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Sample rates up to 384 kHz and DSD
DAD were the first to design converters that handle sample
rates up to 384 kHz. The AX32 follows the track of the
renowned AX24 with an enhanced performance on the
standard sample rates and the high sample rates like 192 kHz,
DXD, 384 kHz and the one bit DSD format.
Dual 5 bit @ 6.14Mhz A/D conversion
The outstanding sound quality of the AX32 is achieved by an
extreme attention to detail in every part of the circuit design.
One of these details is the use of two parallel A/D converters
per channel to increase the dynamic range.
Another very important detail is the use of the DAD ultimate
high resolution conversion technology using the higher order
6.14Mhz 5 bit delta sigma modulator of the ADC chip. Rather
than using the decimation filters built into the ADC chip, we
feed the output from the modulator to a DSP featuring DAD
designed and optimised decimation filters, allowing us to
provide all sample rates in the highest possible quality.
Accurate Mic-pres with relay gain system
The AX32 mic pre’s have an outstanding performance with an
equivalent input noise below -130 dB. A resistor-based gain
step circuitry with relays ensures that no un-linear distortion is
added to the sensitive microphone signal when amplified.
Each 0.1 dB gain step is digitally compensated for an inter
channel accuracy of 0.1 dB.
128 times oversampled D/A with DXD and true DSD
The D/A converter provides an ultimate natural conversion and
relies on a high resolution design with 128 times oversampled
output of the PCM sample rates, using DAD optimized
reconstruction filters, as well as a true-DSD output provided by
the same modulator and filter system. The analogue output
level is adjusted by a level step circuitry using relays in
combination with a digital gain circuitry and a mute system
ensuring high dynamic range, and still no disturbing clicks
when changing formats or powering down.
Low latency routing and signal processing
The AX32 and DX32 units are internally distributing all the I/O
signals via a 1,500x1,500 I/O matrix, which also provides a
channel based processing and a 32 bit floating point summing
processor. The matrix provides fixed-latency asynchronous
routing of all inputs to one or more outputs with a time stamp
mechanism. This ensures a fixed latency of 5 audio samples
from all digital inputs to all digital outputs. All the sample rates
from 44.1 kHz to 384 kHz and DSD are supported. Due to the
nature of the DSD format, no signal processing is however
possible when operating in DSD mode.
Specications
Dynamic range, ADC (A) > 123 dB
THD + N, ADC (A) < -120 dB @ -6 dBFS
Dynamic Range, DAC (A) > 128 dB
THD + N, DAC (A) < -115 dB @ -6 dBFS
Cross talk (A) < -120 dB
Mic Equivalent noise (A) < -130 dB @ 100Ω
Mic gain range - 18 to +70 dB
Mic gain step accuracy < 0.25 dB
Sample-rates 44.1 to 384kHz, DSD64,
DSD128 (DoP)
Clock accuracy < 2PPM via Digital PPL
Dynamic Range
d
B
F
S
A/D
+0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
2.5k 5k 7.5k 10k 12.5k 15k 17.5k 20k 22.5k
Hz
A/D Conversion
d
B
u
Frequency Response A/D-D/A Conversion
+15
+10
+5
+0
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
10k 20k 30k 40k 50k 60k 70k 80k 100k 200k
Hz
48kHz 96kHz
DSD64
384kHz
192kHz
DXD
88.2kHz
44.1kHz
176.4kHz
DSD128
d
B
F
S
-120 -100 -80 -60 -40 -20 +0
d
B
r
A
A/D
D/A
A/D dBr
D/A dBFS
THD+Noise A/D and D/A conversion
-90
-92.5
-95
-97.5
-100
-102.5
-105
-107.5
-110
-112.5
-115
-117.5
-120
-122.5
-125
-127.5
-130
D/A Conversion
A/D Conversion