The line introduced 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, and it is also on par with Marante7 in terms of sound field and transparency.
This is the latest version of our improved 728A, with mature design, outstanding sound quality and stable performance. It can be connected to a pure power amplifier; it can also be connected to a parallel machine as a tone adjuster and further improve the sound quality.
Product description:
advantage:
1. Designed with circuit boards, 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, which is of higher quality.
2. High-grade sandblasting paint craft thin steel box body, high-gloss metal knobs, honeycomb type big machine feet.
3. Signal input 4 sets 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 a relay delay. After the amplifier tube enters a stable working state, the relay pulls in the output signal to avoid the unpleasant noise generated by the electronic tube during the preheating process.
4. The output signal provides two sets of outputs, which can play a bi-amp system (the instructions are marked as high level High and low level Low. Now there is no distinction between high and low on the machine. 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 a grid filtering and purification circuit, which can filter out 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.
11.2 large water pond filter capacitors plus inductance filter to form a CLC filter circuit with good filter effect and suppress residual noise.
12. The electronic tube filament uses AC power supply, which is warmer and durable than DC power supply, will not cause sound hardening, and prolong the life of the tube. And to ensure that the interference of the filament is minimized.
Product parameters:
●Size: L435*H90*W290 MM
●Input impedance: 100K; output impedance: 600 ohms
●Signal to noise ratio: 90dB
●Frequency response: 20Hz--30KHz (plus or minus 1dB)
●Distortion: ≤ 0.01%
●The internal wiring of the machine: 12AT7×2, 12AU7×2, 6Z4×2
●The net weight is about 6 kg, and the gross weight of the package is about 9 kg
