Phanteks AMP Series 750W Power Supply Review

Advanced Transient Response Tests

For details about our transient response testing, please click here.

In the real world, power supplies are always working with loads that change. It's of immense importance, then, for the PSU to keep its rails within the ATX specification's defined ranges. The smaller the deviations, the more stable your PC will be with less stress applied to its components. 

We should note that the ATX spec requires capacitive loading during the transient rests, but in our methodology, we also choose to apply a worst case scenario with no additional capacitance on the rails. 

Advanced Transient Response at 20% – 200ms

Advanced Transient Response at 20% – 20ms

Advanced Transient Response at 20% – 1ms

Advanced Transient Response at 50% – 200ms

Advanced Transient Response at 50% – 20ms

Advanced Transient Response at 50% – 1ms

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Results 25-29: Transient Response

The transient response is good on the +12V and 5V rails. There is room for improvement on the minor rails, though, especially at 3.3V, where the PSU failed in most tests that we conducted. 

Turn-On Transient Tests

In the next set of tests, we measure the PSU's response in simpler transient load scenarios—during its power-on phase. Ideally, we don't want to see any voltage overshoots or spikes since those put a lot of stress on the DC-DC converters of installed components.

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Turn-On Transient Response Scope Shots

The +12V rail requires some time to reach its nominal voltage, which is nothing to worry about. 

Power Supply Timing Tests

There are several signals generated by the power supply, which need to be within specified, by the ATX spec, ranges. If they are not, there can be compatibility issues with other system parts, especially mainboards. From year 2020, the PSU's Power-on time (T1) has to be lower than 150ms and the PWR_OK delay (T3) from 100 to 150ms.

The PWR_OK delay is out of the 100-150ms region, so the PSU does not support the alternative sleep mode, which is required by the ATX spec from 2020. On the other hand, the power-on time is within the required range, at 80ms. 

Ripple Measurements

Ripple represent the AC fluctuations (periodic) and noise (random) found in the PSU's DC rails. This phenomenon significantly decreases the capacitors' lifespan because it causes them to run hotter. A 10-degree Celsius increase can cut into a cap's useful life by 50%. Ripple also plays an important role in overall system stability, especially when overclocking is involved.

The ripple limits, according to the ATX specification, are 120mV (+12V) and 50mV (5V, 3.3V, and 5VSB).

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Results 30-33: Ripple Suppression

The ripple suppression is not up to the extremely high levels that the Corsair RMx unit achieves, but still, it is satisfactory. 

Ripple At Full Load

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Ripple Full Load Scope Shots

Ripple At 110% Load

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Ripple 110% Load Scope Shots

Ripple At Cross-Load 1

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Ripple CL1 Load Scope Shots

Ripple At Cross-Load 2

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Ripple CL2 Load Scope Shots

EMC Pre-Compliance Testing – Average & Quasi-Peak EMI Detector Results

Electromagnetic Compatibility (EMC) is the ability of a device to operate properly in its environment without disrupting the proper operation of other nearby devices.

Electromagnetic Interference (EMI) stands for the electromagnetic energy a device emits, and it can cause problems in other nearby devices if too high. For example, it can be the cause of increased static noise in your headphones or/and speakers.

The QP detector caught several spurs that go over the limits, in the 503-581 kHz range. 

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