A commercial mixer amp in a tiny box. By gut-feeling I don't like the relative absence of air cooling and would like some justification to increase the , at least output vent size - there is space for much larger holes, but not necessarily aesthetic.
2 switch mode power supplies plus 2 100W rms D class amps and an 8 channel mixer in a box only 10x6x2.5 inches. The 2 SMPS are "cooled " by a 12V 40mm fan blowing the internal air, not positioned near any inlets, over the heatsinks. Inlet vents , if all 1/4 inch sockets should have tight fitting plugs in all of them, are 30 x 2mm diameter holes. The other fan is 12V, 50mm fan that pulls air over the 2 amps and exhausts directly to the outside but via 8 small slots .44 inch long and .08 inch wide that seriously restricts the flow out. The owner reports the exhaust as being hot rather than warm and i've taken some measurements with thermometer etc with relatively low continuous sine to external dummy load. I intend giving the owner a thermometer to take some readings in normal use over an hour of guitar performance. I fixed, with sealing tape, a large diameter tube around the exhaust area to direct into a very thin plastic rubbish sack, with no perforations, to time and measure the air flow until about 2/3 full and holding the floppy bag up as well so I'm assuming relatively little back pressure or whatever the term is. I did not think, while inside , to note any amp rating as well as 12V, nor make and model, but generally 50 mm fans would be about 8 to 18 cfm cubic feet per minute. But from my calculation over 3 minutes then the flow rate was only 0.78 cfm. This amp is designed so it can be transported and used , recessed into one of the speakers, so not much heat lost through the walls of the box I would have thought, I'm advising, interim, for the owner to use the amp removed from the speaker. Any comments on the adequacy of venting?- posted
16 years ago