Questyle audio Cas192d User manual

CAS192D

POWER INPUT DFR UPSAMPLING

USB:44.1K up to 176.4K

Digital Filter:IIR Apodising

CAS192D

音频解码器

用户手册

www.questyleaudio.cn

CAS192D

Digital-to-Analog Converter

CAS192D

POWER INPUT DFR UPSAMPLING

USB:44.1K up to 176.4K

Digital Filter:IIR Apodising

www.questyleaudio.com

Contents

Features ........................................................................................

Check List .....................................................................................

Front View .....................................................................................

Rear View ....................................................................................

Input and output ............................................................................

True DSD Technology ....................................................................

PCM Version Digital Filters ...........................................................

Dual Clock Integral Upsampling ...................................................

CAS System Requirement ............................................................

Setup on Windows OS ................................................................

Setup on Mac OSX System ...........................................................

Specification ................................................................................

Thanks for selecting the Questyle Audio CAS192D Digital to Analogue Converter.

True is best. The Questyle Audio CAS192D is the world’s first USB DAC to support

true DSD mode.

The Questyle Audio CAS192D is an upgrade from Questyle’s previous flagship

model, the “D” stands for “(True) DSD”. The Questyle Audio CAS192D is designed

to process DSD files in their native format, without conversion to PCM.

The Power supply section is upgraded as well. Customized Plitron toroidal trans-

former, Schottky rectifiers, 22pcs Nichicon 2200uF FG capacitor, 22 groups of

individual power regulators, all to ensure each section, a stable and purified power.

The DAC chipset uses 4 levels of digital filter and power regulation.

Furthermore, Questyle Audio’s 3X Clock USB Asynchronous transmission structure

is maintained in the Questyle Audio CAS192D design. And in PCM mode, the

Questyle Audio CAS192D still provides 5 switchable digital filters, in which the IIR

(MP) filter eliminates Pre-Ring from pulse wave. The upsampling button is switch-

able between on and off, allowing convenient sound performance comparisons.

The DAC chipset is Wolfson WM8741, with an improved LPF and buffer stage,

changed to DALE resistors, to achieve overall a more stable performance and more

purified sound.

The Questyle Audio CAS192D aluminum chassis is produced by precise CNC

tooling machine. The upper cover and bottom chassis “mutual bit” structure design,

provides CAS192D with stable heat, excellent control of sympathetic vibration and

excellent shielding of RFI/EMI radiation.

Input and Output

- USB input supports 192kHz /24bit PCM and DSD mode

- 192kHz/24bit Standard Coaxial, Optical input

- USB 3X Clock Asynchronous transmission structure

- Dedicated USB drive program ensures stable transfer and compatibility

- Balanced (XLR) and unbalanced (RCA) output

- Neutrik jacket for XLR output

DA section features

- Wolfson WM8741DAC Chipset

- Support True DSD format digital to analog converting

- DAC chipset power utilizes 4 level filters and power regulators.

- LPF and buffer all utilize WIMA FKP2 capacitors, providing large dynamic and

powerful sound

- In PCM mode it provides 5 switchable digital filters, the IIR (MP) filter eliminates

the pre-ring from pulse wave.

- Customized Plitron toroidal transformer

- Schottky rectifiers, 22pcs Nichicon 2200uF FG capacitor, 22 groups of power

regulators

Check List

Features

CAS192D

Power Cord

CD-ROM

User Manual

1pc

02 03

①　Balanced output for Right Channel

②　Unbalanced output for Right Channel

③　Unbalanced output for Left Channel

④　Balanced output for Left Channel

⑤　SPDIF input

⑥　Optical input

⑦　USB input, type B

⑧　AC power socket

⑨　AC power fuse

⑩　AC power ON/OFF Switch

Front View Rear View

04 05

CAS192D

POWER INPUT DFR UPSAMPLING

USB:44.1K up to 176.4K

Digital Filter:IIR Apodising

1236

8 97

①　Standby Button. Press to power up CAS192D or return to standby.

②　AC power indicator.

③　LCD display, indicates the device working status.

④　Input selection button.

⑤　Digital filters button.

⑥　Up-sampling button.

⑦　Input mode indication.

⑧　Original sampling rate.

⑨　Upsampled rate.

⑩　PCM version digital filter.

11　PCM version digital filter mode

Note: in True DSD version, digital filter indicates “NO”.

BALOUT R BALOUT L COAXIAL IN OPTICAL IN USB INOUT R OUT L

2 3 41 56 7 8910

The Questyle Audio CAS192D is equipped with USB, SPDIF, Optical inputs, all

support 44.1K-192K sample rate, 16-24bit PCM resolution. All inputs support digital

filters switchable and dual clock integral upsampling technology.

The Questyle Audio CAS192D internal processor will automatically recognize the

input signal sample rate, automatically update and configure it, and show it in the

OLE display. This will set the user free from setup troubles.

Output is provided with Balanced (XLR) and Unbalanced (RCA) two options.

When The Questyle Audio CAS192D is turned on, its analog output will perform a

self inspection, to ensure the whole system is in “good” status, before activating the

output relay. When it’s turned off, the relay will immediately cut analog output, so as

to avoid any pulse wave damage to the system.

Input and output

（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 CAS192D 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 CAS192D’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

(China Intellectual Property Office Patent No. 201520212711.5)

Generated signals from piano, percussion and guitar contain a large amount pulse

wave. Studies of the sound psychology indicate that our ears are very sensitive to

the pre-ring of impulse wave. It makes music incoherent and unnatural. The

pre-ring, brought by FIR (finite impulse response) digital filters used in traditional

digital to analog conversion, can be tested and heard very easily. The Questyle

Audio CAS192D has the most advanced IIR digital filter, which completely

eliminates the pre-ring from the impulse wave and brings the most natural sound.

dCS is an example of a company using IIR digital filter technology.

