3 Pin PWM Fans on vent booster

[Poetart]

Bought one of these and worked great for my office:

but

The fans on it have some coil / bearing whine that I can not stand past 3/4 out of 10. Got a replacement that was a bit better but still had the whine. 
So decided to swap the fans in my office and see how it goes and leave the quieter one in the kitchen by the refrigerator as the other sounds sorta block it out.

When I went to swap the fans its a 3 pin PWM with a different (Than PC) fan connector. I got a Noctua A9-FLX 92mm that I can get working but wondering if a PWM fan would work and if that would be a better options as I loose speed control on this now. 

From what I can tell, looks like its not grounded?

Looking for someone with a bit better fan / electronic knowledge to help me understand what I am looking at here. 

 

[Electronics Wizardy]

3 minutes ago, Killerclan117 said:

From what I can tell, looks like its not grounded?

It looks like it doesn't have a speed monitor. Since it has a pwm output, Id get the 4pin fans, then connect the + - and pwm pins in, and forget about the speed monitor pin, as it doesn't appear to be using that pin here.

 

 

[Poetart]

1 minute ago, Electronics Wizardy said:

It looks like it doesn't have a speed monitor. Since it has a pwm output, Id get the 4pin fans, then connect the + - and pwm pins in, and forget about the speed monitor pin, as it doesn't appear to be using that pin here.

 

 

You just saved me a lot of time tinkering on this thing! Thanks. Ordered two A9-PWM's and will test out tomorrow.