in the PRE mode connected to my PMA-NC252MP power amplifier, through its XLR balanced output. There is no sign of noise, the sound is clean, clear, with very good resolution, soundstage and transparent from low to high frequencies. Current DACs have achieved top parameters, with almost no space for improvements.
 

Attachments

  • RightMark Audio Analyzer test_Topping DX5.pdf
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pma

pma

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Some more measurements

I confirm the Toslink jitter level that @amirm has measured here

I measured this
DX5_jitter_toslink.png


I cannot confirm the IMD hump, measured by @amirm

My sample is free of IMD hump, maybe for the reason of different firmware compared to the 2022 reviewed sample?
DX5 DIN IMD vs. output.png

(Note: with Topping D10s I measure IMD hump as well)

THD vs. level goes linear as well
DX5 THD vs. output at 1kHz.png
 
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pma

pma

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Some members have complained about pops or clicks from the DX5. There is a common problem when connecting any DAC with internal PSU and class I design when connected to power amplifier that is also in class I, both devices having the signal ground connected to protective earth, PE. I have many reports from other users who have had such configuration. I tested it yesterday with m DX5. In case I use DX5 with my NC252MP connected through balanced XLR line, everything is OK and there are no pops or clicks under any conditions. But, If I connected the DX5 with the class I power amplifier via RCA single ended cable, there are clicks audible from speakers when switching the DX5 input or switching between tracks (though there is no hum/buzz from speakers). This happens due to interfering currents through the signal ground wire of the RCA single-ended link, due to ground loop between the 2 class I devices. It would be nice if @amirm tested the RCA link immunity if the DUT is connected to grounded class I input of the AP.

So do not use this:

DAC class I RCA.png



But use this!

DAC class I XLR.png



Balanced differential input subtracts the interfering click voltages.
 

lantsem

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Hi. Could you do another test with dithering setting set to "high" value for "lowest distortion"? It's an option added via firmware update "to optimize IMD performance indicators" after ESS IMD Hump was detected by reviews. l7audiolab remeasured IMD performance with all three values of dithering, but it remains unclear how the option values affect overall performance.

My sample is free of IMD hump, maybe for the reason of different firmware compared to the 2022 reviewed sample?
Hmm. Or maybe dithering option is already set to "high" value on your DX5?
 
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