Current draw @ 4ohms vs 1ohm?

[NJack2AF 10+ year member]

Hey I'm obviously no car audio or electronics genius, but I have been doing some reading... Help me out here and tell me if I'm correct.

If an amp is putting out the same wattage at 1 ohm and 4 ohms it is going to pull a lot less current at 4 ohms right?

So if I were to switch from my PA3000DB 2000w ish @1ohm to say a PG Tantrum 1200.1 1200w ish @4 ohms, it will draw far less current right? (obviously because it is lower wattage but say the wattage were the same with the PA were wired to 1 ohm, so say I had the gains down to put out approx the 1200 the PG puts out)

I'm trying to prolong the life of my alt/batt and plan to add comps soon which=another amp. Help me out, "constructive" criticism would be nice if I'm way off. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Thanks

Edit: After reading another post I believe I am indeed way off... still come tell my why and such you car audio geniuses //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Click to read more...

 

[squeak9798 5,000+ posts]

So if I were to switch from my PA3000DB 2000w ish @1ohm to say a PG Tantrum 1200.1 1200w ish @4 ohms, it will draw far less current right?

No.

Edit: After reading another post I believe I am indeed way off...

You are //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif But it's okay...it's a common question/misconception.

In this situation, the impedance that the amplifier is driving is of absolutely zero significance. All that is important to the current draw is the amplifiers efficiency, the amplifiers output power (completely regardless of what impedance it is delivering that power into), and the voltage of the electrical system.

Those are plain and simply the only factors. 1kw is 1kw. And at XX% efficiency on XX.X voltage electrical system, it is going to require XXX amount of current draw to support that amount of power output, completely regardless of the load the amplifier is powering.