Hey all,
I don't care if you think Bose sucks. You need to take a peek at this mass manufactured multi-channel amp. In my 30 years in electronics development this one has captured my attention. They have optimized their design to the point where there they supply a decent amp with only a few manufacturing steps. This does not impact quality but significantly reduces manufacturing cost. If aftermarket brands could follow these design cues they could drastically reduce their cost to us. This is not a praise to Bose. It is just showing you what can be done with decent design practice.
Amp mounted in car
Extracted
To the left is a MOST25 optical communications buss connector from the head unit. To the right are the speakers out. The center connector is not connected. Maybe used for factory end of line test?
Variable speed intake fan to cool what's inside. I've never noticed fan noise from this amp even with the access cover taken off the vehicle. They must have a good strategy to only ramp up fan speed as the amp gets hotter.
Bottom plate. I can see stamping's to press against cooling points and holes to ventilate heat.
Back plate removed. Notice the rectangular contact patches on the PCB where the bottom plate touches to facilitate cooling. Notice the EMI shield over 1/2 the board. This is to minimize interference between high speed digital circuits and the sensitive analog circuitry.
Main board pulled out. Just like the sub-woofer amplifier this board uses Texas Instuments audio amplifier IC's. This is a 9 channel amplifier. The IC's have 2 channels each. The IC channels can be bridged for higher output. Heat sink contact points revealed. The 5 points with heat sink compound dissipate more power. This is most likely for mid-bass and maybe mid-range channels. There is one point with a thermal pad. Chances are this IC does not consume as much power and requires less cooling. Perhaps this supplies tweeters? Note, there is an even larger EMI shield on this side of the board.