Jbl 1200.1

[97ranga]

I just recieved the amp I bought (JBL 1200.1) and I must say I am impressed. It is a great amp, pounds the hell out of my Audiobahn 12". The only problem is that I need to get a bigger alternator or a cap or something (and I dont want to spend anymore money on my system :mad: ) Oh well, for as long as my battery stays up I'll be pimpin

[PigglyRoot]

cool, how much did you pay for it?

[Tempe]

yeah, how much?

ditch the cap idea. stash that $ in your piggybank and save for an alternator upgrade. if your amp isn't getting enough power from your alternator, adding an additional load to your electrical system will not help. caps do not produce power--alternators do.

tempe

[PigglyRoot]

i agree with tempe, for what a cap costs, you could save a little more and have a better performing alternator instead of trying to milk this one for what its worth.

[Locke]

Originally posted by Tempe
yeah, how much?

ditch the cap idea. stash that $ in your piggybank and save for an alternator upgrade. if your amp isn't getting enough power from your alternator, adding an additional load to your electrical system will not help. caps do not produce power--alternators do.

tempe

Actually, on a DC system, a cap technically isn't a load, its an open circuit. But he's still right. Get a better alternator or you'll end up replacing it anyway. With an amp that's pulling 100A, you might even need both.

[97ranga]

I paid 280.00 for it off of ebay, brand new... I love it. Oh and I did ditch the Cap idea, I'm going to save up and get a 170 amp alternator... the should do me fit

[Tempe]

Originally posted by Locke


Actually, on a DC system, a cap technically isn't a load, its an open circuit. But he's still right. Get a better alternator or you'll end up replacing it anyway. With an amp that's pulling 100A, you might even need both.

courtesy of a generous soul, i was able to have someone put my thoughts into MUCH better words....

"No, you (Tempe) got it. Once the cap is discharged, it has to draw current from somewhere to recharge. An open circuit would make the cap a fuse, and what good would that do you for 100 bux? (almost as much good as a regular cap will for DBDrag ) ANYTHING you add inline with the alternator is seen as a load, even a battery. once the battery expends its power, it doesnt just sit there till the alternator isnt doing anything to get recharged... anything that has a lower voltage level than the alternators potential tries to draw current from the alternator... untill the point where the alternators voltage drops below that point as well. Anything with a DC input will add to that total till you get your max current draw in your system.

"You (Tempe) had the right idea with the alternator. The only way you are going to get more current without taxing the alternator to death is to go to an isolated 12 volt or 16 volt system that is not part of the loop with the rest of the car. you would have to use a diffrent source to charge it such as a battery charger. If you were to hang a gob of batteries off of the current alternator, you would in effect just be adding one more thing the alternator has to charge. Thats one of the reasons when you walk around a large comp (such as USACi finals) you see people quabbling over places to plug in thier chargers. Not only can you NOT run your vehicle in the building (i.e. charge it with the alt.) but most systems would strangle an alt. anyway.

"Heres another way to think of it. you know how amplifiers are only stable into a certain ohm load? Thats because at a certain level, the amplifiers components basically see a dead short across the terminals if you drop too low. It was once said in a magazine article that "most high current amplifiers today can practically arc weld" ... and that is not that far off from what a .5 ohm stable amp is doing. Well... as you add loads to any electrical device (unless it is heavily regulated) it wants to output more and more power... and eventually you will reach the limit of what your components can withstand and you blow something up (or melt something). this is no diffrent for a car alternator.

"The battery acts as a safety net for the alternator. like I said before, the alternator will only try and charge something so long as the items voltage level is below that of what the alternator is. So youre out playing your system really loud. Your alternator supplies voltage and current untill your system starts drawing enough that your alternators voltage drops. Once the alternators voltage is equal to that of the battery, then the battery steps in and starts supplying current. At this point your alternator isnt doing much of anything other than constantly outputting power. However, once you start to deplete the batterys reserve of current, its voltage starts to drop again, and the alternator sees this and tries once again to charge the battery as well. The voltage levels leapfrog over one another till one of the items reaches the point of no return.

"if you want to see a good visual representation of this, hook up an analog voltmeter (the one with the needle) to your battery posts. When the car is running, youll see something around 13.8 14.8 volts. Now play your system... start off mild and watch the voltage level. After a bit, go nuts... the voltage will drop quickly till it gets to the 12 volt level... then the battery steps in and your voltage levels off for a bit... however, when you start draining the battery, youll see the voltage level start to come down again.

"it is better to do this with just bass information. high frequency amps have such a dynamic headroom that it can change its voltage requirements30 to 40,000 times a second. Most batteries are not able to keep up with a change that quickly, so voltage drops for an instant. Its not that its a huge load in this case... its just that it changed voltage levels so quickly as to be able to outrun the batteries ability to keep up. Thats where capacitors and ultra low ESR batteries like SVRs, Optimas, and Battcaps (to name a few) come into play."

Tempe