Originally posted by jmax
But why bother with a load that voids the warranty when it puts out the same power into 4 ohms? 4 + 4 = 8 / 2 = 4.

Originally posted by TL@altimas.net
exactly.

Originally posted by jmax
But, I think the power output actually drops a little below 1.5 ohms. I could be wrong, but if it is more power at 1 ohm it definitely won't be enough more to hear. The way those amps are designed is to put out almost the same power with everything in the 1.5 - 4.0 ohm range.

Originally posted by phenryiv1




Most amps (good ones, at least) are designed to double output, or get close to it, as impedence drops. Maybe the JL amps are different, but that is how things have been for the last few years. When I was first installing in the early/mid 90's, you multiplied the 4 ohm output by about 1.5 to get the 2 ohm output, but these daus you can estimate 1.75-2 times the power @ 1/2 the impedence. Therefore, 1 ohm power coud be as much as 3-4 times the 4 ohm rated power (under optimum conditions, and with a good amp such as this one...).

on 7/26/02 12:52 AM, Jordan Runsvold at TL@altimas.net wrote:

Hi,
I was wondering a few things about the R.I.P.S. system and how it measures impedance. Does the amp react to impedance changes in real-time, or does it take an impedance reading at turn-on and use that setting until power-down? If it reacts in real-time, how can it produce a flat output with the impedance variances that occur in every driver related to the drivers Fs and other factors?

Playing a sweep through a normal amp would yield a power dip opposite the impedance spike, resulting in a flat response curve. If the JL is adjusting to get full power as impedance rises, there will be an increase in output around the drivers Fs, producing a peak or plateau around that frequency.

Thanks,
-Jordan <((( TL@altimas.net )))>

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Jordan, these are excellent questions. Here we go. The amplifier does not analyze impedance in real time. It does analyze the current on the output rails. The R.I.P.S. system always begins as if it is powering a 4‡ load. If the speaker configuration is such that the amplifier produces an amount of current higher than that which can travel "unclipped" over the output rail, the amplifier can utilize a different output rail with a higher current capability. To make the same amount of power into a lower impedance, an amplifier will need to produce more current and less voltage. If the current reaches a certain level, the amplifier changes the output rail it is using, thus maintaining its ability to generate its rated output cleanly (unclipped). This "shifting of gears" can happen two times (there
are a total of three "gears" or rails in the output section).

The goal is to deliver rated power into a regardless of impedance (from 1.5‡ to 4‡) with out sacrificing sound quality or reliability.

If you have any further questions, please feel free to ask.

--
Tony Ostrom
Zone 3 Area Technical Director
JL Audio Inc.
www.jlaudio.com