Nice design ... but the thermal solution needs some work. It is very easy to crush a TPA3255 chip so spacers on the bolts between the PCB and Heat Spreader are needed to ensure both level and non-crushing assembly. Also I would suggest increasing the spreader to case contact area by perhaps 2 or 3 times. The 3255 is a relatively hot chip and case level passive cooling is not the best solution.
We haven’t had any thermal issues with the heat spreader as designed. Typical use case will be well under 100w of output and at 90% efficiency, the thermal output will be 10W. The spreader area is more than adequate for 10W and the large 5mm solid aluminum bottom panel can radiate probably 20W easily and has a silicone thermal pad used on CPU coolers for effective heat transfer and provides mechanical play to avoid crushing since the stack up height and stand-off height is such to avoid interference. It should be noted that in all testing situations, even full power stress testing, the chip never suffered a thermal shutdown.
@@XRKAudio Okay that's good news ... but the lack of spacers on those bolts is still concerning. If the assembly is even moderately unstable, the entire thing is at risk.
How is the chassis grounded? Power cable isn't connected (as it rightfully shouldn't). Not a good sign when an electrical advice video starts with SUCH a big question mark.
You can find out more about the DIY version of this amp here: www.diyaudio.com/community/threads/tpa3255-reference-design-class-d-amp-with-pffb.372379/ The chassis is a pre-prototype of the Warp-1 chassis used for development and testing.
