Sub-woofer amplifier installation

[Turbo4whl]

The installation instructions for a Sony amplifier states it should be mounted on a board. (not provided) Does anyone know why the board is necessary? Along with other understandable items like not near the heater or under the floor carpet and things like not to interfere with seat movement or impede the driver, all clear. Why is the board necessary??

 

[Swearbody]

Maybe To ward off ground loop interference. Otherwise you may have a ground loop through the chassis of the amp. Not the amp frying kind but instead the weird noise that oscillates with rpm.

 

[bucket]

Maybe just to guarantee a smooth rigid mounting surface, to promote airflow below it? As opposed to sitting on fluffy carpet?

 

[Swearbody]

From Crutchfield

• Do not bolt your amplifier directly to your car's metal chassis — that's inviting noise problems, like ground loops which hum or buzz. You could use rubber grommets around the mounting screws to isolate the case. Or you could mount the amp onto a wooden board or plastic panel and attach that to the car body.

 

[Swearbody]

One thing thats important note: Do not bolt or screw through both the amp mounts and mounting board as this will ground the amp to chassis through the screws. Screw the board down and then the amp to the board. Keep a few inches between the screws because a ground loop of that little resistance can travel through moisture in the air. This is why old butt connectors bundled together will cause feedback in the rain/winter

 

[Turbo4whl]

From Crutchfield

• Do not bolt your amplifier directly to your car's metal chassis — that's inviting noise problems, like ground loops which hum or buzz. You could use rubber grommets around the mounting screws to isolate the case. Or you could mount the amp onto a wooden board or plastic panel and attach that to the car body.

Thank you guys. Now I was thinking I don't want a board in the truck, I'll mount it on metal bracket. Of course that would not have been good. The next redundant question, why didn't the directions explain this?

 

[Swearbody]

Thank you guys. Now I was thinking I don't want a board in the truck, I'll mount it on metal bracket. Of course that would not have been good. The next redundant question, why didn't the directions explain this?

If they explained it they might have to tell you why. The only reason you have to do this with off the shelf amplifier is because they do not isolate the board. For just a few more dollars they can use a faraday shield/cage and completely isolate the board from interference.
The introduction of mosfet circuits ( metal oxide semiconductor field effect transistor ) causes the the cheaper amplifiers to buzz if not isolated. The "oxide" in the name refers to the isolation layer of the circuit.its gate is insulated from the channel by a thin oxide layer and this means that it can be damaged by static if it is not handled in the correct way, or the circuit does not protect it adequately.
I dont know if you ever took anything from the 80's apart and found the flat wire mesh surrounding the eprom chips. That was actually a faraday mesh used for interference. The higher end hand made amplifiers use a combination of the mesh and isolating foam to help mitigate the interference. To my knowledge they can be mounted to metal