QLS Audio, HI-FI/HI-END Audio,DAC,WAV Player




QA350 MOD V2+ --SD Card WAV High Fidelity Music Player

QA350 MOD V2--SD Card WAV High Fidelity Music Player

 This Discontinued Products


QA350 MOD V2+ is an all-in-one portable SD card HiFi wav music player. It has a high quality DAC and headphone amplifier integrated into its tiny body. The headphone output is able to drive most 16-300Ω headphone in the market.

It is upgraded from QA350 with huge improvements regardless of the balance of frequency and timbre, resolutions, accuracy, low and high frequency extension and dynamic range.

QA350 MOD V2+ upgrades the headphone amplifierfrom MAX9722A to AD8397 by taking advantage of AD8397’s Rail-to-Rail and high output current technology. In order to push the performance of QA350 platform to the maximum potential, the engineering team put a lot of efforts in optimizing power supply systems and PCB, and more than 10 versions of PCB were tested to get the final PCB design.

QA350 MOD V2+ employs 7.4V Li-polymer battery normally used on aircraft models. This type of battery has very low internal resistance and high discharge rate. The momentary discharge current is able to reach couple of amperes easily. This gave QLS design team the opportunity to get rid of the voltage boost circuits and voltage reversal circuits that are very common to see in the portable players. Therefore QA350 is able topresent the music with enhanced bass and transient response, as well as ultra-low high-frequency noise and full of details.

The good thing kept on QA350 is the single threaded real time audio play program with SD card. This unique technology is QLS’s guarantee to be HiFi. It is without any interrupt to steam the music files, other control functions are carried by another separated microprocessor. It achieved extremely high accuracy on the time sequence when streaming music files from the SD card. Moreover a special customized 11.2896 2ppm TCXO with jitter lower than 10PS is used as the main sampling clock.Thus the whole system reached our goal on the recovery of musics.


  • Support format: 16bit 44.1K WAV (the same with CD ripping and file format).
  • SD/SDHC up to 32GB with FAT32, 90 folders up to 900 music tracks
    (Please use TOSHIBA original card, other brands of sd card may be a problem.)
  • Firmware upgradeable
  • Digital output chip: CS8406.
    DAC Chip: Wolfson WM8740.
    LVP: AD8656.
    Headphone Amp chip: AD8397.
  • Output:
    - Digital Coaxial RCA
    - Digital Optical(round)
    - Analog Line out: 2V (RMS), frequency response 20Hz-20KHz, SNR> 100dB, Distortion <0.002%
    Headphone out: 500mW/16Ω;   250mW/32Ω;   49mW/300Ω;  Frequency response: 20 Hz-20Khz;
    THD + N (total harmonic distortion plus noise): <0.003%, matching impedance: 16 ohm --- 300 ohm
  • Battery Type: 7.4V Li-Po battery of Model General Specifications, maximum size: 55mm * 31mm * 16mm; the capacity is usually among 800-1100mAH.
  • Battery life: 4 to 6 hours.
  • Charging time: 1.5-3 hours (when charging, playing music can available powered by the external power supply)
  • Charger: 110-240VAC, 800mA/S, balanced 2 cell charger.
  • Power: 150-180mA (LED backlight OFF), 200-300mA (LED backlight ON), 9VDC external input.
  • Remote control
  • Dimension: 135mm * 78mm * 27mm (excluding the output socket, switch, button, etc.)
    150mm * 78mm * 30mm (with all the sockets, VR button, switch, button)
  • Package size: 235mm * 135mm * 55mm
  • Single Weight (with battery): 0.3kg
    Packing Weight: 0.75kg

About WAVs...

WAV files are the favourite format choice of people who can't bear the sonic difficiencies of the lossy compressed MP3 format yet want to store, preserve and playback treasured CD collections from their computer hard disk drives.

Up until now, these people would simply be content to use their computer as their main Hi-Fi source component.

Whilst excellent at converting CDs to WAV files, the PC / Mac is still not the ideal music plackback device. The majority if PCs don't have the best powersupplies and are absolutly packed with noisy, interference inducing components. Multiple noisy fans buzz away constantly and due to components fighting over limited resources, "pops" and stutters on the audio are not uncommon.

In these days of hugely expensive utility bills, the electricity consumed in putting a computer to use for considerable periods just for music playback is also quite considerable as is wear and tear to the hardisks.

Reasons why the QA-350 is a better music transport than a PC...

  • Silent (no moving parts)
  • No pops stutters or audio glitches (assuming that WAVs were extracted with love by EAC)
  • Uses nowhere near the amount of energy that a PC needs
  • Far more compact than even the smallest laptop PC
  • Useful remote control functionality
QA350 MOD V2--SD Card WAV High Fidelity Music Player

QA350 MOD V2--SD Card WAV High Fidelity Music Player
QA350 MOD V2--SD Card WAV High Fidelity Music Player
QA350 MOD V2--SD Card WAV High Fidelity Music Player

QA350 MOD V2--SD Card WAV High Fidelity Music Player

Internal PCB board:
(In order to improve the quality and sound quality, components are subject to change without notice.)

QA350 MOD V2+ Player Internal PCB board

QA350 MOD V2+ Player Internal PCB board

If you are an electronics&HiFi enthusiasts, and if you need this product's circuit schematics by PDF file, please contact to Clark: cxqmcu@cxqmcu.com for get  , (Please make sure that the files can not be used for commercial purposes, and also can not be share in network, and you are already has this product or will buy it.)


The following items are included with your Order:
  QA350 MOD V2+ Player*1 (Inside is include a 7.4V Li-Po battery)
  Remote Control * 1
  Toshiba 16G SD Card * 1  
                                   (Please use TOSHIBA original SD card, other brands of sd card may be a problem.)
SDHC SD USB 2.0 Memory Card Reader *1 (Card Reader not Warranty)
  Wall Mount DC Power Supply *1
(Input: AC 110V-120V or 220V-240V , Output: DC 9V or DC 12V )
  Balance charger * 1
  3pin changing cable *1

User Guide x 1

This is Discontinued Products

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Your personal account manager is:
Clark chen - cxqmcu@cxqmcu.com    clark_chen@aliyun.com    315392961@qq.com

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E-Mail: cxqmcu@cxqmcu.com