Reversing amplifier airflow

Having two amps in the same rack where one cools front-to-back & the other back-to-front shouldn't really be an issue unless the rack is sat somewhere with very poor airflow around it to begin with.

odc04r wrote: No way, that can be a massive problem on normal stages. Have seen it happen, you just end up with a cycle of increasingly warm air.

 

if theres the room in the front of the case it self.... i would at least double up on fans if your gonna turn them round to draw air out the back. i.e put another pair at the front blowing onto the 'sinks and the rears removing what they can from the case.

tomr_29 wrote: If the rack is in a corner or close in behind the stack I can see it being a problem, hence why I want to have everything going the same way. I'm now thinking it'll be easier to modify the other amp (which is well out of warranty) using some folded plastic inserts to tunnel the air from the heatsinks to the fans (see yellow arrows below) with the fans reversed to become exhausts.

This design has more transistors close to the fans and less of them the farthest away from the fans. Fresh air at the beginning of the heatsink has more capacity to take up heat. Farther down the heatsink the air is already warmer with less heat dissipating capacity. Now in some amplifiers, you can swap amp modules from left to right and/or upside down and still have all connectors in place with some minor cable rerouting, cut and replace a few tie-wraps or so. If possible with this particular amp, I would place the fans in front, blowing front to back, so you have the same setup it has now, but flow reversed and heatsinks placed the right way in combination with the fans.
Just flipping the fans around, could work on a not to heavy charged amplifier (8 Ohm loads, compression drivers,..), but even so, you'll never know in what kind of environment they sometimes have to perform (sun shining full on your racks, real warm weather, confined spaces,...).

And Macrotechs (except 5000) vent out of the sides so neither front or back.

Most of the versions of amp in the picture have the air drawn out of the back.
Bear in mind those fans will be variable speed so consider what bigger or more fans might do to the vari-speed circuit. Also, see where the bias temp compensation is sensed in case your modified airflow upsets the bias under differing temperatures...not that it should, too much