ACSS (Audio-gd Current
Signal System) is Audio-gd's system for transmitting audio signals in
the current domain. This concept, first seen in 1966, we have used for
many years, and since 2005, have evolved the technology to include all
audio signals in our systems from the digital source to the power
amplifier. Since 2006, ACSS comp5nts have become Audio-gd's most popular
NOS 7 is a real fully
balanced discrete design. Applies the 8 Pieces Expensive high-end grade PCM1704UK which can support up to
24Bit/192KHz through SPDIF input and 32 Bit / 384KHz through
USB / I2S input . Similar to other PCM1704UK designs , we applied Non-feedback ACSS
analog stages. The
8 pcs PCM1704UK feed to the ACSS analog
stages without any OPAs and couple caps so it can avoid sound coloration .
The ACSS is a non-feedback
technology made with fully discrete amplifiers. Most people know the
feedback design can offer better specs in test measurements, and
classic non-feedback can't do well in test measurements but can offer better
sound for the human's ears. Here is a conflict of the classic circuits.
But the ACSS opens a new field, it can offer a least coloration sound
which is more neutral with very low distortion and high linearity. So
it can retain the dynamics, detail and neutral sound but not sound
bright or harsh.
The output buffers are
Non-feedback. For low impedance, we applied the dual FET buffer output stage
which is quite less colored than most conventional circuits.
For the most real like sound reproduce, Mr.Kingwa had spend a long
term to design and rectify the new NOS DSP software personally, not
only based the the software codes , but he also well know on the
hardware compatible and sensitivity on the sound quality .
design had applied -6db /oct passive analog filter , you can hear
the wonderful sound of the NOS but you can't hear the noise as other
some NOS design .
may had 99 type prefers . We had design two NOS modes in the
software for users select. Since Oct. 12th. 2016, the new Ver 2
software had offer 3 Nos modes .
One is the
best speed data process, another is applied large algorithm to
process the data.
The full new
design concept had boost the PCM1704 support up to 768KHz even
1536KHz (test in emulation mode).
A high exact TCXO
for the DSP chip running in the asynchronous data process mode, it
don't want the source master clock input , which is reduce the
signal transmit request, FIFO design and rebuilt the clock by the
DSP chip, can refuse the jitter .
NOS 7 applies the excellent
8 pcs PCM1704UK
and excellent analog
output stages, but these are not the only keys of the best sound.
The power supply is most important. Even applying the best DA chip
and the best amp, if matched to a normal power supply, the total
sound may still be average or sound musical, but can't be neutral
and detailed. That is why it is easy to find hi-end grade gears
maybe without the best chips or amp stages, but with plenteous
dedicated DC supply circuits.
The NOS 7
total 21 PSU
groups are applied.
19 groups of high-quality class A parallel
connection PSU with dedicated DC supply double-stage PSU, which can
offer very clear DC power for the DAC,
a very black background and neutral sound characteristic. The
double-stage PSU is very important for digital parts. Some designs
may have very low jitter in theory, but if the power is supplied by
a dirty or low-speed power supply, it will increase the jitter and
pollute the data, and degrade the sound quality obviously.
The class A parallel connection PSU has very high input
impedance to avoid pulse through the PSU from affecting the DAC and
low output impedance with very fast speed and high linearity, so it
is a very clean power supply. In my experience, its sound is better
than battery power supply, better human sound and neutral.