Will An Amp Run Cooler on 2 vs 4 ohms at the Same Output?

[Stealth1]

The question is in the title. At the exact same output wattage, are there any differences in amp efficiency, heat generation, etc, when running otherwise identical speakers (but 4/2/1 ohm being the variable)?

[diy.phil]

We need a scientific test!

[ckirocz28]

The question is in the title. At the exact same output wattage, are there any differences in amp efficiency, heat generation, etc, when running otherwise identical speakers (but 4/2/1 ohm being the variable)?

There are differences in efficiency at different impedances, watch some of BigDWiz's amp dyno vids. Even power cable size will change efficiency.

[BigAl205]

Class-D will run cooler at lower impedances, where pure class-A could fry an egg at 4ohms.

[Stealth1]

There are differences in efficiency at different impedances, watch some of BigDWiz's amp dyno vids. Even power cable size will change efficiency.

I watched a few of his videos however he was not mentioning efficiency in the ones I saw (I will need to crunch some numbers).

I am thinking about differences in efficiency, heat generation, and other factors that I might not be aware of, for the exact same amp and wattage output, but just with different speaker impedances.

It would also be interesting to know the variation between D Class and AB in these regards if anyone knows.

[JCsAudio]

Apples to apples the same amplifier will run hotter on a 2 ohm load vs a 4 ohm load (speakers) because more amperage flows through the mosfet’s with lower impedance speakers. With increased heat comes reduced efficiency typically.

[ckirocz28]

Class-D will run cooler at lower impedances, where pure class-A could fry an egg at 4ohms.

I've still got one early 90's cheater amp that will fry an arm at 1/2 ohm.

[ckirocz28]

I watched a few of his videos however he was not mentioning efficiency in the ones I saw (I will need to crunch some numbers).

I am thinking about differences in efficiency, heat generation, and other factors that I might not be aware of, for the exact same amp and wattage output, but just with different speaker impedances.

It would also be interesting to know the variation between D Class and AB in these regards if anyone knows.

He usually shows the dyno sheet which will have the efficiency written on it. Pause.

[Stealth1]

He usually shows the dyno sheet which will have the efficiency written on it. Pause.

thanks for the tip! The few videos that I watched actually had that omitted from the sheets that he wrote up. However, this was a good exercise in doing some math.

[ckirocz28]

thanks for the tip! The few videos that I watched actually had that omitted from the sheets that he wrote up. However, this was a good exercise in doing some math.

Well damn, you must have watched the videos I haven't seen.