Just picked up a cheap $20 Alpine MRP-F200 4 channel amp off craigslist. I figured for $20 what the heck it HAS to be better than the crappy amp in the factory radio! (A 10wpch TA8275H chip!) the sticker on the amp claims 75wx4 which i took with a serious grain of salt and i was a bit surprised actually! On the bench it produced 55w from one channel into a 4 ohm load at the onset of visible clipping! It gets to 58-60w at 1% at a guess and that's a heckofalot better then i had expected it to do...BUT that was only ONE channel running and it was drawing 10 amps at 14.4V from the power supply at that level and i see that it only has a 25 amp fuse! LOL! there is no way that power supply will hold up with all four channels doing that! I won't even try it hahahhaa
I see that the more current specs list the amp at 40wpch 20-20K at .08% distortion and....yeah i could see it doing that. maybe with one pair of channels running... I might actually try that on the bench and see how close it will get.
I haven't actually listen to it yet. have heard some not so great reviews of this amp but as i said...for $20 what the heck!
I see that the more current specs list the amp at 40wpch 20-20K at .08% distortion and....yeah i could see it doing that. maybe with one pair of channels running... I might actually try that on the bench and see how close it will get.
I haven't actually listen to it yet. have heard some not so great reviews of this amp but as i said...for $20 what the heck!
With both channels running into a 4 ohm load at 100hz and maintaining 14.4V at the amplifiers power terminals i was able to get 56.25 watts per channel at the onset of visible clipping. again 1% distortion numbers would probably be about 58 watts. current draw at clip was 20 amps. the fuse is rated 25 amps!!
so that's 112.5 watts total. the revised specs claim 40wpch, 160 watts total. can it eek out another 47.5 watts with the remaining 5amps??? I don't think so but close.
Doing the math based on observed numbers. 112.5 output watts divided by 20 amps line current draw = about .178 amps per watt. multiply that by the claimed 160 watts and you get 28.45amps roughly. almost 3.5 amps more than what the fuse is rated for.
With music program content im sure it will hit 40wpch on peaks without much issue. But to get there, you need some good control of power. heavy gauge wire etc. But calling it for what it is. and i would even step it down a bit and say it is a 35wpch amp. I can see why it got such a bad review when people where thinking it was the 75 watts per channel that it claimed!
so that's 112.5 watts total. the revised specs claim 40wpch, 160 watts total. can it eek out another 47.5 watts with the remaining 5amps??? I don't think so but close.
Doing the math based on observed numbers. 112.5 output watts divided by 20 amps line current draw = about .178 amps per watt. multiply that by the claimed 160 watts and you get 28.45amps roughly. almost 3.5 amps more than what the fuse is rated for.
With music program content im sure it will hit 40wpch on peaks without much issue. But to get there, you need some good control of power. heavy gauge wire etc. But calling it for what it is. and i would even step it down a bit and say it is a 35wpch amp. I can see why it got such a bad review when people where thinking it was the 75 watts per channel that it claimed!
For $20.00 it sounds like you did alright to me. Most car amps nowadays rate their amps at 2 0hms not 4 ohms. So maybe that is why they have such inflated ideas of output. Still all in all depending on your needs and tastes, I still think your on top with this deal...Congrats!!
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