| My experience - fans are rated by size and airflow. Power might be included as well so you can size the power supplies but for a replacement fan, you care about size and airflow. Specs include noise ratings but its tough to compare them between manufacturers because there's no standard and everyone wants to appear to be quieter than the competition.
That said, noise and air flow generally go hand in hand so for the same airflow (usually measured in cubic feet per minute or the metric equivalent for you european types), you probably won't get any quieter going with an alternative manufacturer. If you go with a quieter fan, you're likely to get one with lower airflow which will cause the electronics to get less cooling. Less cooling could lead to heat damage of the power transistors in your amp, then again, it might not depending on how much design tolerance there is.
I suspect the engineers allow high margins for cooling needs in part because fans age, in part because cooling fins get dirty, and in part because amps need to survive in warm environments.
If your fan is causing noise in your signal chain (I've had this happen), a new fan should cure the problem (it did in my case). As contacts wear, the EMI from the fan will increase. Same for excess mechanical noise due to bearing wear or fan blade wear. If you just want to reduce the flow noise in the fan, you're probably going to have to go to a lower flow rate. If you do, try not to go too low on the flow rate and check the temp of the amp often when you run it the first couple of times. It's a risk to the electronics and without knowing the particulars or having a lot of experience with your specific equipment, it is impossible to know whether or not you'll have an overheating problem with a lower flow rate fan.
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Clubs: BTB 118, Ibanez 689, 5-string 436, P&W 820, Lefties who play Rightie 157
BTB675, EDB605, GSR200,
Peavey BAM 210, 115BX BW, TVX 410, Mark VIII XP
Last edited by Rob22315 : 09-07-2011 at 03:07 PM.
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