Purifi 1ET400A EVAL2 review
This test review was performed to comply with FTC: 16 CFR Part 432 (July 5, 2024) - Power Output Claims for Amplifiers Utilized in Home Entertainment Products
I tested the well known Purifi 1ET400A, EVAL2 mono board, installed by myself in a 2U x 19" modushop case. With a 3mm thick Al bottom panel.
1. Test conditions
The amplifier is supplied from Hypex SMPS400A180 main power supply, that allows to get about 200W/4ohm/1kHz/THD1% at best. It was tested with a 4ohm/400W resistor load mounted on a heatsink.
2. Pre-conditioning
First of all, the amplifier was pre-conditioned at 1/8 of the rated power. I estimated the rated power from the distortion measurement as 200W/4ohm/1kHz/THD1%. So, the pre-conditioning was at 1x 25W/4ohm for one hour, as requested by the FTC document. At the end of the pre-conditioning period, the amplifier case was cold with no hints of increased temperature of the case. There was no change in distortion during the test. The small images are clickable thumb nails.
3. Noise
Amplifier noise was measured with shorted input. The output noise voltage was 26 uV (20Hz - 20kHz) and 20 uV(A).
4. Frequency response
Frequency response was measured at 100W output power into 4ohm. There is no load dependence into higher impedance.
5. Power frequency response measured at 180W/4ohm, to 90kHz
Power frequency response covers whole audioband at 180W/4ohm with THD < 1%
6. Distortion
6.1. Distortion at 100W/4ohm
6.2. THD vs. level at 1kHz/4ohm stepped sine method 0.8s burst 0.5s interval
6.3. THD vs. frequency at rated power 180W and at 100W with measurement bandwidth 90kHz
So, I am declaring the rated power over 20Hz - 20kHz band to be 180W at THD <= 1%.
6.4. 5 minute sine test
The amplifier has passed 5 minute test at 180W/4ohm/1kHz with THD = 0.62%, being only slightly warmer at the end of the test period. The resistor load was, however, very very hot when the test was completed.
The amplifier distortion at 150W/4ohm is only THD = 0.0003%.
Pavel Macura 11/24/2024