I'm using a normal 80mm computer case fan (12V@0,02A) with a 7.5V AC adapter and I guarantee you that it is quite noiseless.
I'm just waiting for a power adapter for my hub and I'll put all my BE's next to the Ants in the same hub, and then, put them on a "shoe box" to properly manage the heat and create some tunneling to improve airflow and have it neatly arranged.
But let me ask you: besides the noise, have you already tried to use 0981 frequency and a fan? even for one hour.
That way you'd check if it is some heat issue or not.
And you might have some USB Hub lying around that you could use instead the extension cable?
These are just some ideas to troubleshoot your problem.
Thanks for your advice, I will have a look into the hub and fan options, I dont have either to hand though. I just liked what chromosoma had done with his set up on top of that ali heat sink, I could acheive this quite easily and cheaply so I thought that would be the best way to go. I've been looking into the different thicknesses of thermal pads but can't really find any solid information on what thickness to go for.
I've been running it for about 25 minutes on the 4F02 setting, it's getting 4.8% HW so far.
I will try relocating it using the extension cable when that arrives and see about getting hold of a fan to see if I can improve things. Thanks again