Alphacool Eispumpe VPP755 Pump Review

Sound metering is not a difficult test to do. What is often difficult is to have a location where the background noise is as close to silence as possible to avoid interference with the readings you are taking. My normal bench locations (kitchen and laundry) are just not suitable, so a mini bench was set up in an isolated room and the testing done in the middle of the night to eliminate external noise interference.

The sound meter detects a dog barking 2 blocks away so it is pretty sensitive. The noise floor achieved in the test area was a tad under 33 decibels which is pretty darn silent, and just breathing normally is detectable on the meter, so holding of breath was required for each data point recorded.

Now….in a possible oversight in the testing procedure, the data recorded was taken on a loop running virtually unrestricted. It was pointed out to me after testing was complete that the pump noise will change when under load and therefore my data may not be a true representation of the pump in “normal operation”. The next time I am testing a pump I will re-test the VPP755 at the same time and update that data into this review. For now, the data and comparisons are as already mentioned, taken from the almost unrestricted simple loop pictured above.

The VPP755 sound data on it’s own is probably meaningless unless you are familiar with how noise is measured, but we will display the results here for those who are interested. For everyone else, we also will compare the VPP755 against an Aqua Computer D5 PWM.

First off, here is the raw data for the VPP755 recorded when it was running on the Sound Bench. Perhaps a missing column is the “Stage” it is operating at, but I am pretty sure you can work out which is which.

Normally we do our sound testing with the meter 12″ away from the noise source, however you may have noticed in the above table there are readings for both 1″ and 12″. The reason for this is that the D5 was noticeably louder compared to the VPP755 but the results were quite similar with the sound meter 12″ away. So both pumps were re-tested with the sound meter as close as possible (1″) which I think gave a better indication of the noise variance when plotted against each other.

Lets look firstly at just the VPP755 sound testing results before we look at comparisons. We have chosen to display Noise vs. Flow Rate, but it could have been Noise vs. PSI. We decided not to plot against RPM due to the erratic RPM readings as was discussed on the control section of the review.

It is worth mentioning the Stage 4 reading at 12″. To the ear it did seem a bit louder, but the 1″ reading did not really show this up.

Next – how is the noise level of the VPP755 in comparison to a D5 pump? Let’s find out by plotting the data of the VPP755 against a D5 PWM and see what we get. Before that though, I will just mention that the D5 PWM pump was tested after the VPP755 and the PWM setting was tuned to match the Flow Rate (GPM) of each of the VPP755’s stages, which matched exactly the pressure also.

To help make sense of the plots below, we’ll post the D5 PWM raw data table here as well as again placing the VPP755 data table.

First up is the 12″ readings. Here we see the VPP755’s loud stage 4 noise level being the outlier in noise performance. However at stage 5 the VPP is much quieter than the D5. Sometimes pumps and tops can have resonance issues with a setup which may or may not show up in the end user scenario.  If you do see resonance we would suggest adjusting the pump speed to avoid it.

Let’s now look at the results when the noise meter was placed just 1″ away from the pump:

These results favor the VPP far more than the 12″ measurements.  The VPP755 in fact seems far quieter than the D5 in 4 of the 5 flow rates tested at, and the other is virtually equal with each other and the ambient noise floor. It’s a pretty impressive set of results because the D5 is not a noisy pump anyway. However as the plots show the VPP755 appears much quieter for the same performance output.

Using the data from the sound testing, we can also plot out some power usage charts.

Again lets look at the VPP755 on it’s own first in a Power for Performance chart.
Now if we add the D5 PWM data onto the plot we clearly see that the VPP755 is using much less power than the D5 to achieve the same flow rate:

For the same output the VPP755 is clearly much more energy efficient. For the first 3 stages it uses less than half the power the D5 does to achieve the same output. The VPP wins on performance and energy efficiency which is quite astonishing. Another terrific result for the VPP755 to finish off with.

Next Up – Summary.