Red-CL

I know that the JL 500/1 has a rms rating of 500 watts but I can't find any info on peak power.

Anyone know what it is or where to find it?

elduderino

The JL "slash" series is a stiffly-regulated amp. I believe that means that it puts out 500W, into 1, 2, or 4 ohms, and from 11 to 16V. That's it.

jpswanberg

i remember reading a magazine test a few years ago where the actual power was closer to 600w, slightly more into 2 ohms than 4 ohms. unfortunately, the difference in volume between 500 and 600 watts when fed into a sub is negligable. you would have to double th power (to 1000 watts) and have a sub that can translate that much power into music,as opposed to heat if you wanted as appreciable increase in volume. jps

elduderino

Remember, that's actual, not peak : )

TommyJ25

Right, thats acutal RMS. Peak watts for an amp is a totally useless number and doesn't mean anything. Cheap brands usually try to advertise their products by naming a high peak power, which is worthless.

elduderino

Well, that's not really true either. There ahve been home and car amp brands that have focused on "dynamic headroom". The idea behind dynamic headroom is taht musical peaks are far less frequent than one would think, and that if an amp can handle momentary peaks with a lot of power, a lower continuous rating is OK - especially because that kind of amp is cheaper to make.

It tends not to apply a whole lot to bass amps, since bass in modern pop music is almost like a test tone in terms of load, but it highlights the diff between loosely regulated amps with headroom and stiffly-regulated amps without it.

Back in the day, car stereo had a big divide, with Phoenix Gold, Rockford, Orion, Alpine, and most others going loos-regulated, and PPI, Hifonics, Zapco, xtant, and others going stiff-regulated and no headroom. (Many of the latter brands have changed hands and manufacturing philosophies and are no longer made that way, at least not all of them).

If you want to read a good article about this (and NAD's designs to take advantage of the cost savings) read this:

http://stereophile.com/asweseeit/489/

jstadt

Hello All,
The JL 500/1 is quite regulated in its power supply. As opposed to a stout linear supply, the power does not double or really go up as the ohm load lowers. This is true of most switching power supplies.
However, it does exceed the specs. If you go to ecoustics. com you can find some professional reviews. I believe that it is approx. 600w. I am cuurently using a 500/1 to drive a JL 12W7 prowedge to good effect with a JL 300/4 driiving Focal polykevlar seperates.
Cheers,
Jstadt

TommyJ25

Yeah, I have a 10W7 Prowedge being pushed by a 500/1. Perfect compliment to this sub. If I were to get my hands on a 12W7 or 13W7 Prowedge, I would do it right by powering it with a 1000/1. You aren't going to hear the full capabilities of that sub unless you give it a 1000 rms, and the 1000/1 is a perfect match.

elduderino

Welcome, good points, just adding a couple of comments.

Per JL Audio when talking to them on the phone a while back, the "slash" series of amps actually reads the DC resistance across the speaker terminals on power up and adjusts the power supply rails in order to provide the rated output power (or a little more) across that DC resistance. That is supposed to be why it gives the same power into various impedances. Note that I am quoting them and not speaking from personal experience.


Again, it sure does - on a continuous basis - not on a peak "dymnic headroom" basis.

This is the diff between the "slash" series and the "e" series.