Internal design and architecture fo the iBasso DX80 DAP
As briefly introduced in 1st part of the review, the Ibasso DX80 DAP MP3 player entails a new platform design. It moves to a newer lower power quad-core chipset based on the Cortex A7 with a frequency of up to 1.3GHz that includes, among others, integrated S/PDIF output used in the coaxial/optical jack at the top of the DX80 (see below).
Fig.1: Top view of the Ibasso DX80 mainboard.
- Each side of the Mainboard has one microSD connector for a total of two in the Ibasso DX80 DAP.
- New Cortex A7 based processor helps improving the playback battery life with a minimum of 12/13hrs depending on the load and volume.
- It keeps using 512MB Ram which should be plenty for a dedicated music player that doesn’t need multitasking or gaming.
- At the bottom of the player, we can see the 6 Nichichon Golden series “reservoir” capacitors that make sure the output audio stage never runs “dry” of current.
- On the top view, we have the DUAL DAC CS4398 that is shielded separately from the digital section (other players with this configuration such as the A&K 120 II, cost as much as 3 times the Ibasso DX80 DAP).
- One of the big novelties on the Ibasso DX80 is the addition of the USB XMOS receiver that supports up to 32bits/384KHz in PCM mode and native DSD( DSD64 (2.8MHz), DSD128 (5.6MHz), DSD256 (11.3MHz), DSD512 (22.6MHz)). In order to find a portable music player with such capability you need to jump up to an Astell&Kern AK240 (at 2500 USD, you can buy 6 or more DX80…).
- Output stage is designed around dual supply IC that generates around +/-5.1V (with the help of an extra pair of Nichichon GOLD SERIES capacitors) for the dual OPA1602 as voltage gain and dual LMH/BUF current buffer output.
- It keeps the output relay from the DX50/90 family to block any “pops” at start or shutdown of the player.
Fig.2: Bottom view of the Ibasso DX80 mainboard
Comparative Ibasso DX80 DAP
|SoC CPU||Quad-Core ARM Cortex-A7
|Single-Core ARM Cortex-A9
|Dual-Core ARM Cortex-A9
|RAM memory||4 Gb 16 bits DDR3 SDRAM||4 Gb 8 bits DDR3 SDRAM||4 Gb 16 bits DDR3 SDRAM|
|FLASH memory||Samsung 8GB (fully enabled for the OS)||SK Hynix 8GB MLC NAND||Micron 8 GB MLC NAND|
|Battery and SoC Power Management IC||Richtek RT5037||X-Power APX202||X-Power APX202|
|USB controller||XMOS XS1-L6A supports PCM up to 32/384KHz and DSD64/128/512||Integrated inside Rockchip RK2926 limited to PCM 24/192KHz and no DSD||Integrated inside Rockchip RK2926 limited to PCM 24/192KHz and no DSD|
|S/PDIF output||Integrated in Rockchip RK3128 using Coaxial and Optical combo jack.||Cirrus Logic CS8406||Cirrus Logic CS8406|
|DAC||Dual CS4398||Wolfson WM8740||Dual ESS Sabre32 ES9018K2M|
|High Pass Filter + Voltage Gain stage||“SoundPlus” OPA1602||OPA1611||OPA1611|
|Output Buffer||Dual LMH65 or BUF634||None||BUF634|
|Output relay||NEC UD2||NEC UD2||NEC UD2|
Line out measurements
|Line Out||10 KOhm|
|Dynamic Range||112.34 dB|
|Crosstalk (L)||-86.9 dB|
|Crosstalk (R)||-86.2 dB|
|Output Voltage||1.566 Vrms@0.022%|
(20Hz – 20kHz)
|Floor noise||-102.93 dBu|
|CCIF IMD (max)||0.0014%|
Fig.4: Summary of the iBasso DX80 DAP Line Out measurements
Fig.5: Frequency Response of the iBasso DX80 DAP
Fig.6: DAC linearity and floor noise of the iBasso DX80 DAP
Fig.7: Output voltage of the iBasso DX80 DAP
Fig.8: THD+N of the iBasso DX80 DAP
Fig.9: Dynamic range of the Ibasso DX80
Fig.10: Crosstalk of the Ibasso DX80
Fig.11: Intermodulation SMPTE of the Ibasso DX80
Fig.12: Intermodulation CCIFof the Ibasso DX80
Overall, the Line out function performs decently as a good analog source for an external amplifier, with very low noise output (below what the human can hear), lower distortion (particularly at high frequencies) and improved both CCIF and SMPTE intermodulation compared to the jack output. The Ibasso DX80 DAP is as pure as source as a dedicated ODAC RevB
Time analysis Ibasso DX80 DAP
Fig.13: 30Hz Square wave of the Ibasso DX80
Fig.14: 300Hz Square wave of the Ibasso DX80
Coaxial output measurements
After purchasing a TOSLINK to 3.5mm jack adaptor, we have been able to hook our Ibasso DX80 DAP to the optical input of the AP585. You could use a coaxial cable to carry the S/PDIF signal too, but TOSLINK unlike coaxial cables, are immune to ground loops and RF interference. TOSLINK cables may suffer permanent damage if tightly bent, you need to be more careful.
The measurements look as neat as you can imagine from a pure digital signal in an optical format. In the digital world, there are no Volts or Watts, the digital signal goes from -1V to 1V and is measured in dBFS, being +0 dBFS the maximum output of a digital system.
Fig.16: Maximum digital S/PDIF output of the Ibasso DX80
Fig.17: Zero distortion for the Ibasso DX80 on its S/PDIF optical output
Fig.18: IBasso DX80 floor noise at -180dBFs (!!) in the Optical S/PDIF output
This second review emphasizes on the inner design of the Ibasso DX80 and how it focuses on the sound quality through a very careful audio section coupled with high quality components.
As well, we measured the fixed Line Output that achieves lower floor noise and slightly less distortion THD+N than the analog jack, so it highly recommended when you want to use an external amplifier or for an active set of speakers.
Finally, we looked at some measurements on the optical S/PDIF output and highlighted how clean it is. Definitely, the best option if you want to connect the Ibasso DX80 DAP to a superior DAC or AV system at home.