Hypex UCD180HG class D amplifier module 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

Hypex UCD180HG is a class D mono amplifier module without a power supply. I am using a linear power supply with 2 x 32Vac/100VA transformer and a case with quite efficient heatsink.

1. Test conditions

The amplifier was tested loaded with a 4ohm/400W resistor load.

2. Pre-conditioning

First of all, the amplifier was pre-conditioned for one hour at 1/8 of the estimated rated power (initially 132W), i.e. at 16.5W/4ohm. At the end of the pre-conditioning period, the amplifier remained cold, with only slightly detectable rise of case temperature. There was almost no change in distortion during the test. It started with THD+N = 0.014% and finished with THD+N = 0.014%.

3. Power frequency response and distortion

Frequency response was measured at 132W output power into 4ohm, from 10Hz to 40kHz with measuring BW45kHz.

Power frequency response covers whole audioband at 132W/4ohm with THD < 1%.

4. Distortion

4.1. THD vs. level at 1kHz/4ohm stepped sine method 0.8s burst 0.5s interval with measuring BW90kHz

The amplifier distortion is below 1% at 137W/4ohm

4.2. THD vs. frequency at 132W/4ohm with measurement bandwidth 45kHz

4.3. 5 minute sine test

The amplifier THD+N was higher than 1% at 132W/4ohm/1kHz, after the pre-conditioning. The power was reduced until THD+N<1% and it happened at 122W. The rated power was derated to 122W/4ohm. The amplifier then passed the 5 minute test at 122W/4ohm/1kHz with final THD+N = 0.98%. The amplifier case and heatsink was only slightly warm at the end of the test.

Pavel Macura 12/4/2024