? about amp output and input voltage

[husker77 10+ year member]

I have a general question about amplifier output. Let us say you have an amp that puts out 1000 watts. Now does it make a difference if you have 2 volts of input from your head unit or 8? Wouldn't you just have to raise the gain on the lower voltage input? You should be able to increase the gain more with the lower input voltage?

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[duanebro 10+ year member]

Yes, the higher voltage preout helps to reduce noise.

 

[husker77 10+ year member]

I understand that. I was wondering if a 1000 watt amp is a 1000 watt amp regardless of input voltage.

 

[fasfocus00 5,000+ posts]

I understand that. I was wondering if a 1000 watt amp is a 1000 watt amp regardless of input voltage.

are you saying that you can change the power output of an amplifier by increasing the pre-amp voltage?

 

[SplAffair 10+ year member]

yes 1000 watts is 1000 watts regardless. higher pre amp out puts just allow you to keep your gains set lower..

 

[quackhead 10+ year member]

I understand that. I was wondering if a 1000 watt amp is a 1000 watt amp regardless of input voltage.

a 1000 watt amp is a 1000 watt amp. Your gain is simply to match the input section of the amp to the source signal voltage at the sources' max listening level. Like you said in the OP, if your head puts out 2v max, set the gain for 2v. Too low a gain setting = loss in output, too high = clipping....if you have doubts, use a DMM.

 

[Flex68 10+ year member]

Wouldn't you just have to raise the gain on the lower voltage input? You should be able to increase the gain more with the lower input voltage?

Yes, and yes.

However, you are also amplifying any noise present on the lower voltage input BY those greater gain settings/factor when doing so.

Think of it like this:

2V inputs with a 48V amplifier output, and say you have 0.25V of noise. It is a x24 factor of amplification, so you get 1.75x24 = 42V clean signal, with 0.25x24 = 6V of noise.

Same amp, same gain setting, but with an 8V input. The noise is amplified only by a factor of x6, so you now have only 1.5V of noise with 46.5V clean signal.

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[husker77 10+ year member]

I was more wondering if you would not be getting less from your amp with lower output voltage. As in you would only be getting 700 from a 1000 watt capable amp if you only had the 2v input. I know about the noise and stuff.

 

[Flex68 10+ year member]

I was more wondering if you would not be getting less from your amp with lower input voltage.
One could kind of look at it that way....but you are getting whatever output it is capable of giving for the load impedance.

If it says it is 600WRMS at 4ohms, then you will get that power at that impedance.

As in you would only be getting 700 from a 1000 watt capable amp if you only had the 2v input. I know about the noise and stuff.

No, you're going to get the 1000 watts, regardless....just a heck of a lot more "efficient" with an 8V input signal (or even a 4V) than a 2V

jew knoe wha i shayin?

 

[husker77 10+ year member]

jew knoe wha i shayin?

yep