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<blockquote data-quote="Jonas84" data-source="post: 8820311" data-attributes="member: 687280">So in my bmw there is a little oem amp in the trunk that drives the oem subwoofers under driver and passenger seat. Decided to use a amp i know works lying around. Spliced the input wires to rca and hooked all up and used a separate battery to test out. Played Great. So i went on with installation. Checked ohm to speakers 2.5 on both. Checked ground and positive 0.2 and 0.1 loss in ohm. 0.2 loss Voltage to amp unloaded. But as soon as I put on the ignition and factory unit starts upp there is a constant humming? If i use external battery all is good. If I use rca to amp from ex my laptop but cars battery all is good. It just dont wanna play together... Why is it working with stock amp? One thing i noticed i have no ohm reading on either rca i spliced in from head unit, neither positive or negativ. On the widow i put ignition on and off.. You can clearly hear When i put it on, and how it picks upp all noice after ignition is off from all modules. The sound before is probably a electric disturbance When filming with my phone, because a ear cant hear that. [MEDIA=youtube]x5W76WK0SWI[/MEDIA]</blockquote>

[QUOTE="Jonas84, post: 8820311, member: 687280"] So in my bmw there is a little oem amp in the trunk that drives the oem subwoofers under driver and passenger seat. Decided to use a amp i know works lying around. Spliced the input wires to rca and hooked all up and used a separate battery to test out. Played Great. So i went on with installation. Checked ohm to speakers 2.5 on both. Checked ground and positive 0.2 and 0.1 loss in ohm. 0.2 loss Voltage to amp unloaded. But as soon as I put on the ignition and factory unit starts upp there is a constant humming? If i use external battery all is good. If I use rca to amp from ex my laptop but cars battery all is good. It just dont wanna play together... Why is it working with stock amp? One thing i noticed i have no ohm reading on either rca i spliced in from head unit, neither positive or negativ. On the widow i put ignition on and off.. You can clearly hear When i put it on, and how it picks upp all noice after ignition is off from all modules. The sound before is probably a electric disturbance When filming with my phone, because a ear cant hear that. [MEDIA=youtube]x5W76WK0SWI[/MEDIA] [/QUOTE]

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