Level Matching (setting gains) on a Stinger Amplifier

The gain dial on the Stinger amplifier must be level matched to the source it is connected to. For this tutorial we will use the Stinger MT-1000.1 amplifier which has an input sensitivity gain from 0.2 volts (counterclockwise) to 6 volts (clockwise).

1. The RCA output voltage from the source must be known.
   • If the Stinger amp is installed with an aftermarket radio, refer to the owner’s manual included with the radio.
   • If the Stinger amp is installed with a factory radio and an LOC (line out converter), the audio output voltage from the LOC must be measured with a test tone and a multimeter set for AC voltage.
   • If the Stinger amp is installed with an audio processor such as an Epicenter, the audio output voltage from the processor must be measured with a test tone and a multimeter set for AC voltage.
2. Once we know the output voltage from the source, we can now level-match the amp. Use these examples as a reference.
   • If the source voltage is 6 volts (ideal), turn the gain dial all the way counterclockwise.
   • If the source voltage is 3 volts, set the gain dial exactly in the middle.
   • If the source voltage is 0.2 volts, set the gain all the way clockwise. Note, a voltage this low denotes a problem, and you will most likely experience undesirable noise.

How to test the audio output voltage from different sources.

From a factory radio without a factory amplifier:

1. Disconnect all speakers from the radio to avoid being damaged.
2. Set the bass, mid and treble to default, in the middle at level 0. If there are any audio settings, set them all to default, flat. Ensure the fader and balance is in the middle.
3. Set the multimeter to AC voltage.
4. Connect the positive of the multimeter to the left front positive speaker wire.
5. Connect the negative of the multimeter to the left front negative speaker wire.
6. Download onto a USB flash drive, a 1khz test tone if installing an amp on highs, or a 40hz test tone if installing a subwoofer. These can be downloaded from the PAC Audio website.
7. Play the test tone and set the volume to 75%.
8. Take note of the voltage shown on the meter. It should be somewhere in the range of 3-10 volts.

From a factory radio with a factory amplifier:

1. Disconnect all speakers from the amplifier to avoid being damaged. If this cannot be done, then this test cannot be performed.
2. Set the bass, mid and treble to default, in the middle at level 0. If there are any audio settings, set them all to default, flat. Ensure the fader and balance is in the middle.
3. Set the multimeter to AC voltage.
4. Connect the positive of the multimeter to the left front positive speaker wire.
5. Connect the negative of the multimeter to the left front negative speaker wire.
6. Download onto a USB flash drive, a 1khz test tone if installing an amp on highs, or a 40hz test tone if installing a subwoofer. These can be downloaded from the PAC Audio website.
7. Play the test tone and set the volume to 75%.
8. Take note of the voltage shown on the meter. It should be somewhere in the range of 3-40 volts. Please make sure that the LOC or amplifier connected to the factory amp can handle the voltage shown on the meter.

From an audio processor or LOC (line out converter).

1. Disconnect the RCA jacks from the audio processor or LOC. Take note that if any speakers are still playing audio with the RCA jacks unplugged, they will need to be disconnected to avoid being damaged.
2. All audio settings must be default.
   • On the radio, set the bass, mid and treble to default, in the middle at level 0. If there are any audio settings, set them all to default, flat. Ensure the fader and balance is in the middle.
   • On the audio processor or LOC, set any sound effects such as a bass boost to disable or zero.
3. Set the multimeter to AC voltage.
4. Unplug the left RCA jack from the amplifier. Connect the positive lead from the multimeter to the tip of the RCA. Connect the negative lead from the multimeter to the base of the RCA.
5. Download onto a USB flash drive, a 1khz test tone if installing an amp on highs, or a 40hz test tone if installing a subwoofer. These can be downloaded from the PAC Audio website.
6. Play the test tone and set the volume to 75%.
7. Take note of the voltage shown on the meter. It should be somewhere in the range of 1-10 volts.