Current draw question

[Third Eye Vision 0]

I'm wondering why when I changed from 300w @ 4 ohms on my amp, to 600w @ 2 ohms I havn't noticed an increase in current draw. I just picked up a couple Z15s off a seller on here that listed them as DVC4 ohm, and I'm only running one of them due to lack of power/trunk space. I have it wired up to my sae1000d in parallel to get a 2 ohm load. I just pulled a 2 12s out that were wired @ a 4 ohm load on the amp, so I'm going from the 300w @ 4ohm to 600w @ 2ohm. I didn't adjust the gain because the voltage is the same at about 35 volts. But since I'm doubling the amount of wattage being used, shouldnt it be pulling 2 times as much current? The output is about the same as the 2 12's, since the sub isn't broken in yet, and I'm going from 24" of cone area to 15". But I definitely expected to see my headlights start to dim since I'm on stock electrical with only a cap added to the circuit. Is it just because 35 volts is 35 volts regardless of the ohm load, or am I missing something?

[Third Eye Vision 0]

i posted this in the wrong section, can you guys move it to amplifer/electrical for me?

[Kanaworm$ 292]

I'm wondering why when I changed from 300w @ 4 ohms on my amp, to 600w @ 2 ohms I havn't noticed an increase in current draw. I just picked up a couple Z15s off a seller on here that listed them as DVC4 ohm, and I'm only running one of them due to lack of power/trunk space. I have it wired up to my sae1000d in parallel to get a 2 ohm load. I just pulled a 2 12s out that were wired @ a 4 ohm load on the amp, so I'm going from the 300w @ 4ohm to 600w @ 2ohm. I didn't adjust the gain because the voltage is the same at about 35 volts. But since I'm doubling the amount of wattage being used, shouldnt it be pulling 2 times as much current? The output is about the same as the 2 12's, since the sub isn't broken in yet, and I'm going from 24" of cone area to 15". But I definitely expected to see my headlights start to dim since I'm on stock electrical with only a cap added to the circuit. Is it just because 35 volts is 35 volts regardless of the ohm load, or am I missing something?

Depending on the amplifier manufacturer the amp could be a regulated power supply design. Between 4-2-1 ohm the power stays the same.

Unregulated designs draw more current as the impedance drops therefore drawing more current and increasing output.

[Impious 1,476]

Depending on the amplifier manufacturer the amp could be a regulated power supply design. Between 4-2-1 ohm the power stays the same.

Unregulated designs draw more current as the impedance drops therefore drawing more current and increasing output.

That's not a regulated power supply, that would be regulated outputs.

A regulated power supply maintains relatively steady power output with different power input voltages.

But he already stated he has an SAE 1000D, so neither of those scenarios are applicable anyways.

As to the original question......it's hard to say why you aren't experiencing dimming headlights. There are several different factors that could be at play. It may be the musical content you are listening to isn't very demanding. It could be that your various system settings are conservative. It could be that your stock electrical system is strong enough to handle the load. I'm running atleast 600w worth of comparatively inefficient class A/B amplifiers and I have barely noticeable dimming with headlights on and AC running.....my only electrical "upgrade" is the Kinetik HC1800 under my hood. Stupid question, but you have the coils wired in parallel and not series, correct?

Even though the output voltage is the same at 35V, the lower impedance requires the amplifier output more current. The combination of voltage and current is what determines power output. So the amplifier will be outputting more power at 2ohm which requires higher power draw from the electrical system.

Also, you didn't go from 24" of cone to 15" of cone. That's not how cone area is determined. Cone area is listed in the T/S parameters as Sd and is typically stated in cm^2. A typical 12" will have ~480cm^2 of Sd and a 15" ~810cm^2. So a pair of 12's only has about 15% more cone area than a single 15" driver.

[Third Eye Vision 0]

yeah i double checked on 12 volt b4 i hooked them up and i did pos to pos, neg to neg. i have an 80 amp alternator with a autozone duralast gold battery, nothin audio specific, and a 2 farad cap. when i did the 80 x 14.4 and got 1152w, i divided that in half to account for a/c and all that jazz and figured id have roughly 570w reserve for my audio stuff. in the morning ill pull the sub back out and double check the wiring and run my dmm on the amp again. last time i did it, it was at night so i had my buddy watch the dmm in the backseat while i adjusted the gain knob, maybe he read 25 instead 35. thanks for the advice impious

[Duran 387]

A cap huh...

[Third Eye Vision 0]

A cap huh...

yeah no need to talk shit or anything, i got it as a gift and im sure im not worse off by running it. im aware it isnt a magical accessory that gives me the power of a spare battery, but from what i understand it stores a small charge that helps during demanding notes. and since my car puts out around 600 watts and my amp uses 600 watts, im guessing its doing what its designed to do.

[BKOLFO4 29]

I had a 3 Farad cap in my suburban.

18,000 watts, 9 D31T batts, 260 amp alt, (2) runs of 1/0, (1) run of 4/0.

My MIDRANGE amps (old MTX) would dim my headlights without the cap installed.

Caps can have uses, but they are not a substitute for having the proper electrical system. . .

[Duran 387]

I had a 3 Farad cap in my suburban.

18,000 watts, 9 D31T batts, 260 amp alt, (2) runs of 1/0, (1) run of 4/0.

My MIDRANGE amps (old MTX) would dim my headlights without the cap installed.

Caps can have uses, but they are not a substitute for having the proper electrical system. . .

That's the kicker

[lithium 358]

blasphemy!

[Third Eye Vision 0]

Caps can have uses, but they are not a substitute for having the proper electrical system. . .

That's the kicker

i know you didnt have a chance to see taht im only running a 600w amp and that my stock electrical should be able to handle that, but your post with the rolling eyes made it seem like you didnt think a cap was worth anything and that they dont do what they are made to do. i know some people think that they can throw a 2000w amp in their trunk as long as they got a cap and i agree that that isnt waht they are designed to do.