The Questyle Audio CMA800R 

Current Mode Headphone Amplifier 

The quest is endless.  The Questyle Audio CMA800R, the flagship "Current Mode" Headphone Amplifier from Questyle Audio, is a dedicated quest for perfect sound.




Questyle Audio’s outstanding "Current Mode Amplification"  technology (subject to a PCT patent held by and the core technology designed and developed by, Questyle Audio CEO and founder Wang Fengshuo) provides the airiness and musicality of a tube amp while maintaining the speed and accuracy of transistors. 




“I heard details previously buried deep in the track. The sound was dynamic, ethereal, detailed and precise with no unpleasant artifacts of any kind.Everything you want music to be was there.”

                                

                                  





What is Current Mode Amplification?

In current mode amplification, the signal is amplified by modulating current instead of Voltage. It is widely applied in the high speed communication industry and the video processing industry, but it is Questyle Audio’s patented technology as applied to headphone amplifiers.

Learn More about Current Mode Amplifier>>


Why We Choose Current Mode Amplification?

Low distortion and wide bandwidth are the goals of all high performance amplifiers. Only with ultra wide bandwidth and high speed processing can an amplifier wonderfully process sudden pulse wave signals, and achieve realistic playback of music signal with speed and transparency.

 

To achieve this Questyle Audio abandoned the traditional voltage mode format and developed “Current Mode” amplification. When the component is working in Current mode, the amplifier Slew Rate (SR) achieves a linear increase as input signal amplitude increases, in direct proportion to the input signal amplitude. When receiving a high amplitude signal, a “Current Mode” amplifier’s SR is much faster than traditional Voltage mode devices, totally eliminating TIMD and ensuring a high amplitude signal with an extremely wide linear bandwidth and an almost distortion free realistic playback. 



Work Principle

To maximize accuracy, current capability, and consistency, Questyle Audio’s Current Mode Amplifier employs all discrete componentry, in a Class A configuration. To insure maximum compatibility with source units and speakers (headphones), Input and Output both work in voltage mode. From the diagram we can see, input signal will travel first to VCCS, voltage mode is converted to current mode here, then it goes to Ai for amplification (in current mode), next it goes to I/V converter to become voltage mode again, and then is output to OPT stage to drive headphones. 




An Excellent Headphone Amplifier with Outstanding Performance Specifications

Ultra-low distortion





Hi-End Components


Chassis

10mm Thick Aluminum Cover and Bottom Chassis

The Questyle Audio CMA800R’s aluminum chassis is produced by Foxconn using precise CNC tooling machines. The upper cover and bottom chassis “mutual bit” structural design, provides the Questyle Audio CMA800R with stable heat, excellent control of sympathetic vibration and excellent shielding from RFI/EMI radiation.


Mono Full Balanced Function  

The Questyle Audio CMA800R is the world first headphone amplifier to offer Mono Full Balanced output. To create a proper balanced output, a stereo amp is required for each channel. Rather than compromise by using a transformer or resistors, Questyle takes advantage of this by allowing you to switch two Questyle Audio CMA800Rs into “Mono” mode, putting each one into a “Mono Full Balanced” configuration, effectively bridging them in a “Duel Mono” set up. The output power is four times that of a single Questyle Audio CMA800R, separately driving the left and right channels, with an ultra-low 0.00038% distortion, and unparalleled channel separation, able to drive high impedance and low sensitivity headphones deeply, improving resolution and dynamics. In this Dual Mono configuration, each channel’s power supply and amplification are independent, providing first class driving power, which is especially outstanding in driving difficult to drive headphones or headphones which lack in sound field or separation.

“The Questyle CMA800R, while not cheap, is already an excellent amp when used alone. Adding another turns it into a world class powerhouse that can challenge most anything on the market. “

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The Sound of the Questyle CMA800R with Sennheiser HD800

“The sound from the Questyle CMA800R in combination with the HD800 is quite simply spectacular. Paired with the CMA800r it is smooth in the extreme but the bass is what comes to the fore with this pairing. It is fast, tight but also extends very well indeed. As a headphone amp the tonality matching with the HD800 is almost perfect and for other headphones it plays to obvious strengths.”




“ The team of CAS192/CMA800R/HD800 resolves this stuff like pretty much nothing else I've experienced this side of a megabuck electrostatic setup. If detail is your thing, I can't imagine doing much better than this.”





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 “With the fully balanced dual mono Questyle system in play, I started to eat my words. The sound was simply more 'alive' for lack of a better term. The LCD-3, for the first time in my experience, sounded like it was actually worth the price increase over the LCD-2. I've always said that I enjoyed the 3 and appreciate the accomplishment Audeze has made, The sound was simply more 'alive' for lack of a better term.”


-- John Grandberg

--“Head-fi”

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Quality Control

Each product is burned in for 72 hours before shipping and every product has its own serial number and test report. The engineers prepare two copies of the test report, one report is put in the box for the customer and another report is kept in a safety deposit box at Questyle. If there are any questions, about any product, at anytime, Questyle is able to find the report, for that unit, to aid in solving any issues. For distributors, Questyle can provide a professional technical guide.


Specification 









  • Gain:  15.5dB

  • Max Output Power:  

    180mW (7.5Vrms) @300Ω, standard Stereo Mode

    710mW (15Vrms) @300Ω, Mono Mode

  • SNR: 114 dB, standard Stereo Mode

                118 dB, Mono Mode

  • THD+N:

    0.00038%@1kHz, 300Ω standard Stereo Mode

    0.00026%@1kHz, 300Ω Mono Mode


  • Frequency Response:

    DC-200kHz (+0, -0.3 dB); DC-650kHz(+0, -3 dB)

  • Sensitivity:  1.2Vrms

  • Impedance:  47KΩ 

  • Input:

    XLR stereo, RCA Stereo, and XLR Mono Full Balance input 

  • Output:

    Dual 6.35mm Stereo headphone Jacks,

    a XLR Mono Full Balance output, 

    A pair RCA Pre-amp output 


  • Work Status:Pure Class A

  • Voltage:

    100-120Vor 220-230V, Internal switchable

  • Power Consumption: 13W

  • Dimension:  330*300*55 mm