fjord
Hello, I checked your vehicle, the Yukon XL Denali, which comes with 9 Bose speakers with approximately 2Ω impedance. Our head unit uses an onboard TDA7850 amplifier, designed mainly for 4Ω speaker output.
Based on your feedback:
The hiss only occurs when playing music and stops when muted or paused
Noise appears when RCA cables are connected and disappears when disconnected
Grounding or firmware updates did not resolve the issue
Considering the head unit output and the factory Bose amp/speakers, the problem is very likely due to impedance mismatch. The TDA7850 output is designed for 4Ω, while the Bose amp and speakers are 2Ω, which may cause improper amp input processing and result in constant hiss.
Before we provide the final solution, you can try the following temporary troubleshooting steps:
Check grounding: Ensure the head unit and Bose amp are properly grounded to avoid ground loops;
Use a ground loop isolator: Install it on the RCA cables to see if it reduces the hiss;
Disconnect other external audio devices to rule out interference;
Adjust volume and signal source to observe if the hiss changes.
We are working on the best solution to ensure compatibility between the head unit output and the factory Bose amp without replacing the original speakers. Thank you for your patience; we will provide the solution as soon as possible.
