The AP4-CH21 provides a 6-channel pre-amp output for use with aftermarket audio equipment. Using the full range, fixed level head unit output, in conjunction with CAN messages, the AP4-CH21 delivers a variable 5v RMS pre-amp output with fading, balance, equalization, and level control capabilities.

The module also retains all audio from other vehicle features such as factory navigation prompts, Bluetooth, and uConnect. A data controlled remote amplifier turn on wire is also provided by the AP4-CH21. When used in conjunction with the APA-TOS1 (sold separately), the module can provide a variable 2-channel fiber optic digital audio output (TOSLINK).

Important Notes:

• This interface is only compatible in vehicles equipped with a data-bus controlled premium sound system. To verify compatibility, look for an Alpine, Beats, or Harmon Kardon badge on the door speakers, center speaker, or factory subwoofer. If none of these brands are shown, check for the presence of a center speaker or subwoofer.
  
• The factory amplifier must remain connected, and in the vehicle after the AmpPRO has been installed.
  
• The remote output is rated at 2A of current. If more current is needed an external relay must be used.
  
• Channels 5 and 6 are non-fading outputs. The output level of channels 5 and 6 can be controlled using the supplied level control knob.
  
• The minimum volume level is set to 0 dB by default. If you are happy with this level in your particular application then additional adjustment is not required. Please refer to the Setup and Configuration section on page 2 for more details.
  
• The level control knob must be connected in order to manually adjust the minimum volume setting.
  
• No adjustments can be made manually using the programming button, or the factory SWC when the module is connected to a PC.

Shipping Policy

DBs Car Audio is proud to offer fast & free shipping on all items listed in our store!!

Shipping Methods and Transit Times

DBs Car Audio ships orders from our Kissimmee, Florida location. On occasion, orders will be fulfilled directly by the manufacturer or distributor in order to reduce the shipping time..

Order Tracking

Once an order has been shipped, we send our customers an email with the tracking number for the order. Click on the tracking link in the email to follow the location of the package on the carrier's website. If you did not receive a tracking number by email or need to confirm the tracking information, please contact call us at 1-800-927-9390

Signature Required

Due to the valuable contents of some shipments, DBs Car Audio will only require a signature upon delivery if the order is over $500. Such guidelines will not be overruled upon the customer's request. Please understand that this is a security measure taken by our Company to ensure the safe delivery of each package and guarantee excellent service. Many of our third-party shipping carriers and payment companies require signatures upon delivery to protect against fraud and theft. Customers may request a signature upon delivery by emailing us at dbscaraudiofl@gmail.com.

Shipping Policy Disclaimer

Delivery estimates do not apply to items shipped directly from the manufacturer, nor out-of-stock items. Some items that ship from the manufacturer can only be delivered to addresses within the 48 continental states.

Standard delivery time for domestic customers will average from 2-4 business days, but can take longer in some cases. Saturday, Sunday and national holidays are not considered business days for delivery purposes.

Our Shipping Guarantee applies only to shipments delayed due to our service failure. We will not guarantee shipments that are delayed due to an act of god (ex: weather), a catastrophic event, or failure by our delivery partners. Our guarantee is also voided if incorrect billing or shipping information is given and results in your order being delayed to its destination. Our guarantee is also void if no one is available to sign for shipment when delivery attempt is made if a signature is required.