Purifi 1ET400A test with linear PSU
I was curious to test the 1ET400A module with linear power supply and to test it to comply with the FTC (05/2024) rule.
My linear power supply gives 2 x 61Vdc to Purifi module at idle and 2 x 56Vdc at THD1% module power. The test load was 8ohm.
1. THD check in the linear area
We can see that the distortion is very low and we have no issues with mains spuriae, despite the fact that conventional design linear power supply is used.
2. Power for THD1%
THD1% is for 160W/8ohm. Interestingly, the rise of noise floor for THD1% is lower than in case when SMPS was used (another thread).
3. THD vs. frequency and THD1% vs. frequency
At 160W, the amp keeps THD near 1% up to 4kHz. Then, the distortion goes down to much lower numbers. I have already described this behaviour of the Purifi module, and it is independent of the power supply used.
Plots for 130W and 103W are shown as well. Please note rise of LF distortion in the 130W plot. (maybe familiar to @Sokel )
4. THD vs. level
Please note that the highest power achieved is at highest frequency (10kHz here).
5. 5 minute test at 160W/8ohm/1kHz
The amplifier has passed the 5 minute test easily, staying cold, and with a negligible rise of distortion. The power supply voltage at 160W/8ohm was 2 x 56Vdc.
I was curious to test the 1ET400A module with linear power supply and to test it to comply with the FTC (05/2024) rule.
My linear power supply gives 2 x 61Vdc to Purifi module at idle and 2 x 56Vdc at THD1% module power. The test load was 8ohm.
1. THD check in the linear area
We can see that the distortion is very low and we have no issues with mains spuriae, despite the fact that conventional design linear power supply is used.
2. Power for THD1%
THD1% is for 160W/8ohm. Interestingly, the rise of noise floor for THD1% is lower than in case when SMPS was used (another thread).
3. THD vs. frequency and THD1% vs. frequency
At 160W, the amp keeps THD near 1% up to 4kHz. Then, the distortion goes down to much lower numbers. I have already described this behaviour of the Purifi module, and it is independent of the power supply used.
Plots for 130W and 103W are shown as well. Please note rise of LF distortion in the 130W plot. (maybe familiar to @Sokel )
4. THD vs. level
Please note that the highest power achieved is at highest frequency (10kHz here).
5. 5 minute test at 160W/8ohm/1kHz
The amplifier has passed the 5 minute test easily, staying cold, and with a negligible rise of distortion. The power supply voltage at 160W/8ohm was 2 x 56Vdc.
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