Ok, I did some experimenting today. The pinout for the fans looking at it from the end of the connector looks like this:
| 1 2 3 4 |
where the top spikes are the key tabs on the connector. Pin 1 is ground, pin 2 is 12V power, pin 3 is the Tach sens., and pin 4 is the control pin. I supplied 12V to pin 2 and slowly increased the voltage to pin 4 up to 12V without frying the fan at all. This means that if you make a connector that is exactly the same as a 3 pin fan (a normal 3 pin to 4 pin molex adapter) and connect it to the PSU molex connector (these fans draw a lot of current so don't power it from the motherboard) and run two more wires to the tach and voltage wire from the motherboard to the tach and control pins of the fan, you would have control.
That being said, these fans run really fast at a full 12V and even down to 5-6V and are very loud. That's where the ULNA adapter comes in. These are simply just a 3 pin extension with a resistor inline on the power wire. There are two adapters that came with the fan and one is 150 ohm, the other is 50 ohm. These will reduce the 12V output of the motherboard header to about 5-6V or 3-4V depending on the adapter. This is a much more reasonable speed.
They are very quiet up until about 1000-1100 RPM (about 2.5V on the control line) but the specs for these fans say they are 3300 RPM fans. They move 130 CFM at 44 dB, but utilize .75A each. I also hooked a multimeter up to them to measure current draw and found that they draw that current on the control line. The problem is that the motherboard just can't handle that much current. I've also measured the current on the 12V power wire (pin 2 in the above description) and found they use about .2A on that line, but reducing the voltage to pin 2 doesn't change the speed of the fan.
My conclusion seems to be that these will just have to be manually controlled. I built a LM117T-ADJ circuit with a potentiometer that varies the voltage between 2.5V and 5V which does a decent job of controlling them. I used the output of the circuit to go to the control wire. This lets the fan range from 800 RPM to 1100 RPM and at all ranges move lots of air at near silent operation. I personally wouldn't spend $40-$50 on these as they are too difficult to control, but these are basically the same fan: http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=36_403&products_id=24322
for $16. They have almost the same exact model number (last four digits are different), but when I compared them to the specs here: http://www.excesssolutions.com/cgi-bin/category.cgi?item=ES5358
, they're basically the same. The difference is that the non-Apple fans are easier to control.