Random impedance question

[Staynlean 10+ year member]

Amplifier is a RF 750-1D:

Rated Power

250 Watts x 1 @ 4-Ohm

500 Watts x 1 @ 2-Ohm

750 Watts x 1 @ 1-Ohm

If I were to present an 8 ohm load to it, why kind of power would I see? And, is it ok to do so?

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[NASTY08IMPALA 5,000+ posts]

Amplifier is a RF 750-1D:
Rated Power

250 Watts x 1 @ 4-Ohm

500 Watts x 1 @ 2-Ohm

750 Watts x 1 @ 1-Ohm

If I were to present an 8 ohm load to it, why kind of power would I see? And, is it ok to do so?

It would put out abt 125rms..and yes its fine

 

[akillj 10+ year member]

Perfectly fine to put more resistance, will just put out less power. In theory, it should be ~250 / 2 = 125wrms. Give or take some.

 

[Staynlean 10+ year member]

Thanks guys

 

[gstokes]

Amplifier is a RF 750-1D:
Rated Power

250 Watts x 1 @ 4-Ohm

500 Watts x 1 @ 2-Ohm

750 Watts x 1 @ 1-Ohm

If I were to present an 8 ohm load to it, why kind of power would I see? And, is it ok to do so?

It never hurts the amplifier to present it with more impedance than it's rated for, only when we present the amplifier with less impedance than it's rated for do we run the risk of damaging the amplifier.

I will attempt to explain why: We know that voltage and current are inversely proportional IF the resistance is constant, we also know that current and resistance are inversely proportional IF the voltage is constant so if the voltage is remaining the same but the resistance in the speaker circuit aka (load impedance) is dropping then the current must be rising, with increased current comes increased heat and the amplifier will only get so hot before it goes into thermal overload and shuts down.

That's why some amplifiers are only rated "stable" to 2 ohms while others are rated stable to 1 ohm, excessive current aka heat is what causes the instability.

 

[Staynlean 10+ year member]

It never hurts the amplifier to present it with more impedance than it's rated for, only when we present the amplifier with less impedance than it's rated for do we run the risk of damaging the amplifier. I will attempt to explain why: We know that voltage and current are inversely proportional IF the resistance is constant, we also know that current and resistance are inversely proportional IF the voltage is constant so if the voltage is remaining the same but the resistance in the speaker circuit aka (load impedance) is dropping then the current must be rising, with increased current comes increased heat and the amplifier will only get so hot before it goes into thermal overload and shuts down.

That's why some amplifiers are only rated "stable" to 2 ohms while others are rated stable to 1 ohm, excessive current aka heat is what causes the instability.

Very thankful for your knowledge, awesome stuff thanks man.