Munich HIGH END Show Report 2017
It is no secret i personally did the world premiere review of the QP1R (link here) and at HIGH END 2017 in Munich they announced the QP2R as the next generation of their portable music player. Furthermore, Questyle's new CMA400i DAC with headphone amplifier was also showcased. Their QP2R second generation battery powered portable music player features patented fully discrete / full balanced/ Current Mode amplification. In fact there's a 2.5mm balanced headphone jack plus the typical stereo 3.5mm jack as well. The amplification is pure Class A biased and the QP2R supports PCM384 and true DSD256.
A newly-designed "Man-Machine" interface brings further ease of use to the QP2R over the QP1R. QP2R inherits Qustyle's new design of Current Mode Amplifier built with all discrete circuit and pure Class A working state. Due to the full-balanced output, the amplifier circuits are upgraded to four groups from the original two. Four groups of Current Mode Amplifier circuits are located on both front and back of the PCB, which significantly shortens the distance that signals bypass on the PCB. Thus the audio performance is improved, which gives QP2R 0.0005% ultra-low distortion and less than 0.1Ω output impedance.
For the operating system, QP2R still uses Linux, which Questyle feels has inherent advantages on performance and stability over Android. Instead of a touchscreen, buttons and scrolling wheel make operation easy. The curvilinear machining of Gorilla Glass for the front and rear panels of the player is extraordinarily demanding on CNC processing. There's a USB Type C port for charging and data transfer, which is faster than USB 1 or 2 as found in other models in the marketplace.
Questyle has produced for them a customized 3100mAh 3.7V Li-Polymer battery that will provide over 10 hours battery life. There's 64GB internal memory and you can use a 200GB microSD card for external expansion. DAC chip is the AKM AK4490, amplification output level is 1.6 Vrms unbalanced and 3.2 Vrms balanced. Body material is CNC machined aluminum and available in Gold/Space Gray.
Questyle's CMA400i DAC with headphone amplifier inherits state-of-the-art technology of their Golden Reference System, which Enjoy the Music.com's Dave Hanson reviewed here. CMA400i can be placed straight with a specially designed stand, which is not only space saving but also eye-catching for its statue-like structure under light. Lasered dots of volume scale, which is the DNA of Questyle product family, show the accuracy and specialty of operation. Questyle's CMA400i is built with four groups of pure Class A Current Mode amplifiers and all discrete circuit, which achieves the ultra-low distortion level of 0.0006% and ultra-wide bandwidth up to DC-600kHz (+0/-3dB).
The CMA400i can drive headphones in full balanced mode as it features four groups of pure Class A Current Mode amplification circuits, and supports a 4PIN balanced XLR output, a 2.5mm balanced headphone jack and a 6.35mm standard headphone jack. In addition, the new design of Gain Control switch at the bottom of the chassis benefits CMA400i with perfect driving power for different headphones. This unit is designed with Questyle's patented True DSD technology and AKM AK4490 DAC chip.
Since we all know the power supply of a high-end audio product plays a vital role, Questyle choose to develop a customized Noratel toroidal transformer. Furthermore, to control resonances the chassis is made of aircraft-grade Aluminum 6063 and manufactured by Foxconn. The 'mutual-bit' structure and 10mm thick chassis with the CNC-tooled aluminum feet help to reduce the natural resonance to the lowest level and make CMA400i strong and stable as well.
Each CMA400i is tested by QC engineers from Foxconn with Audio Precision AP2722 before shipping and has its testing report filled. Every testing report is unique and written in two copies, one is put in the product packing box for the customer, another is kept in a safety box at Questyle to aid in following up and maintaining.
Another distinctive feature of CMA400i is switching between Headphone Amplifier and Preamplifier by using the Function switch on the front panel. In DAC mode, CMA400i supports RCA and XLR pre-amp outputs which can be selected by the ADJ/FIX switch on the rear panel. When FIX is selected, music is output at a fixed level to ensure minimal signal loss. When ADJ is selected, CMA400i drives active speakers directly and volume is adjusted through CMA400i conveniently. Max output power is 106mW @ 300 Ohms / 980mW @ 32 Ohms via normal headphone jack, and 418mW @ 300 Ohms / 3920mW @ 32 Ohms via the balanced headphone jack.