rcz22

I can't find any reviews out there on the Alpine MRD - M501 amp. I want to know how reliable it is, at least compared to the JL 500/1 amp, and if its powerful enough to run 2 JL 10W3V2 subs in a sealed box. I ask because its like half the price but rated at basically the same wattage.

Any comments/suggestions are welcome.

Thanks.

elduderino

Both those are reliable units. That's not the diff.

According to this, the Alpine is rated at 275W RMS into 4 ohms at 14.4V. It makes 550W at 2 ohms at 14.4V. The 12V ratings are 225 and 425.

The JL is rated at 500 watts anywhere from 1.5 to 4 ohms, anywhere from 11-14.5V. The first is true because of the smart power supply rails that self-adjust to the speaker load every time the amp is turned on. The second is due to the stiffly-regulated power supply that makes your speakers sound the same even if your voltage dips (no caps needed, and you sound is the same at idle or at high RPMs on your alternator!) These are better ways to build an amp, but they cost more to do...

But if you're seeing the Alpine real cheap, it's probably because it's been discontinued, and is being blown out for the 2005 model.

rcz22

The setup that I was looking at was to run the 2 JL 10's @ 2ohms, since the amp can run 550W @ 2ohms...now I pretty much know NOTHING as far as what this means. I've done a little research, does this mean that the amp is working twice as hard to pump out 550W and therefore will burn out quicker?

elduderino

Not really... what it means is that Ohm's law says that resistance, voltage, and current are all interrlated and you can't change one without changing the others.

There are some who say that running an amp into 2 ohm impedances can screw up the amps damping factor and slew rate - specs that describe how well the amp can control the faster motions of the cone. A point of argument, but worth knowing.

With the Alpine, changing the speaker impedance/resistance changes the load seen by the amp - the power supply voltage internally stays the same, so the amp draws more current to compensate. Runs hotter as a result, and theoretically could shorten the lifespan, since electronics hates heat - but not enough to notice, I suspect.

With the JL Audio, when the speaker impedance changes, the amp "sees" this and changes the power supply voltage to compensate, so the amps stay the same and the heat stays the same.

Same with the input voltage. The Alpine depends on the input voltage to stay high and constant, or its internal power supply voltage will drop as soon as the outside voltage drops. The JL regulates the PS voltage internally, and is not subject to the external variations that the Alpine is as a result (as long as the voltage stays above 11V).

So if you buy a Civic, it's a good car and better than a Cavalier or a Focus... but it's still a Civic.

The Alpine is a Civic, the JL is an Acura.

ou sig

that will be good power for those subs. I have 738 total watts to my 2 subs (at 2 ohms) and they play great