if an amp is rated 150w @ 4ohms, how do you figure watts at 2ohms.the amp only gives 4ohm rating but has ex jack and states 2ohm min load.thanks
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watts/impedence question
- Thread starter rptrsn2
- Start date
alexclaber
Commercial User
You can't without knowing the technical details of the power amp design. It could be as high as 250W or as low as 100W. Whatever it is it's unlikely to make a substantial dB SPL difference.
Alex
Alex
billfitzmaurice
Commercial User
- Sep 15, 2004
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- Owner, Bill Fitzmaurice Loudspeaker Design
If the amp only gives the 4ohm rating, that means it's not meant to run lower than that. Doing so will damage it. 
If the amp only gives the 4ohm rating, that means it's not meant to run lower than that. Doing so will damage it.
Usually it will tell you what load the amplifier is stable to. In the car audio world its usually ~2x more per drop in ohms. 4 = 125, 2 = 250, 1 = 500 etc..
it only gives 4ohm rating but like i stated earlier it has an ex jack and clearly says "2 OHM MIN LOAD" do you think they would put that if it was not 2 ohm capable?If the amp only gives the 4ohm rating, that means it's not meant to run lower than that. Doing so will damage it.
In the Bass Amp world, it's more like 8 = 200, 4 = 350, 2 = 480. The power supply (120VAC to DC) is not beefy enough to keep up at lower impedances, mostly to save weight.
Car audio doesn't have the power supply problem, since it uses battery voltage directly. It doesn't need a huge, heavy transformer. So, their watts are directly comparable with impedance.
(Car audio is specified in peak watts, not RMS, so their numbers are inflated compared to bass amps.)
