Simple and short signal transfer is best:
The NFB-3（2015） applies the newest ESS high-end Sabre32 DA chip
ES9018 which can support up to 32Bit/384KHz input .
in voltage output model , there is -12DB THD+N worst , to be
achieve the best performance of ES9018 , must work in current
output model .
In some other ES9018 built in DAC design ,
ES9018 output signal have to through 3 step OPAs implement analogy
signal process .
The NFB-3（2015） had different design , applies Non-feedback ACSS
design. The ES9018 feed to the ACSS
circuit by balanced model without any OPAs .
The ACSS circuit naturally working in
current model and have design difference current input , it can
transfer the ES9018 current signal to output and implement the I/V
conversion in current model in one ACSS amp . And this ACSS amp only
have one current gain stage , the ES9018 output signal only through
one stage can arrive the output stages .
The shortest signal journey can reproduce the best
detail and dynamic, and almost without sound coloration , It can
show the real performance of the ES9018 .
So our ACSS design is the best combo with
ES9018 achieve the best performance .
The ACSS also is a non-feedback
technology made with fully discrete amplifiers. Most people know the
feedback design can offer better specs in test measurements, and
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 a diamond output stage
which is quite less colored than most conventional circuits.
The DAC is without couple
caps to avoid coloration. There are two OPAs built in as the DC serve to
keep the DC offset .
The 32bit / 384K USB interface
outputs a I2S signal to ES9018 .
Multi-ply Class A power supplies are the key of sound :
NFB-3（2015） applies the excellent DA chip ES9018 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 average 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 , but with plenteous dedicated
DC supply circuits.
A total of 2 groups class A PSUs and 5 groups linear
PSUs power supply for all
digital and analog circuits.
To achieve high S/N, the
control circuit is powered with separate regulator.
Diagram of the Class A PSUs for analogy parts