Different digital filters have different impulse responses and group delay, creating

different subjective listening experiences. On the front panel of CAS192D, there is

a DFR button providing 5 different digital filters for user to choose. Among the five

digital filters, the pulse responses of IIR and FIR are totally different. Different FIR

or IIR digital filters have different frequency responses. The digital filters are switch-

able based on user’s favorite.

Vibrating objects in nature produce a sound wave which has similar features to the

IIR digital filter. There is no pre-ring before the vibration and the vibration amplitude

decreases gradually after the vibration.

PCM Version Digital Filters

08 09

Step1

Connect power cord to your CAS192D and a suitable 110v/220v A/C power source.

Assure the master power switch on the back of your CAS192D is in the “Off”position

(blue indicator light on the front panel will be off).

Step 2

Connect balanced interconnects from the Right and Left “Balanced” outputs of your

CAS192D to the Right and Left “Balanced” inputs on your CMA800R.

Step 3

Connect USB 2.0 cable from the USB output on your PC to the USB input on the

back of your CAS192D.

Step 4

Insert the Driver Disc provided with your CAS192D into your PC. Open the folder

Labeled DSD-1.05 and double click Setup.exe. When the installer tells you to

connect your CAS192D turn the master power switch on the back of your CAS192D

to the “On” position (blue indicator light on the front panel will light), then press the

power button on the front panel of your CAS192D (the front panel display will light

up), then hit “Continue” on the installer and follow the installer instructions.

Step 5

Once the drivers are installed, and the front panel of your CAS192D indicates

“Ready”, Go to Control Panels/Hardware and Sound and open “Sound”. “Questyle

CAS192D” should be set as default, highlight “Questyle CAS192D” and select

“Properties”. Click on the “Advanced” tab and set “Default Format” to “24 bit,

192000 Hz (Studio Quality)”, then click OK and OK again.

Step 6

Launch JRiver Media Center. Click on “Tools” and select “Options”. On the left side

of the “Options” window “Audio” should be highlighted. On the right side of the

“Options” window, under “Audio Device”, click on “Default Audio Device” and you

should see “Questyle CAS192D”. Select “ASIO for C-Media USB Device [ASIO]”.

Under “Settings” click on “DSP & output format” and the “DSP Studio”window

should pop up. Under “Sample rate”, next to “176,400 Hz” click on the words “No

change”and select “88,200 Hz”. Close the “DSP Studio” window by click the “X” in

the upper right corner. Click on “Bitstreaming” and select “Custom” check DSD then

click “OK”, and OK again.

Your CAS192D is now ready to playback True DSD. Follow JRiver Media Center

instructions for loading your music library and creating playlists. When playing DSD

files, the front panel display on your CAS192D will say “True DSD”, when playing

PCM files, it will reflect the sample rate of that file.

WM8741

DSD

PCM

DSD

DAC

PCM

DAC

DSD

PCM

True DSD DAC

PCM

DSD

PCM PCM

(which invariably leads to latency, data loss, etc), not to mention a 33% increase in

bandwidth requirements for the USB ports and cabling.

Dual Clock Integral Upsampling

10 11

CAS192D IIR digital filter pulse response CAS192D FIR digital filter pulse response

To maximize the performance of digital to audio conversion, up sampling technolo-

gy is widely used in high-end digital audio. In most designs, the up sampling goes

up to 192K no matter what the sample rate of the signal is. In the digital audio indus-

try, many scholars believe that there will be some error when doing non-integral

ASRC, which will cause distortion and degrade the sound quality. Being different

from those designs, the Questyle Audio CAS192D has two clocks with extremely

low phase noise, thus the processor automatically identifies the sample rate and

makes it up integrally.

For instance, a certain DAC is configured with single clock, the input data, whether

44.1K or 48K, will all go up to 192K. 48K is multiplied times 4 to get 192K; for

44.1kHz to go up to 192K, the multiples will be 4.3537... (192/44.1 = 4.3537...)

which is an infinite non-repeating decimal. In this case there will be too much

required computation and round-off errors. But for the Questyle Audio CAS192D, if

the input data is 44.1kHz, it will be multiplied by 4 to 176.4kHz; if the input data is

48K, it will be multiplied by 4 to 192K, which can avoid those negative effects. The

upsampling is ASRC, and it can avoid Jitter. On the front panel of the Questyle

Audio CAS192D, there is an UPSAMPLING button for starting up or shutting down

the function of upsampling, and the current state of operation will be clearly seen on

the screen.

The Questyle Audio CAS192D will memorize the user’s operation of upsampling.

The following is the THD+N and amplitude curves for non upsampling and upsam-

pling, working at 48K sample rate with -3dBFS,24bit data.(Blue is for non upsam-

pling; purple is for up sampling).

When the sample rate is as low as in 44.1k or 48k, the 5 digital filter options of the

Questyle Audio CAS192D will be:

- IIR Apodisting

- IIR soft-knee

- IIR Half-band

- FIR Apodisting

- FIR Half-band

When the sample rate is as high as in 88.2k, 96k or 192kHz, the 5 digital filter

options of the Questyle Audio CAS192D will be:

- IIR Apodisting

- IIR soft-knee

- FIR soft-knee

- FIR Apodisting

- FIR Brickwall

The Questyle Audio CAS192D will divide the user’s configuration of digital filters

into high and low groups and memorize the sample rate.