Australian HiFi — May-June 2017

Australian Hi-Fi 45

Questyle Reference System Golden Edition

-140.000Hz 4000.00 8000.00 12000.00 16000.00 20k

-120.00

-100.00

-80.00

-60.00

-40.00

-20.00

dBFS0.00 .EWPORT4EST,ABS

-140.000Hz 4000.00 8000.00 12000.00 16000.00 20k

-120.00

-100.00

-80.00

-60.00

-40.00

-20.00

dBFS0.00 .EWPORT4EST,ABS

-140.000Hz 4000.00 8000.00 12000.00 16000.00 20k

-120.00

-100.00

-80.00

-60.00

-40.00

-20.00

dBFS0.00 .EWPORT4EST,ABS

-140.0010.00 Hz 100.00 1000.00 10000.00

-140.00

-130.00

-120.00

-110.00

-100.00

-90.00dB .EWPORT4EST,ABS

Graph 11:THD at -90.31dB (dithered 44.1kHz/16-bit

test signal). Questyle CAS192D.

Graph 10:THD at -89.46dB (undithered 44.1kHz/16-

bit test signal). Questyle CAS192D.

Graph 15:“ȭǜƬʁƋǒŘȭȭƬǚ,ʁɁʊʊǜŘǚǘƖ³ƬǢȊõǔǷǒǜɤŽǚŘƋǘ

ǜʁŘƋƬɦŘȭƞʁǔǷǒǜȊǚƬǢɤɡˁʁɡǚƬǜʁŘƋƬɦˁʊǔȭǷǮƶǘŒ ̆ʤʹǮȊŽǔǜ

signals. Questyle CAS192D.

0.0001020Hz 100.00 1000.00 10k

0.00100

0.01000

0.10000

1.00000

5.00000

%

.EWPORT4EST,ABS

-140.000Hz 9600.00 19200.00 28800.00 38400.00 48k

-120.00

-100.00

-80.00

-60.00

-40.00

-20.00

dBFS0.00 .EWPORT4EST,ABS

0.00010-80.00 dBFS -60.00 -40.00 -20.00 0.00

0.00100

0.01000

0.10000

1.00000

5.00000

%

.EWPORT4EST,ABS

Graph 13: “ȭǜƬʁȧɁƞˁǚŘǜǔɁȭƞǔʊǜɁʁǜǔɁȭɤ,,“õȊ“À<ɦ

using 44.1kHz/16-bit test signals. Questyle CAS192D.

Graph 12: THD vs Frequency with 48kHz/24-bit

ǜƬʊǜʊǔǷȭŘǚʊŘǜ̋ƞ*ɤǚƬǢƋǒŘȭȭƬǚƅǷʁƬƬȭƇʁǔǷǒǜƋǒŘȭȭƬǚ

ƅʁƬƞƇɦŘȭƞŘǜȊʹ̋ƞ*ɤǚƬǢƋǒŘȭȭƬǚƅɡˁʁɡǚƬƇʁǔǷǒǜ

ƋǒŘȭȭƬǚƅ˿ƬǚǚɁ˹ƇɦƖóˁƬʊǜ˿ǚƬ,Äăɍȳʹ<Ɩ

Graph 14: THD vs Level. AES-17 24-bit/48kHz test

signals. Questyle CAS192D.

Graph 9: THD at -10dB (44.1kHz/16-bit test signal).

Questyle CAS192D.

The frequency response of the Questyle

CAS192D is shown in Graph 5 for four differ-

ent settings of the fi lters and you can see that

with the exception of the FIR brick wall fi lter,

which cuts off steeply just before 20kHz (you

can see why it’s called a ‘brick wall’ fi lter!), all

other fi lters roll off very gently, to be around

0.2dB down at 20kHz, for a normalised

response of 20Hz to 20kHz ±0.1dB. The fre-

quency response of the Questyle CAS192D is

even-further extended when oversampling is

switched on, as you can see in Graphs 6 and

7 which show the impulse response, but also

serve to show high-frequency response, with

Graph 6 showing the response without over-

sampling and Graph 7 with oversampling.

You can see the extension of the response

when using oversampling.

Newport Test Labs tested the Questyle

CAS192D using both CD-standard digital

signals (44.1kHz/16-bit) and AES-17-standard

digital signals (48kHz/24-bit), the results of

which are shown in the respective tabulated

results, and in the graphs. Graph 8 shows

THD for a 0dB CD-standard signal and you

can see that with the exception of the third

harmonic, at –95dB (0.00177%), all harmonic

distortion components are more than 100dB

down (0.001%) and most are more than

120dB down (0.0001%). Reducing the level

of the test signal by 10dB, which gives the

results that you would expect when playing

music (which is never recorded at 0dB) the

Questyle CAS192D returned the results

shown in Graph 9, with a third harmonic at

–108dB (0.00039%) and all other harmonics

(and note there are fewer than there were at

0dB) are more than 120dB down (0.0001%).