Fan noise is caused by the blades, so the nature of the motor turning them (AC or DC) is not a factor. It may be that a particular DC fan turns at slower rpm, and that would be quieter. Design of the blades, and whether the fan is small and runs fast, or larger and runs slow is what you care about. No practical fan is completely quiet.
I have a qsc amp, but it lives in the cellar (out of the listening room). That is the only perfect solution.
You might want to hide the fact (from your audiophile buddies) that you use a pro-sound amp. If so, and if the cellar is not an option, consider putting the amp in a soundproof box of some kind, with some provision for ventilation through internal sound-baffled ducts up and down (like a chimney). The amp has overtemperature protection, so you won't do damage.
I have a qsc amp, but it lives in the cellar (out of the listening room). That is the only perfect solution.
You might want to hide the fact (from your audiophile buddies) that you use a pro-sound amp. If so, and if the cellar is not an option, consider putting the amp in a soundproof box of some kind, with some provision for ventilation through internal sound-baffled ducts up and down (like a chimney). The amp has overtemperature protection, so you won't do damage.