Well, I'm looking at the schematic, and it appears that there are a couple things that could blow. C1 is the most likely, because it will see everything. It is an 85µF 100V non-polar cap. While the crossovers are quite different, when you get to the plats, all those early caps were upped to 150V. I'd go up to 150V for C1 and C4.
Likewise R1 is a 50W resistor and R6 is only 20W. R1 (0.5Ω) is probably implemented by a pair of 1Ω, 25W resistors in parallel. I'd probably make them each 50W. R6 is only a 20W (45Ω) resistor. I'd make that a 50W resistor. Probably a pair of 90Ω 25W resistors in parallel would do the job well.
Speaking of C1, you might think of changing that to something like THIS
It should sound like it isn't there!
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