Zalman ST300BLP "Black Box PSU Mod"

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Zalman powersupplies are some of the quietest around since the company focuses on what it calls the Computer Noise Prevention System with every product.

With the recent improvements Zalman have made on their latest model, the ZM300A-APF, we decided to revisit the older 300W ST300BLP and make a few changes of our own. When we first reviewed the ST300BLP we noticed the small internal vents of this single fan PSU and where a bit worried about good ventilation for the case.

Before the Mod

After the Mod

As part of the Black Box PSU Mod we wanted to increase airflow from the inside of the computer case and out through the powersupply. To this end, and to improve the overall look of a dull grey powersupply we came up with a series of practical modifications to create the " Black Box Power Supply."

The real goal here really was to improve the airflow of the powersupply which already had really good low noise characteristics and is pretty stealthy by itself. In doing this "upgrade" we also wanted to give the ST300BLP a more stylish look... and I think we achieved both points rather well.

Enter the Black Box Powersupply...

The first step in its construction was remove all the electronics out of the powersupply frame. Once that was done, we set out to cut away the frame which forms the grill which covering the exhaust fan.

It's commonly known that this kind of venting on a power supply does two not-so-great things; first it creates slightly louder noise levels because the grills apparently induce turbulence, and secondly they diminish the amount of air flowing through. Wire fan grills are an excellent solution as they cause almost no loss of airflow, but we wanted to do something a bit more unique.

The first obstacle was deciding on what kind of grill to use. Originally we looked around from some stainless steel screen but couldn't find any of the right diameter. Next up we tested some different kinds of window screen, but with the available materials out there neither the plastic nor the aluminum were really suitable for this kind of application.

There are a couple of options for high-tech fan grills if you want to go into the world of aerospace and mil-spec materials, but as cool as these things were, we just couldn't justify the expense for a sheet of titanium honeycomb.

In the end we found something which is easily accessible, really inexpensive, looks pretty funky, and is easy to work with. In fact this metal grill is so easy to work with all you need is a pair of scissors to cut it into the right shape. The black metal grill came from a standard Business Depot wire mesh paper tray which should set you back less then $8. The only other tools we used for this mod were a fret saw with spiral cut blade, metal file, 1/4" hole punch and a can of matt black spray paint.

Now that you know the details let's get started and go through how we made a regular Zalman power supply into the "Black Box."