Mono COPY Purifi DS9040 ET9040BA Circuit HIFI Pure Amplifier XLR/RCA Input 350W 2/4/8Ohm 110/220V

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The power amplifier part of DS9040 is produced based on the reference ET9040BA circuit architecture, with some adjustments and designs made by ourselves.

The power amplifier adopts a BTL fully differential balanced circuit, featuring automatic correction of balance errors in both channels and adjustable fine tuning, paired with a unique feedback design. This design enables self-excited oscillation in response to the output signal, allowing real-time correction of the comparison signal. Compared to traditional triangular wave comparison methods, it significantly reduces nonlinear distortion caused by modulation. Additionally, through outer-loop negative feedback, the power amplifier maintains consistent frequency response under any load, while traditional similar schemes may exhibit inconsistent high-frequency response under different loads.

The high quality of the product is inseparable from the carefully selected component combinations. Many components are rare and new materials, with long ordering cycles, and the ordering time for some resistors can be as long as five months. We are unwilling to compromise and use alternative components. It took nearly two years to launch this product, during which we optimized the layout four times and ultimately adopted an integrated design of buffer and power amplifier. This design can maximize the performance impact of output connectors under low impedance load and high current conditions, while minimizing the high-frequency ground loop area and reducing potential difference interference between PCB boards. Since Class D power amplifiers all operate at high frequencies, a complete grounding design is crucial for performance.

With the rapid development of the third-generation wide bandgap semiconductors SiC and GaN, they can bring more or less benefits to the audio field. Therefore, we have focused on optimizing the power supply part this time. The operating frequency of traditional MOS switching power supplies is mostly below 100 kHz, and the noise generated by their switching frequency can generate harmonic interference downwards. Calculating based on the 7th harmonic, 100 kHz/7 ≈ 14 kHz, which falls within the audible range of audio. With the development of the third-generation semiconductor SiC devices, it has become easier to increase the operating frequency of switching power supplies. The DS9040, paired with a 3000-watt silicon carbide (SiC) device power supply, operates at a frequency of over 360 kHz without affecting efficiency, staying far away from the audible range of audio and significantly improving the auditory impact brought by the power supply.

In the single-channel version, we allocated the saved space to add a linear power supply for the operational amplifier. This linear power supply is customized by a large Danish supplier according to their standards, with an additional 3-layer magnetic shielding. We have tested transformers from multiple brands, including Talema, Arrowhead, and some domestic manufacturers, but none of them met our expected requirements. The transformer we ultimately chose comes from a listed company, with its iron core produced in-house. Such high-quality iron cores were originally used to supply precision instrument users worldwide. The disadvantage of this brand of transformer is its higher cost. With the same power output, its volume is about twice that of products from other suppliers. However, on our previous DT700 product, it has received unanimous praise from users

This device is available in two versions: single-channel and dual-channel. It is equipped with Class A discrete operational amplifiers, SS2590 and OP2-BP. All versions feature discrete SS78XX and SS79XX low-noise, high-current voltage regulators for the voltage stabilization section. Due to the specialized harmonic calibration of this product, calibration is performed in conjunction with the operational amplifier. Changing the operational amplifier calibration parameters will result in slight variations. If you intend to replace the operational amplifier, please note the position of each one for easy restoration. Our unique design includes buffer operational amplifier bypass and coupling capacitor jumper, both maintaining the previous 400A (6525) style. By default, the coupling capacitor jumpers are set to direct coupling. If the front-end device has a poor VOS and produces DC output, you can manually adjust the jumpers to add a coupling capacitor.

Difference between single-channel and dual-channel:

All circuit boards are the same, with the only difference being the power supply. Each single channel has one power supply, providing stronger power and more reserve power. When connected to a line-in, the sound quality may be slightly mellow in the mid-to-high frequencies, depending on personal preference. Some people may find it less crisp.

Regarding power, the power listed in our table is the actual RMS test power. Some friends may ask, isn't the module power greater? However, that power is tested when the power supply is in an ideal regulated state. In reality, due to the voltage of the power transistor being 100V, the positive and negative power supplies cannot exceed 50V, and after leaving a margin, only 45V can be used for power supply. Many actual test power values on foreign evaluation websites also fail to reach this level. For open-loop power supplies like those paired with Hypex SMPS120O-180, the actual power cannot possibly reach the official module rated power. Therefore, please do not use other people's false ratings to inquire about our power.

The following results are real‑world measurements of the unit. Due to limitations of test equipment, readings are close to the instrument’s loop‑back baseline, for reference only. Better test gear will yield superior figures.
The first graph shows IMD test results. The original first‑batch ET9040BA units had known performance issues. We include this real‑measurement graph to address concerns from audiophiles.

Detailed Specifications

Product Model: DS9040
Product Type: Pure Power Amplifier
Output Power: 350W/8Ω2, 650W/4Ω2, 1000W/2Ω*2
Gain: 27dB/23dB
Input Sensitivity: 2.4V/350W
Input Impedance: Balanced 10.2KΩ, Unbalanced 5.1KΩ
THD Total Harmonic Distortion @1KHZ: â‰Â¤0.0001%
THD+N @1KHZ: â‰Â¤0.00015%
Noise: â‰Â¤25uV
Signal‑to‑Noise Ratio: â‰Â¤Ã¢€‘125dB
Frequency Response: 10HZ‑30KHZ ±0.1dB
Damping Factor 1KHZ 8Ω: >1000
Input Interfaces: RCA, XLR

Product Functions

Volume Adjustment: None
Protection:

1. Amplifier over‑current protection

2. DC protection (also known as loudspeaker protection)

3. Thermal protection

4. Power‑on delay

5. Under‑voltage protection

Power / Consumption

Input Voltage: 220‑240V/ 100‑120V (Please make a note for 110V version)
Quiescent Power Consumption: â‰Â¤35W
Overall Efficiency: 93%
Rated Consumption (Dual‑channel, 200W 8Ω): 420W (Average power for music operation: 1/8 of rated power)

Dimensions / Weight

Unit Dimensions: 36926680MM
Package Dimensions: 430375150MM
Net Weight: 7.2Kg
Gross Weight: 8Kg