Where this fits in the build
This is a system-control or DSP component. The correct choice depends on the signal path, channel count, routing, retained features and the rest of the amplifier and speaker plan.
Description
PAC AP4-GM81 AmpPRO 4 2023+ GM Bose A2B Amplifier Integration
GM changed the Bose architecture again with A2B. GM81 is the AmpPRO interface for the supported newer vehicles where the factory Bose amplifier is part of that digital network and needs to be replaced, not worked around.
AP4-GM81 extracts the audio from the A2B system and provides front, rear and non-fading/subwoofer outputs for the aftermarket DSP or amplifiers while keeping the factory radio and supported vehicle audio functions in place. The factory Bose amplifier is disconnected during the install, and PAC supplies the harnessing needed to hand the speaker side over to the new system.
That gives us a cleaner starting point than taking signal after the Bose amplifier and trying to undo its processing. The factory interface stays familiar to the customer; the aftermarket system gets to control the part of the audio chain we are actually upgrading.
GM61, GM71 and GM81 Solve Three Different GM Systems
GM61 is the older MOST50 Bose architecture and keeps the supported factory amplifier connected. GM71 moves to Ethernet audio and replaces the factory amplifier. GM81 moves again to A2B and also replaces the factory amplifier.
Those are architectural differences, not product generations where the newest part automatically wins. A Bose badge or a 2023+ model year is not enough to choose GM81. The actual factory audio network has to match PAC’s application.
Optical Is Already Part of the Interface
GM81 provides analog preamp outputs up to 5V RMS, but it also includes a variable two-channel TOSLINK optical output. If the DSP accepts optical, the digital handoff is already available from the integration interface—there is no need to add APA-TOS1 separately.
Factory volume, fade, balance, bass, mid and treble remain integrated in supported applications. PAC also retains supported warning chimes, navigation prompts, Bluetooth audio and telematics audio, so replacing the factory amplifier does not mean giving up the factory-side functions that still matter.
Manufacturer Specifications
- Model: AP4-GM81
- Product type: PAC AmpPRO 4 A2B amplifier integration interface
- Application: Select 2023+ General Motors vehicles with compatible Bose A2B factory-amplified audio
- Signal extraction: Vehicle digital A2B architecture
- Factory amplifier: Disconnected in supported GM81 installations
- Speaker connection: Factory-amplifier replacement harnessing included
- Analog outputs: Front, rear and non-fading/subwoofer preamp outputs
- Maximum analog output: 5V RMS
- Digital output: Variable two-channel TOSLINK optical output included
- Factory controls retained: Volume, fade, balance, bass, mid and treble in supported applications
- Supported retained audio: Warning chimes, navigation prompts, Bluetooth audio and telematics audio
- Sub-level control: Included remote controller
Manufacturer: PAC