Here are the specs on a Jl A1400 amp

A1400
Rated Power 12.5 V: 240 W RMS x 1 @ 4 ohm
400 W RMS x 1 @ 2 ohm
Rated Power 14.5 V: 320 W RMS x 1 @ 4 ohm
500 W RMS x 1 @ 2 ohm

anyone know the difference of rated 12.5 and rated 14.5 volts?

 

12.5 is car not running, just on acc where 14.5 is typically the voltage u get when the enginge is running

 

When I first looked at those specs, they didn't make sense to me:
power should increase AT MOST proportionally to the increase in
voltage, and here voltage is increasing by 16%, but power is
increasing by 33% at 4ohms, and 25% at 2 ohms. I went to the
JL website, and the higher voltage rating is also with 12x the
distortion:
12.5v @ < .08% THD
14.4v @ < 1% THD
I believe the 14.5v rating corresponds to the CES standard,
while the 12.5v rating is JL's more conservative one.
Running at a higher voltage than 12.5, but with a similar low
distortion level should give you a power level somewhere
between the two measures.

 

thanks a lot. Clears everything up.

 

JL dumbs down the power at 14.5, so its closer to the 12.2 voltage, and market it as a "regulated power supply." This is why you arent seeing the numbers you are expecting.

 

actually, this particular amp doesn't appear to have a regulated
power supply, and in fact the confusion was that they were quoting
more power at 14.5v than made sense if the 12.5v rating was
accurate.

 

so...now im confused again. Will this amp do 500x1 at 2 ohms, or will it be closer to 400?

 

this amp will do 500x1 @ 2ohms w/ 1% THD if it's truly getting 14.5v.
if you want the 0.08% THD that it specs at at 12.5v, you'd probably
get 450 watts at 14.5v. Realistically, you probably wouldn't hear
the difference between .08% and 1% THD, especially in a noisy S2000.

 

sorry...what is THD?

 

THD = total harmonic distortion (lower is better)