Same RMS at different ohms...

[Mugen 10+ year member]

Why do some amps do this (I've noticed it mainly among JL/Alpine)? If the thing can push 1000w @ 4ohms, why do they limit it to 1000w @ 1ohm? Shouldn't be able to easily push more than that? Is it considered a "feature"? Honestly, if I was spending $800 on a 1000/1, I'd expect more than 1000w //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif

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[squeak9798 5,000+ posts]

Why do some amps do this (I've noticed it mainly among JL/Alpine)? If the thing can push 1000w @ 4ohms, why do they limit it to 1000w @ 1ohm? Shouldn't be able to easily push more than that? Is it considered a "feature"? Honestly, if I was spending $800 on a 1000/1, I'd expect more than 1000w //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif

Yes, the company considers it a feature/benefit.

Their mentality is that it is a benefit to the consumer because it allows them to choose virtually any subwoofer(s) without having to worry so much about "matching" it to the amplifier or receiving a decreased level of power output from the amplifier at a given impedance. You can have a final impedance of anywhere between 1ohm (1.5ohm on the JL) and 4ohm and still receive approximately 1kw of output, instead of only having 250w @ 4ohm, 500w @ 2ohm and 1kw only at 1ohm.

Many like this feature....others don't.....it's all personal opinion.

 

[MassOccur 10+ year member]

JBL Crown amps put out NEARLY the same wattage @ the same ohm loads. Awesome amps.

 

[Flipx99 5,000+ posts]

I am curious how fast this "feature" reacts. Since impedance changes with frequency it looks as thought this would be a benefit as it would maintain a consistant RMS over a longer durartion (in say a sweep)

 

[thylantyr 10+ year member]

If the thing can push 1000w @ 4ohms, why do they limit it to 1000w @ 1ohm?

There are pros/cons to 'power regulating' amplifiers vs. regular amp.

Regular amp

Lets say you bought a 1000w @ 1 ohm amplifier and used your favorite 1 ohm

woofer. All is good, the woofer gets 1000w.

Later you added another 1 ohm woofer and the only wiring option is 2 ohms.

The amp will output 500w @ 2 ohms and each of your woofers gets 250w.

Power regulating amp

You have 1000w @ 1 ohm, you add another 1 ohm woofer in series for 2 ohms

and you get 500w per woofer.

On the other hand, you have a 1000w @ 4 ohm woofer. You upgrade

and add another 4 ohm woofer in parallel. The regular amp has potential

to output 2000w @ 2 ohms, 1000w per woofer, whereas the power regulating

amp only outputs 1000w, 500w per woofer.

 

[thylantyr 10+ year member]

I am curious how fast this "feature" reacts. Since impedance changes with frequency it looks as thought this would be a benefit as it would maintain a consistant RMS over a longer durartion (in say a sweep)

This JL design has multiple voltage rails.

http://www.carsound.com/review_archive/amps/jl_3004.html

The 300/4 has three voltage rails. The claim is that current sensing causes

rail switching. This type of design won't be exact.

Another design may detect the impedance at power up and then just rail

switch one time.

 

[slikrider20 10+ year member]

Yes, the company considers it a feature/benefit.
Their mentality is that it is a benefit to the consumer because it allows them to choose virtually any subwoofer(s) without having to worry so much about "matching" it to the amplifier or receiving a decreased level of power output from the amplifier at a given impedance. You can have a final impedance of anywhere between 1ohm (1.5ohm on the JL) and 4ohm and still receive approximately 1kw of output, instead of only having 250w @ 4ohm, 500w @ 2ohm and 1kw only at 1ohm.

Many like this feature....others don't.....it's all personal opinion.

I think it's a pretty cool feature. I think the PG Xenon amps are that way too.

 

[Mugen 10+ year member]

The only reason I think it's dumb is because it's limiting potential power the amp could put out. I guess if you need an amp to push 4ohms, it's good. But if you have a 1ohm load, I wouldn't touch those "restricted" amps, seems like a waste of cash.

 

[Flipx99 5,000+ posts]

Why is it bad? It is not limiting but more accomodating

 

[SPL140.2 5,000+ posts]

x2 you may have a 1ohm sub but after box rise you may only be gettin the 2ohm rating on the amp I think its a great feature just wish they could put that on Big amps //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[JoshHd6 10+ year member]

x2 you may have a 1ohm sub but after box rise you may only be gettin the 2ohm rating on the amp I think its a great feature just wish they could put that on Big amps //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

x2........im bored get on aim..lol....//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[mike dressure 10+ year member]

i love that feature. especially at 12.5 volt's

 

[squeak9798 5,000+ posts]

The only reason I think it's dumb is because it's limiting potential power the amp could put out. I guess if you need an amp to push 4ohms, it's good. But if you have a 1ohm load, I wouldn't touch those "restricted" amps, seems like a waste of cash.

I'm not following your logic?

If you need 1kw @ 1ohm, what's wrong with an amp that does 1kw @ 1ohm and 1kw at higher impedances aswell?

If you needed substantially more than 1kw @ 1ohm...then you wouldn't be looking at this amp in the first place so it's a moot point.

 

[azbass 5,000+ posts]

its not limiting anything //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[JimJ 5,000+ posts]

Honestly, if I was spending $800 on a 1000/1, I'd expect more than 1000w

The value of dollars per watt is entirely relative //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Genesis and Brax continue to sell amps...

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif