(Global PCT No.: PCT/CN2014/075775)
Current Mode Amplification, means the amplification is processed in Current
version, instead of Voltage version.
Current Mode Amplification, same as Voltage mode, also take transistors as ampli-
fication components. But the amplification circuit loop is totally different from that in
voltage mode, in the whole closed-loop all the capacitors in between those transis-
tors which affects speed and bandwidth are working under ultra-low impedance, so
it can easily achieve large bandwidth and ultra low distortion.
Low distortion and large bandwidth is what all amplifiers want to achieve. Only with
ultra large bandwidth and high speed processing can an amplifier wonderfully
process sudden pulse wave signal, and achieve real playback of music signal
speed and transparency.
Traditional Voltage mode amplifiers always cause a Transient Intermodulation
Distortion (TIMD), which brings a harsh “metallic sound”, badly destroyed the
sound.To eliminate TIMD, designers usually adopts feedback circuit loop (low
feedback, partial feedback or negative feedback) in hardware but these don’t totally
settle the problem, and cost is very high.
While Questyle gives up the traditional voltage mode format, designed with a
“Current Mode” amplification. When the components is working in Current mode,
amplifier Slew Rate (SR) achieves a linear increase as input signal amplitude
increases, it is in proportion to input signal amplitude. When it’s input with large
amplitude signal, Current Mode amplifier SR is much larger than traditional Voltage
mode devices, it can totally eliminate TIMD and ensures large amplitude signal and
low distortion real playback.
Current Mode Amplification Technology
06 07
(China Intellectual Property Office Patent No. 201520211945.X )
Unlike other DACs that claim DSD support, yet in actuality provide DoP (DSD over
PCM), the Questyle Audio CMA800i accepts the DSD bit-stream directly from your
computer, bypassing your computer’s audio processing and digital volume control
as well as the Questyle Audio CMA800i’s digital filters, to provide True DSD, the
way it was meant to be heard, without requiring expensive difficult to install propri-
etary connectors, or as is the case with DoP breaking up the bit-stream into 16bit
packets and compressing them into a PCM data-stream and then uncompressing
them at the other end, buffering them, then reassembling the bit-stream so that it
may be sent to the DAC as DSD, all of which requires an extreme amount of
processing at both the computer end and the DAC end to perform in real time
True DSD（Direct Stream Digital）Technology
WM8741
DSD
PCM
DSD
DAC
PCM
DAC
DSD
PCM
True DSD DAC
PCM
DSD
PCM PCM
