Amp power ratings HELP PLEASE

[dlittlelion]

Im presently in the market for an amp to power my Pioneer TS-W2000SPL DUAL 2 OHM

Im seeing on the market amps rated from as low as 1000W to as high as 5000w with the same amperage fuses 2x35Amp

Im seeing amps by the same manufacturer but different series rated at the same wattage but different fuse ratings and in some cases half the price.

Tell me people what to look for? how to select the correct amp for my application? how to know if the stated output ratings are correct?

Thanks much

[nervewrecker]

Usual rough estimate is

"fuse rating x 10"

for power output.

Can be more, can be less for some amps.

[triston]

Thought was to multiply fuse by car voltage.

[nervewrecker]

Thought was to multiply fuse by car voltage.

Correct, but then you have to factor in efficiency. Cant be sure about it for all amps.

Class d maybe 80% or more, class ab all kinda 50% and up.

Few people have perfect voltage of 14.4 - 14.6 running with a hot alternator. Its more like 13.6 - 13.9 depending on the system load.

So unless you have the efficiency factor and a calculator on standby a 13.6 x fuse rating x efficiency and can factor in impedance rise due to the many factors 10 x fuse rating is a reasonable estimate.

Amp with 40A fuse usually does approx 300 to 500 watts typically, amp with 50A fuse usually does 400 to 600 watts so the "fuse rating x 10" calculation is a reasonable estimate, no?

[triston]

Cool. Well they say u learn something new each day. Not much in music scene.

[- Rovin's car audio -]

in addition to what nerve said : like always u get what u pay for

some of d cheaper amp brands even though they may do rated & have same fuse rating sound kinda "hollow" so say if u buy a cheap amp for $1200 it may not sound as nice as 1 for 2-3 times d price with same power rating ...

[nervewrecker]

Been there done that.
Amp lacked on the low and high end. Lack of midbass and high crisp notes. Made me feel like I running low quality mp3.
Was a mainstream big name brand too eh.

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[brandonology1]

I always wanted some clarification on this inno... good info... correct me if I rong, but I read somewhere that the operating temp of the amp also affects the efficiency??

[nervewrecker]

That I'm not sure about.
I know current has a heating effect. When voltage drops the amp will increase the current draw to make power. Volts x amps = watts.
More current = more heat.

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[dlittlelion]

so if my sub is rated at 750watts rms what should i look for in an amp?

[SR]

1000rms at 12.5 volts should be fine

[nervewrecker]

Most amps dont publish putput at 12 this rounds so say 1.5kw to 1.8kw at 14.4v is safe provided you have a decent charging system. This way you have some headroom on the sub so you don't have to stress the amp to power it up nicely.

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[- Rovin's car audio -]

my personal recommendation 25-50% more than rated

i have done 2-3 times rated without problems but wont recommend it unless u really know what ur doing ...

[Sully]

Why keep speculating? There are several persons on the forum that have meters that can measure the output of an amplifier. Just take it to one of them, and get it tested. There's usually a nominal fee, but at the end of the day you get measured results, which are difficult to argue with.

[3stagevtec]

my personal recommendation 25-50% more than rated

i have done 2-3 times rated without problems but wont recommend it unless u really know what ur doing ...

DBX recommends using an amplifier 1.5 times the speaker rating.. I generally use 1.5 - 2 times on all my equipment.