PMA-NC252MP
As a manufacturer of electronic equipment I have been granted a web account for Hypex OEM web shop. My newly designed power amplifier based on excellent Hypex NCore modules is PMA-NC252MP. It is an amplifier with rated power 2x250W/4ohm and based on the NC252MP OEM modules.
Hypex NC252MP OEM module
The NC252MP amplifier module incorporates a low power standby power supply (meets 2013 ERP Lot 6 0.5W requirements), a highly efficient switch mode power supply and a high-performance Class D amplifier in one compact and easily applicable power brick.
The amplifier used in the NC252MP is a self-contained high-performance class D amplifier intended for a wide range of audio applications, ranging from public address systems to ultrahigh-fidelity replay systems for studio and home use. Chief distinguishing features are flat frequency response irrespective of load impedance, nearly frequency independent distortion behaviour and very low radiated and conducted EMI. Control is based on a phase shift controlled self-oscillating loop taking feedback only at the speaker output.
The main SMPS providing the power for the amplifier is a compact, high power, highly efficient, regulated half bridge converter with synchronous rectification on the main output rails. These properties make this technology ideal for powering Class D audio amplifiers.
PMA-NC252MP power amplifier
is built in a full-size aluminum case with side heatsinks, to allow for maximum continuous sine power without time and temperature limitations. It has large binding posts to allow for insertion of locking banana plugs. Input XLR connectors are standard Neutrik NC3FDM3-L-B-1. The goal is to get the most from the Hypex module, its full potential, especially in continuous sine power.
Class D high efficiency and lower dissipated power (compared to class AB amplifiers) is a temptation for most assemblers to use quite small amplifier case with not much heatsinking capability. This make a benefit of smaller size and weight, however the power capabilities of the Hypex modules are not completely utilized and reliability and life span may suffer. Let me quote from Hypex datasheets:
Class D amplifiers’ known high efficiency often leads to a gross underestimation of the cooling required. Please apply adequate cooling to the module to ensure the module operates within specification. The following graphs provide an indication of the heat (in Watts) generated at different output levels. For more information regarding cooling, please refer to our application note “Thermal Design”, available on our website. Defects caused by overheating due to poor thermal management are not covered by warranty.
So we can see that the proper heatsink and thermal management must not be underestimated. For this reason and to get maximum possible continuous power and maximum reliability of the amplifier, a full-size aluminum case with side heatsinks with fins was chosen. It also fits well to a main home audio system based on 400 - 450mm (19") wide components.
PMA NC252MP uses balanced inputs with Neutrik XLR connectors for optimal performance. The inputs can be connected to an unbalanced source, but the achievable S/N and ground loop immunity would suffer.
Front view of the amplifier
Rear view of the amplifier
Technical specifications
Measurements
The amplifier meets Hypex electronics specs that can be found in their datasheet
THD vs. output power at 1kHz into 4ohm load, one channel driven
THD vs. output power at 20Hz into 4ohm load, one channel driven
THD 5W/4ohm/1kHz (added 12/22/2021)
Thermal management
Due to the quite large case with heatsinks with fins, the amplifier runs cool under any output power.
Pavel Macura, December 21, 2021
================================================================================
June 3, 2022 - New measurements with my new E1DA Cosmos ADC A/D converter
As a manufacturer of electronic equipment I have been granted a web account for Hypex OEM web shop. My newly designed power amplifier based on excellent Hypex NCore modules is PMA-NC252MP. It is an amplifier with rated power 2x250W/4ohm and based on the NC252MP OEM modules.
Hypex NC252MP OEM module
The NC252MP amplifier module incorporates a low power standby power supply (meets 2013 ERP Lot 6 0.5W requirements), a highly efficient switch mode power supply and a high-performance Class D amplifier in one compact and easily applicable power brick.
The amplifier used in the NC252MP is a self-contained high-performance class D amplifier intended for a wide range of audio applications, ranging from public address systems to ultrahigh-fidelity replay systems for studio and home use. Chief distinguishing features are flat frequency response irrespective of load impedance, nearly frequency independent distortion behaviour and very low radiated and conducted EMI. Control is based on a phase shift controlled self-oscillating loop taking feedback only at the speaker output.
The main SMPS providing the power for the amplifier is a compact, high power, highly efficient, regulated half bridge converter with synchronous rectification on the main output rails. These properties make this technology ideal for powering Class D audio amplifiers.
PMA-NC252MP power amplifier
is built in a full-size aluminum case with side heatsinks, to allow for maximum continuous sine power without time and temperature limitations. It has large binding posts to allow for insertion of locking banana plugs. Input XLR connectors are standard Neutrik NC3FDM3-L-B-1. The goal is to get the most from the Hypex module, its full potential, especially in continuous sine power.
Class D high efficiency and lower dissipated power (compared to class AB amplifiers) is a temptation for most assemblers to use quite small amplifier case with not much heatsinking capability. This make a benefit of smaller size and weight, however the power capabilities of the Hypex modules are not completely utilized and reliability and life span may suffer. Let me quote from Hypex datasheets:
Class D amplifiers’ known high efficiency often leads to a gross underestimation of the cooling required. Please apply adequate cooling to the module to ensure the module operates within specification. The following graphs provide an indication of the heat (in Watts) generated at different output levels. For more information regarding cooling, please refer to our application note “Thermal Design”, available on our website. Defects caused by overheating due to poor thermal management are not covered by warranty.
So we can see that the proper heatsink and thermal management must not be underestimated. For this reason and to get maximum possible continuous power and maximum reliability of the amplifier, a full-size aluminum case with side heatsinks with fins was chosen. It also fits well to a main home audio system based on 400 - 450mm (19") wide components.
PMA NC252MP uses balanced inputs with Neutrik XLR connectors for optimal performance. The inputs can be connected to an unbalanced source, but the achievable S/N and ground loop immunity would suffer.
Front view of the amplifier
Rear view of the amplifier
Technical specifications
- balanced input impedance | 94 kohm
- frequency range | 10 Hz - 50 kHz (+0/-3dB)
- power bandwidth | 20 Hz - 35 kHz
- output noise voltage | 36uVrms (20Hz-22kHz unweighted)
- equivalent input noise voltage | 1.8 uVrms (20Hz-22kHz unweighted)
- output power | 2 x 250 W/4ohm
- output power, one channel driven | 300W/4ohm/1kHz/THD 1%
- S/N at 300W/4ohm | 119.6 dB
- THD and THD+N | see the datasheet and measurement below
- SINAD | 98.15 dB at 5W/4ohm/1kHz @22kHz BW
- CCIF IMD 19+20kHz | 0.0025%/20W/4ohm
- gain | 26 dB
- dimensions | 430 x 390 x 160 mm
- weight | 11 kg
Measurements
The amplifier meets Hypex electronics specs that can be found in their datasheet
THD vs. output power at 1kHz into 4ohm load, one channel driven
THD vs. output power at 20Hz into 4ohm load, one channel driven
THD 5W/4ohm/1kHz (added 12/22/2021)
Thermal management
Due to the quite large case with heatsinks with fins, the amplifier runs cool under any output power.
Pavel Macura, December 21, 2021
================================================================================
June 3, 2022 - New measurements with my new E1DA Cosmos ADC A/D converter
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