Someone on r/hometheater posted a diagram of two USB fans sat beside a Denon S770H, plugged into the receiver's own USB port, meant to pull hot air out sideways. There is apparently plenty of room either side but only an inch to an inch and a half above the unit. I have been in exactly that spot with a cabinet built by someone who had clearly never owned an amplifier.
Two things I would think through before buying fans. First, receivers dump heat upward. It leaves through the top plate and the top vents, so an inch of clearance is the actual problem, and fans at the sides are moving air past the case rather than through it. If you are going to fit fans, place them so they draw air off the top surface and out of the opening, not across the front of the shelf where it feels productive and does nothing.
Second, that USB port. I would not assume it behaves the way you want. On plenty of receivers it exists for a thumb drive, and it can cut or change state in standby or when the unit switches source. A fan that quietly stops when you change input is worse than no fan, because you stop thinking about it. A cheap USB brick behind the rack costs almost nothing and always runs.
The free fix deserves a look first though: can that shelf come out, or can the receiver move to the top of the stack? Every fan setup I have owned was a workaround for a shelf I could have unscrewed.
Has anyone actually compared their receiver's own temperature readout before and after fitting fans? I have only ever gone by how hot the top plate feels, which is not evidence.
Two things I would think through before buying fans. First, receivers dump heat upward. It leaves through the top plate and the top vents, so an inch of clearance is the actual problem, and fans at the sides are moving air past the case rather than through it. If you are going to fit fans, place them so they draw air off the top surface and out of the opening, not across the front of the shelf where it feels productive and does nothing.
Second, that USB port. I would not assume it behaves the way you want. On plenty of receivers it exists for a thumb drive, and it can cut or change state in standby or when the unit switches source. A fan that quietly stops when you change input is worse than no fan, because you stop thinking about it. A cheap USB brick behind the rack costs almost nothing and always runs.
The free fix deserves a look first though: can that shelf come out, or can the receiver move to the top of the stack? Every fan setup I have owned was a workaround for a shelf I could have unscrewed.
Has anyone actually compared their receiver's own temperature readout before and after fitting fans? I have only ever gone by how hot the top plate feels, which is not evidence.
