Wiring/Repurposing a simple "knob style" RPM fan speed controller

[Jet3030]

Hey guys. I have a PWM fan that I have wired up direct to power to use as a case fan. As you know, the RPM's are running at full throttle now. I would like to repurpose an old Thermaltake knob fan controller to get the speed under control, but had some questions. Can I just wire the knob in line with the red power going to the fan? Does the knob just act as an adjustable resister? Or does it need to be hooked up to an additional component to adjust properly? The Thermaltake part is a PCIe slot controller that was part of an old water cooling system. It originally controlled the radiator fan, but that fan has a dedicated plug for it separate from the fan power wire. I would just use that fan, but it's 120mm. The one I want to use is for a SFF system that the original fan won't fit in. Thank you in advance for any information or advice that you give!

 

[Jet3030]

So I got impatient and just wired it directly in line with the red wire on the fan power adapter and it works perfect. It even turns the fan off completely when I dial it down all the way. I guess it wasn't an interesting enough question to get input on. Thanks anyway forum members ...