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can a car amplifier really use 90a? 

 

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 Post subject: can a car amplifier really use 90a?
Posted: Sun Dec 15, 2013 9:51 pm 
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Hey all, sorry for the lack of posts lately.... I know you all have been so upset without me.
Anyway, ef is sadly gone and I have a 93 gq now, tb42. I seen an amp on ebay the other day ex display for $29 so I grabbed it. Its a 2ch Bezerk amp I plan on using as a mono ( bridged of course i mean )for a 10" pioneer sub (200w rms). Now, this amps a monster and weighs as much as an xr6, but looking at the fuses it supposedly would take 90a maxed ( 3x30a fuses). Surely it would not take 90a right? I'm working out wire and id need 2awg just to run this amp and maybe an additional alternator lol. Please can somene shed some light, 40a I'm thinking but 90 seems overkill
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 Post subject: Re: can a car amplifier really use 90a?
Posted: Sun Dec 15, 2013 9:57 pm 
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How many watts does the amp put out at max?
Take the wattage and divide it by 12. That's how many amps it will take at full load.
From memory multiply PMPO by .707 to get RMS?

 

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 Post subject: Re: can a car amplifier really use 90a?
Posted: Sun Dec 15, 2013 10:06 pm 
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I like Matt's thinking... Power is like everything... It can't be destroyed... Only converted... You want RMS watts too as PMPO watts are s**t...

I low quality amp will however produce a lot more heat than a good quality amp and this heat is also power so whatever Matt is saying plus throw in a few more just to allow for what is lost in the conversion processes...

Some people(and companies) get way too excited with their fuse sizes... Ford for example with their 30A circuit breaker on the power window wiring... If you run 30amp continuous through that wire there isn't a hope in hell it'd handle it without damage... I have no idea what they were thinking when it came to most fuse sizes vs wire sizes actually...

Sure it came with some form of specifications but detailing input power?

My Rotel home theatre amp takes 800W input power to deliver 500W output power as a guide... And that's a good quality amp...

Cheers,
Tim

 

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 Post subject: Re: can a car amplifier really use 90a?
Posted: Sun Dec 15, 2013 10:25 pm 
Getting Side Ways
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cheers for that. Yeah, I normally stay away from cheap amps but for $29 I thought may aswell as its only going in the troll. I was looking at the jaycar 12v fans and might stick one in where I plan ti mount the and run the fan off the trigger. I'll double check but its supposedly 150rms @ 4ohm per channel. I'll only be after 200 rms bridged for the sub. Ill use the formula provided and then run a higher wire to compensate heat and travel from battery. Just thought, f**k man you can get 90a alternators and if this pig want that I'll use it as a door stop.
Cheers lads
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 Post subject: Re: can a car amplifier really use 90a?
Posted: Mon Dec 16, 2013 9:43 am 
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Put a 1 farad smoothing cap inline on the power feed to prevent those huge power sags on big bass notes with the volume cranked .
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 Post subject: Re: can a car amplifier really use 90a?
Posted: Mon Dec 16, 2013 10:43 am 
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If the amp is 1ohm stable, you could easily end up with something like 1x900w with a 2ohm woofer connected.
It might have an input of 13.7v@90a = ~1200 Watts, but with efficiency accounted for at say 75%, you get 900 Watts output.
So it IS possible, but unlikely.


You would be lucky to get it to use that much power. If your power supply is not up to it, the amp output will reduce. Those figures are based on precise lab conditions, and particular tones going through the amp. (or just a random number made up of a series of balls pulled from a bingo barrel)

It is only a maximum rating. The woofer you use will determine the max power draw.



But then being a cheap amp, the fuses are probably wired in series to make it look powerful.. haha
You just never know with marketing departments these days.

 

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