MUSMYS Clone A-75 Pure Class A Power Amplifier, Fully Balanced/Stereo 480W-960W, 1-8Ohm 110V/220V HiFi Home Audio Amp

A-75 technical parameters：

1： Rated continuous output power (20HZ-20000HZ)

Pure Class A: Stereo sound：

480W X2 1 ohm output

240W X2 2 ohm output

120W X2 4 ohm output

60W X2 8 ohm output

Fully balanced bridging：

960W X2 2 ohm output

480W X2 4 ohm output

240W X2 8 ohm output

2： Frequency response：

Continuous rated output ：20-20000HZ +0 -0.2db

1W output： 0.5-160000HZ +0 -3 dB

3： S/N signal-to-noise ratio full frequency band 118dB

4： Total harmonic distortion: 0.05 2 ohms 0.01% 8 ohms

5： Input impedance: 40K (balanced input), 20K (RCA input)

6： Input sensitivity: 0.87V rated continuous average output

0.11V output 1 watt power

7： Gain attenuator: MAX -3dB -6dB -12Db

Corresponding magnification: 28 25 22 16

8： Damping coefficient 1000

9： Amplification factor of 28dB

10： Static power consumption 260W, maximum power consumption 520W

11： Overall size 430W * 225 H * 500 Dmm

12： Net weight 28 (kg)

Features:

â—Class A output, 120W4 Ω Ã— 2 stereo sound

â—The output adopts 12 field-effect power transistors per channel, which can drive impedance as low as 1 Ω.

â— The input adopts an exclusive white master developed fully balanced low noise module, which can greatly expand the frequency response of music, improve sound clarity and intensity

â—The voltage amplification section adopts two sets in parallel to reduce input noise and improve dynamic range.

â—Adopting DC stabilization technology to ensure stable operation of the power amplifier.

â— Add (220V) voltage isolation technology to effectively isolate DC from entering the transformer.

"A-75" includes an upgraded version of the "MCS+circuit" with an initial slow charging amplifier circuit equipped with "MCS", an improved version of the multi-stage parallel circuit design, combined with a current feedback design, to ensure linear response at each level. The amplification unit circuit is connected in parallel to reduce noise, and a DC stabilized power supply is installed in the drive section and MCS+circuit to improve SN ratio and sound purity. The high-efficiency large transformer is stored in a metal cover, combined with a "super large pond" filtering group, to provide sufficient and stable power supply. The amplifier part adopts a fully balanced amplification circuit design, with 12 high-power field-effect transistors used for amplification output in each channel, achieving high-quality and high driving force. It provides pure Class A 60W x2 (8 Ω), 120W x2 (4 Ω), 240W x2 (2 Ω), and 480W x2 (1 Ω) true power amplification outputs. Provide powerful power output and super strong driving capability.

A good power amplifier must use a good iron core. We use imported Z11 whole strip silicon steel sheet, wrapped with pure copper wire, and refuse to make noise. With a maximum power of 850W, the instantaneous output can reach 1600 watts. When used in our A-75 power amplifier, it is effortless and will not become a bottleneck, providing a source of power for ultra strong thrust.

Adopting a brand new customized version of filtering

Super large capacity capacitor is the key to good sound of A75. We have invested heavily in customizing capacitors, and after strict testing and control, any slight nonconformity is eliminated. Therefore, our quality control is very strict

A single 160000VF, with 4 units per machine, is 640000VF, which is a true super large pond capacitor with a configuration comparable to 200000 RMB equipment.

A-75 fully balanced buffer amplification circuit

We have newly developed fully balanced and fully split buffer amplifiers, which effectively improve the signal-to-noise ratio and expand the dynamic range. The fully balanced amplification technology has advantages such as good symmetry, small distortion, high stability, and strong driving force compared to ordinary amplification technologies.

By adopting a fully balanced amplification circuit design, the performance of CMRR is greatly enhanced, and it has a high ability to suppress harmonic distortion,

However, fully balanced amplification requires strict matching of circuit components, and the number of components used will double, so it is mostly applied in professional models or advanced Hi Fi equipment. And the true A75 input buffer comes with a -3-6-12dB switching option, which can be paired with input impedance of different stages

In order to achieve the ultimate performance, the Accuphase A-75 has invested a lot of effort and financial resources in research and development. They found that the driving and control forces of a power amplifier are actually closely related to the internal resistance of the amplifier. A small internal resistance results in good control force, strong and clean sound, and the most direct data reflection of internal resistance is the "damping coefficient". They try every way to improve the damping coefficient. The first generation of classic A65 uses relays for horn protection, Its damping coefficient is 400. When it reaches 70, it uses ultra-low internal resistance and ultra large current MOSFETs for output horn protection, and its damping coefficient reaches an astonishing 800. This is already very impressive. However, only 4 years later, Accuphase launched a new flagship pure power amplifier, with an output power similar to the A70. What is the difference between the A-75 and the previous generation? The appearance looks the same. In terms of specifications, the signal to noise ratio of the previous generation is 121dB, and that of A-75 is 122dB; The damping factor of the previous generation was 800, while A-75 was 1000. Is this difference worth introducing a new model to replace? Technicians are like this, even if there is a 1dB difference, they still have to work hard to pursue it. This is the spirit of Hi End! Moreover, the damping factor has been increased from 800 to 1000, which is a significant progress. Therefore, a new replacement model A-75 will be launched,

Many shoddy amplifiers on the market usually use a 16A relay as the output damping coefficient, which is randomly written as over 1000, and the signal-to-noise ratio can actually be written as 150dB. It is also difficult for top audio manufacturers in the world to produce such data, and it can be basically judged as a false parameter.

Most power amplifiers on the market use relays for sound protection. Omron's commonly used high current relay has a maximum current of only 16A. For a high current output amplifier, this is a bottleneck. No matter how many power tubes or transformers there are, they are ineffective. The output relay is like a faucet and cannot withstand high flow, so the control of the speaker is not good. In severe cases, the relay may burn out and the speaker may be scrapped, The flagship power amplifier of the Golden Throat has already adopted ultra high current MOSFETs, so it will not become a bottleneck of the power amplifier. A single transistor can pass through 260A, and the relay is only 16A. The difference is clear at a glance.

1. SPEAKERS speaker output conversion: OUT-A speaker group A terminal has sound, OUT-B speaker group B terminal has sound, both OUT-AB speaker group AB terminals have sound, and OFF all terminals have no sound.

2. WMETER RANGE level indicator light intensity conversion: selected for 10W low volume input, 100W medium volume input, and 1000W high volume input.

3. POWER machine power on/off key: When pressed in place and self-locking, it is in the power on state. When pressed again in the power on state and rebounded into place, it is in the power off state.

4. IRPUT key: When the IRPUT key is pressed to lock in place, when the LINE light on the panel is on, it indicates that the RCA signal input is conductive. Press the IRPUT key again, and when the BALANGED light on the panel is on, it indicates that the balanced signal input is conductive.

5. GAIN signal input roll off: mainly aimed at signal source output sound that is too loud. When MAX is selected, the input signal does not

Operation switch:

When the Operation switch is switched to BRIDER, it is the signal input when the amplifier is bridged (the BRIDGE light on the panel is on, and when bridged, the speaker connection method is as follows: the positive pole of the speaker is connected to Group A Left L red terminal, and the negative pole of the speaker is connected to Group A Right red terminal). When the Operation switch is switched to NORMAL, it is the signal input when the amplifier is not bridged (the BRIDGE light on the panel is off).