>>Do the wireframe grilles cause much air turbulence and thus noise?
<br>Not at 5-7V, generally speaking. The stamped out grills do, however, and the bad ones also block some airflow; I always cut them out.
<br>BTW, while the Zalman has a sleeve bearing fan that is quieter than most, its behavior is not that different from other PSUs like the Enermax or the TruePowers that are thermistor equipped: if the thermistor gets hot enough, then the fan speeds up. In a low airflow but quiet and cool enough system, my Zalman sample started out quiet, but within 10 minutes the fan reached a much higher speed and became quite noisy. In contrast, in Kurt's system, which has much more airflow with 4 case fans (& is likely noisier), the Zalman PSU fan always stays at the minimum level.
<br>My TKPower PSU sample is marred by too much coil buzzing noise, and the case (which IS the heatsink) reaches ~50C before settling to equilibrium. I have not actually had it in a case yet, but my early assessment is that it will add a fair amount of heat to the system that MUST be transferred out in some way -- either by direct conduction through the case or some kind of airflow -- ie, fan. My ~GUESS~ is the unit is actually rated for 300W only with forced air cooling of some kind.
<br>But lots of people seem to have used it fanless, so until my review work is more complete, this is just conjecture. The <!-- BBCode Start --><A HREF="http://www.siliconacoustics.com/tkinstallation.html" TARGET="_blank">installation pages</A><!-- BBCode End --> at Silicon Audio tells lots.
<br>My general observastion after obsessing about PC noise for a couple of years is that no fan means cooling is ALWAYS a challenge & can be expensive to accomplish. A slow quiet fan, however, is sonically about the same as no fan for most applications and is much cooler, less complex & usually cheaper.
Mike Chin, SPCR Editor/Publisher
Support SPCR by buying your gear through these links: NCIX, Amazon and Newegg