QA350--SD Card WAV High Fidelity Music Player

QA350 is a WAV high fidelity music playerdesigned and made by QLS Electronics. SD card is applied asstorage medium while lossless WAV format as the soundsource. The player integrates DAC and headphone Amplifiercircuit with the built-in high-capacity rechargeable lithiumpolymer battery. It is convenient to carry with and playmusic.

QA350 retains the optical andcoaxial digital output of QA-550, while increases the analog(LINE OUT) output (which can be directly connected to youramplifier or pre-level) and the amp output, which can drivethe majority of 16-300 headsets.
More professional components, more rigorous screeningmechanism of components, more stringent design layout, morerigorous testing and debugging are applied in QA350. Usersare allowed to fully experience an unparalleled listeningenjoyment brought about by the player.

Features:

• Use 2PPM 11.2896 TCXOCrystal (crystal JITTER is below 10PS)
• The power supply part use several LDO,respectively offer power for: crystal oscillator, themain chip, the digital output chip, DAC digital, DACanalog, headphone amplifier, display control, to ensurethe best sound quality.
• In portable system, fever gradematerials are applied: Kemet tantalum capacitors, YAGEOSMD 1% precision resistors, high precision SMD capacitorof Samsung, ELNA electrolytic capacitors, ALPSpotentiometer.
• Lithium polymer battery of generalspecifications applied in the aircraft models serves forpower supply. The benefits are:
  • Discharge in large rate and lowinternal resistance. Discharge current can reachcouples of Ampere in a blink to increase the lowfrequency and transient explosive power of portablesystem.
  • Lithium polymer batteries appliedin the aircraft models have common specificationsand are easy to buy which facilitate users toreplace batteries by themselves. (Batteries havecertain usage life. Customized size / appearancebring great inconvenience to users for thesubsequent replacement of the battery.) (Maximumsupports of 55mm * 31mm * 16mm 7.4V lithium batteryfor model aircraft are available).
  • Model aircraft batteries commonlyuse high-quality battery cells and have enough stockand market verification for long time with stableperformance and long service life.
• Provide a professional balancecharger for models for the rechargeable lithium balancecharge, which reduces the charging time, and expandslong battery life.
• Onboard short-circuits protection andover-discharge protection ensures the battery life.
• QA350 directly applies 7.4V lithiumbattery. we spent a lot of time selecting high-end chipOPA and the OPA with good performance under low voltage.The whole player has no step-up circuit and reversevoltage circuit. The sound is transparent and pure.
• LDO filter circuit strictly matchesESR to ensure minimum ripple output.
• Firmware can be upgraded, and theupgrade is simple.
• Provide external power inputinterface, and the input voltage is DC9V-DC12V. Whenexternal power is input, the internal power supply willbe automatically disconnected.
• When the internal battery ischarging, external power supply is available. (We arenot recommended to use battery offer power supply Whenthe charging internal battery, which have significantimpact on battery life).

Product specifications Indicators:

• Play format: 16bit 44.1K WAV (thesame with CD ripping and file format).
• Storage method: SD card storage mediais applied for audio playback, FAT32 format less than(equal to) 32G, SD/SDHC), SD card support hot swap.
  Support maximum 90 folders with the maximum of 900songs; the remote control can directly select the folderor directly input the track number. The operation isvery convenient.
• Digital output chip: CS8406.
• DAC Chip: Wolfson WM8740.
• LVP: AD8656.
• Headphone Amp chip: MAX9722A.
• Digital Output: Coaxial (RCA), FiberOptical (round).
• Analog Output: LINE OUT, headphoneAMP output.
• LINE OUT parameters: level 2V (RMS);frequency response 20hz-20Khz. SNR> 100dB; Distortion<0.005%.
• Headphone amp out parameters130mW/32ohm.70mW/16ohm. Frequency response: 20 Hz-20Khz.THD + N (total harmonic distortion plus noise): 0.009%.