Alpine KTP-445U Power Pack.  Compact 4-Channel Car Amplifier — 45 Watts RMS X 4.   Add higher output and more dynamic response with this easy-to-install Universal Power Pack upgrade.
 
COMPACT
 
Compact size lets the KTP-445U fit where most amplifiers won’t. The KTP-445U comes equipped with the RCA and Auto-Sensing-Speaker level connectors and it fits behind the head unit in the dash of most vehicles. It's small and compact at only 7-7/16” x 1-1/2” x 2-1/2”. The size and flexible wires make the Power Pack an easy choice to save space.
 
INDEPENDENT FILTERS FOR REAR & FRONT INPUTS
 
High-Pass selectable switches for Front & Rear allow frequency filtering for a wide variety of speakers. Choose from full range to selectable range: 60Hz, 80Hz or 120Hz to fine-tune your crossover points.
 
CONFIGURABLE INPUTS
 
Need configurable options for Speaker-Level or RCA inputs to the Power Pack? On the bottom panel of the Power Pack there are selectable input options to accommodate Speaker-Level (0.5V-10V) or RCA (0.2V – 4V) inputs. Selectable 2 Channel and 4 Channel options give you the control to determine source inputs, and can eliminate the need for Y-adapters.
 
ACCESSIBLE FRONT & REAR GAINS
 
The Power Pack provides simple variable gain controls on the end panel for flexibility and a wide variety of system applications.
 
BEST SIGNAL-TO-NOISE CONTENDER IN ITS CLASS
 
In order to ensure that Alpine sound quality is heard at your ears, we’ve created a platform that offers an unbelievably low noise floor, taking extra care to ensure a clean signal path, with no extraneous interference. The end result: The Power Pack boasts 1 Watt Signal-to-Noise Ratio of 82dB or better.
 
TOTAL HARMONIC DISTORTION (THD+N) VS. FREQUENCY
 
Uniquely, the Power Pack distortion actually decreases at higher frequencies, resulting in a clean and clear signal where your ear is most sensitive to distortion. - < 0.03% THD+N @ 1W, 1% THD+N @ rated power.