FWIW, AI says the 5 minute test should be performed at 6 frequencies. I don't know where that comes from. So that would be more than a half hour of testing.
The
5-minute continuous operation test should be performed at
each frequency where the amplifier is tested for maximum power output. According to the FTC's guidelines for testing the power output of audio amplifiers, you should test the amplifier at multiple frequencies across the full range of human hearing (20 Hz to 20,000 Hz). Typically, the
FTC-recommended frequencies for measuring and testing the continuous power output include:
- 20 Hz
- 100 Hz
- 1 kHz
- 5 kHz
- 10 kHz
- 20 kHz
Therefore, the
5-minute continuous operation test should be performed at
each of these 6 frequencies.
Rationale:
- 20 Hz and 100 Hz represent the low end of the frequency spectrum, where amplifiers can exhibit challenges in maintaining output power due to the low-frequency demands on the power supply and output stage.
- 1 kHz is a commonly used frequency to represent mid-range performance, where amplifiers typically perform well.
- 5 kHz, 10 kHz, and 20 kHz are used to ensure that the amplifier can handle higher frequencies and to evaluate any potential roll-off or distortion at the top end of the audio spectrum.
Procedure:
For each of these frequencies, the test would be conducted by:
- Gradually increasing the signal to the amplifier until it reaches the point of clipping (maximum undistorted output).
- Measuring and recording the output power at this point.
- Then, maintaining the continuous operation at this maximum output for 5 minutes while monitoring for any distortion, thermal issues, or power drop.
Thus, the
5-minute continuous operation should be performed for each of the
6 frequencies: 20 Hz, 100 Hz, 1 kHz, 5 kHz, 10 kHz, and 20 kHz.