Post by
Broadfield »
https://forums.nicoclub.com/broadfield-u46569.html
Fri Sep 14, 2007 2:07 pm
That's a good educated question, the kind I like! The reason for high voltage outputs is simple: to keep the gains on your amplifier lower. Which in turn will keep noise down if you have any. If you don't naturally have noise in your system, then a lower voltage pre-out isn't going to add any more noise, and a higher voltage pre-out isn't really going to benefit you. You want to stay away from .5V or 1V pre-outs. Anything 2V or higher is plenty!
Your amplifier receives a low voltage signal from the head unit and increases it to a higher voltage (and current). This voltage is music. The problem is, electrical noise may be present, and that too will be amplified resulting in alternator whine, ignition noise, etc. If you turn the amplifier gains down, the electrical noise is amplified less, but so is the music. The higher voltage head units put out more so you can still get satisfactory volume with the power amp gains reduced, thus the system sound to noise ratio is improved!
If you do not have random electrical noise coming out of your speakers, then higher voltage head units will not make any difference for your particular installation.
The test for this is to turn the radio all the way down and listen to the speakers with the engine running. If you hear objectionable noises, then turn your amp gains down. If you then cannot get enough volume out of your system, even with the head unit turned all the way up, consider a head unit with higher output voltage so you can keep the amp gains low enough to stop the noise.
Of course with a proper install and quality cables, you really shouldn't have any noise at all!