Question on gains, impedance, theory...

[Vmax911 10+ year member]

Here's the situation. Sub is Dual 2 ohm, which means is can be wired to either 1 or 4 ohms. Amp output is 200x1@4 ohm, 300x1@2 Ohm. Of course, I'd like to get the entire 300 Watts out of the amp.

300W @ 2ohm gives an output voltage of 24.5V. So I would set my gains to achieve this output voltage.

Now to get a theoretical 300W @ 1ohm, I would need an output voltage of 17.3V. So, if I turned the gain down to produce an output voltage of 17.3V, would the amp run at 1 ohm (though not specified at that level)? It would still have to dissipate the same amount of power, so thermally is should be ok(?), or am I missing something here?

(BTW, Sub is ID10, Amp is MTX 250D)

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[thch 10+ year member]

This assumes efficiency of the amplifier stays the same at high and low outputs. For a class AB or other linear amplifier, this is not true. efficiency drops at low output.

 

[quakerroatmeal 10+ year member]

It also depends if the amplifier is even 1ohm stable.

 

[req 5,000+ posts]

negative. you would still be running more current thru the amp, you would only be telling the amp that there is less of an imput signal.

still the same amount of amplification, just less signal to be amplified.

does not work the way you are thinking.

 

[helotaxi 5,000+ posts]

Also quite possible that you could be exceeding the current capacity of the ouput devices and *poof*.

 

[chevy_man 10+ year member]

Most likely you will overheat the amp and fry it with excess current. I've run my 2 channels that are 4ohm stable bridged down to 1 ohm before and they handled it, but I didn't notice any real change in output and they got hot fast.

Don't do it, just run it @4ohms till you can buy a bigger amp

 

[Vmax911 10+ year member]

Alrighty, thanks for setting me straight.