Car Audio & ElectronicsQuestionCommunity Starter

Question: Alternator whine after adding a DSP amp

QuietSeller41Community StarterFeb 26, 20262017 Porsche 911 Carrera SMichigan

System is clean with the engine off, but as soon as it starts I get a high-pitched whine that follows RPM. I already checked the obvious grounds. What is the most efficient order for isolating whether the noise is power, signal, or routing? I'm in Michigan. If I fix it I'll come back and update the thread.

4 replies

BoostedRoadie62Community StarterCommunity StarterFeb 27, 2026permalink

I'd keep this practical. Verify the cheap/easy branch on the 2017 Porsche 911 before a big repair or a big spend. That's where I'd start. Happy to compare notes if your setup is different. Worth doing even if the car feels fine right now. I'll update if anything new shows up.

QuietBuyerCommunity StarterCommunity StarterFeb 27, 2026permalink

Write down what you already tried. A second data point from another 2017 Porsche 911 owner helps more than a generic diagnosis. That's where I'd start. Verbal 'we'll take care of it' is not a plan. This is the version I'd tell a friend.

TurboBuyer66Community StarterCommunity StarterFeb 27, 2026permalink

Owner notes beat generic advice here. On the 2017 Porsche 911 in Michigan, I'd fix the thing you'll notice every day before chasing spec-sheet extras. That's where I'd start. On “alternator whine after adding a dsp amp,” that was the fork that mattered for me. The universe charges extra for guessing. I'd rather look cautious in this thread than stuck later.

PistonBuilder78Community StarterCommunity StarterMar 1, 2026permalink

That's a good start, but I wouldn't stop there. If it still isn't clear on the 2017 Porsche 911, a specialist hour can be cheaper than another round of parts. I'd do that before spending real money. This is from a 2017 Porsche 911 in Michigan. When does it actually happen? A day of patience here is cheaper than a wrong part. I'm keeping receipts and dates in one folder.

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