Audio-gd products had
design and test based on the AP SYS-2722 (The top-drawer
professional equipment in world)
Class A design built by discrete analog stages without any OPA or coupling caps in the signal channels.
Non- feedback ACSS and output stage designs
Total applied 4 pcs exact matching 150W transistors
offer the strong power output
Class A output 3500MW at 25 ohm ,drive most headphones can
working under pure class A state
40W transformer ,Class A PSU's for DC supply.
Uses most Hi-end grade parts and exactly matched transistors, OCC
6 DB and 16DB gain can drive the high and low sensitivity headphones
3 groups input:
RCA X2, ACSS X1
Preamp output : RCA
Headphone amp output:
Detail of the Current Conveyor (ACSS) Technology
There are a lot different DACs in worth, they had different design
and output impedance . For avoid the sound quality effect by
different DAC's output impedance, in the NFB-3AMP, it had design a pair
single-ended class A FET buffers in the input . All the RCA input
signals through these FET buffers, the output impedance had become
very low, even the source had high or low output impedance.
buffers working on pure class A state, and it is so short signal
journey , it can keep the sound quality without coloration ,dry and
NFB-3AMP had the same ACSS design . It
is a class A design built by discrete analog stages without any OPA or coupling caps in the signal channels.
They seem complex , but in fact they are the most simple design
the world has ever had , their a lot components to process the power
supply. The simplest and shortest signal journey brings out the
most neutral and least colored sound.
The ACSS is a non-feedback
technology made with discrete amplifiers. Most people know the global
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.
All signal gain is in current
area, all transistors
work in pure class A mode.
The NFB-3AMP has all components
exactly matched before installation.
Super low THD ¡]Test by AP
SYS-2722,0DBV output level) Flat
frequency response ¡]Test by AP SYS-2722)
Strong class A output stages:
The NFB-3AMP had design a pare diamond difference output stages, every
parts had exact matching before assemble so don't need any human
output stages had two pair 150W transistors ,they also working
under class A state .
class A parallel connection PSU has very high input impedance to avoid
pulse through the PSU from affecting the preamp and low
output impedance with very fast speed and high linear, so it is a very
The NFB-3AMP applies seperate linear PSUs for the
display and control parts, avoid the disturbances through power line
from affecting the amplifier.
Uses all Hi-end
components, including DALE resistors, WIMA caps, custom
order NOVER (UK brand) caps.