Xiangsheng 728A Super Sound Quality Marantz 7 Tube Amplifier Preamplifier XS HIFI Fever DAC Front 8675 Bluetooth AC110V/220V
Performance parameters:
Size: 435×90×290mm
Input impedance: 100K; output impedance: 600 ohms;
Signal to noise ratio: 90dB;
Frequency response: 20Hz--30KHz (plus or minus 1dB);
Distortion: 0.01%.
Output Tube 12AT7/ECC81 × 2, 12AU7/ECC82 × 2, Rectifier tube:6Z4 × 2
Silver remote：
Black remote：
no Bluetooth models:
Bluetooth models:
728A has
been produced and sold for more than ten years. It has been improved
many times. It uses 4 antique oil-immersed capacitors to couple, and
mixes with polypropylene capacitors such as German WIMA and ERO
capacitors and Siemens capacitors with good resolution, making the sound
warm and delicate without losing resolution. !
(Since
the oil-immersed capacitors are all produced in the old Jun factory
many years ago, they are all in stock, so different batches of
capacitors may have different appearances and appearances. If you mind,
please go around, so as not to be unpleasant!)
The
internal signal line of this machine adopts imported Teflon
silver-plated wire, which is very helpful to improve signal details,
reduce signal loss, and reduce induced noise. This machine has adjusted
the line parameters for modern high-level audio sources to ensure that
large signals can pass through easily without clipping.
This
machine has no bottom noise! If noise occurs, check whether the signal
line is shielded! Whether the ground wire forms a loop! And whether
there is a ground potential difference!
The line
launched by Wada Shigeru in the early 1960s has excellent performance.
It maintains the mellow and musical characteristics of Marantz7. At the
same time, it is better than Marantez7 in terms of dynamics, transients,
high and low frequency response, analysis power, and signal-to-noise
ratio. It also keeps pace with Marante7 in terms of sound field and
transparency. .
The improved 728A electronic tube
front stage is one of our company's most popular products recommended by
customers and dealers. It has mature design, outstanding sound quality,
stable performance, and good reputation. It is popular at home and
abroad. This machine can be connected to a pure power amplifier; it can
also be connected to a parallel machine as a tone adjuster to further
improve the sound quality. The actual sound quality of a sound system is
importantly related to the sound source, the front and rear levels of
the power amplifier, and the quality of the speakers. If the other parts
of the system are balanced and reasonable, the sound quality of this
machine will not disappoint. You can consult online customer service
before purchasing the machine, objectively Give reference suggestions.
1. Product introduction:
This
machine has been improved many times on the basis of the
third-generation 728 liner pre-stage. Compared with the original
machine, the appearance is elegant and solemn, and the taste is
extraordinary. In addition to retaining all its advantages, it also adds
the following advantages:
1. It is designed with circuit board, the internal layout is more reasonable, neat and beautiful.
The
front panel adopts a silver 6mm thick aluminum alloy electroplating
drawing process panel, a blue power indicator tube, and a unique
electronic tube display large window. The background uses a warm red
orange, and the grade is higher (see the picture below).
2. High-grade sandblasting paint craft thin steel box, high-gloss metal knobs, honeycomb type big machine feet.
3.
Signal input 4 groups of stereo switching, using traditional rotary
switch to control advanced fully sealed relay to realize signal
conversion, avoiding switching noise and long life.
The
signal output adopts the relay delay. After the amplifier tube enters
the stable working state, the relay pulls in the output signal, avoiding
the unpleasant noise generated by the electron tube during the
preheating process.
4. The output signal provides
two sets of outputs, which can play a bi-amp system. (The instructions
indicate that there are high and low levels. Now the machine has no
distinction between high and low. Both sets of output are the same.
Actually The machine shall prevail)
5. The input and output interfaces are all gold-plated RCA lotus seats to reduce contact resistance.
6. The power inlet adopts a three-plug socket, which is easy to replace and upgrade the power cord.
7.
Designed with grid filtering and purification circuit, which can filter
out the clutter interference and DC components in the grid.
8. Use antique oil-immersed capacitors and imported WIMA and other polypropylene capacitor coupling.
9.
The high-performance R cattle in the transformer is used for power
supply, and the price is high (the ring cattle and the square cattle
have large magnetic leakage, large radiation noise, and low efficiency,
while the R cattle efficiency is as high as 90% or more, and the
magnetic drain is small).
10. The high voltage is rectified by electronic tubes, and two are connected in parallel to provide enough current.
11.
Two large pond filter capacitors plus inductance filter form a CLC
filter circuit with good filtering effect and suppress residual noise.
12.
The electronic tube filament adopts AC power supply, which is warmer
and more durable than DC power supply. It will not cause sound hardening
and prolong the life of the electronic tube. And to ensure that the
interference of the filament is minimized.
