Factory Amp Breakout Box
Many 00'-01' Impala owners complained about the lack of response from the amp located in the trunk. One solution has been to bypass the amp or the harness off and installing an aftermarket one. Rather than cutting the harness, Richard tore apart the factory amp and used the amp's connector to build a break out box.
Richard says that the internal electronics of the amp are not impressive and probably doesn't put out more power than the head unit itself. This mod requires some electrical background and the following pin out diagram:
Richard sent another photo and additional info:
1) The white wire connected to pin A5 is 'delayed accessory power' from the deck, which is what is needed to control the power amp on/off. It actually seemed to be delayed a further 20 seconds after the deck turned off, but that should not matter. +12 volts on, 0 volts when off. I have added an additional terminal to the modified amp for this function. I have a new pic that shows the red terminal in the foreground and the jumpers for the amp bypass.
2) My testing has shown that the deck does not sense the amp presence and does not switch to a 'low-level' mode. It does not seem to care if the amp is there or not. Pin A6 seems to float at +6 volts when the amp is not present and goes to 0 volts when the amp is present, however the deck does not change is output.
Richard does it again. He's figured out how to force the radio to output a line level signal when you remove the amp from the circuit. With this mod, you can install an aftermarket amp without using line level converters.
"You are correct the deck does reduce power when it senses the amp. I was under the incorrect assumption that the amp would not be seen as present if it was powered off.
"I have added a presence switch to the prototype as per the pic.
"When the deck senses the amp, it reduces power, BUT it also disables the loudness function, which boosts the bass at low volumes. This is the reason the premium system sounds so poor in contrast to the base unit."