im looking to add a fans to a few amps ive tried a few different circuits but cant keep the amp from picking up the hum of fan. any ideas?
smaller pc fans. i tried to get it from the b+ of the amp with a switch . but then i was thinking i should build a small power supply to run fans.
Brushless fans (PC fans) rarely cause noise. You could try inserting a low value resistor (1 ohm) in the power line for the fan and then connecting a 1000uf cap across the fan terminals.
IME,Brushless fans tend to inject a lot of noise back into the power rail.
I usually do like Perry suggested,10-ohms or so(helps slow the fan a bit,so it runs quieter too),and a big cap. That is usually enough to knock any electrical noise down a good ways,as well as knocking down the physical noise a tad.
I usually do like Perry suggested,10-ohms or so(helps slow the fan a bit,so it runs quieter too),and a big cap. That is usually enough to knock any electrical noise down a good ways,as well as knocking down the physical noise a tad.
I would set-up a separate PS for the fans simple enough.....chasing the noise on your B+ might be more trouble than it's worth. Run the fans at half power to 2/3rds' to keep the physical noise down......at the lower power your at the noise floor (Can't hear at all!!)
_____________________________________________________Rick.........
_____________________________________________________Rick.........
what we have on motors in the trucks at work are chokes. i think they have the caps, too, but the chokes are real obvious. kind of like a high-pass shunt/low-pass motor.
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