Repaired Presonus HP4 v1 Headphone/Monitor Amp
My very useful Presonus HP4 v1 headphone amp fried last Fall. I found another on eBay for not too much, but I hung onto the old one. Turns out they’re full of this quad amp IC, MC33079P, and one on the input stage failed. The chip is obsolete, but I replaced it with an MC33079PG that seems to be the same. Or at least compatible. The hardest part was un-soldering a 14-pin IC without destroying the PC board. I added…