Runnng an amp at half it's rated ohm load

[AMI CUSTOMS]

lower ohm load increases heat in the amp and thats what causes them to fail, heat. my way around it is putting the amps in an amp rack with a couple fans moving air through the rack. keeps them nice and cool. ive ran strapped at .5ohm and each amp at .5ohm with voltage drops just touching 11v. never burnt an amp.

imp rise wont save the amp during music. it may help, but every time the cone is at rest the amp sees nom. load.

Wiring down in ohm load isn't what increases heat, the additional current is what creates that heat from the voltage drop, if you have ZERO drop, you are able to keep the voltage up, then it will NEVER get not at any ohm load!!!!! The drop creates the heat.

Other questions above, IMP RISE is calculated by this

OHMS LAW

You must current clamp one of your speaker wires coming out of the amp, it doesn't matter which one, and read ac current. You must do this at full tilt with a burp of your vehicle peak. So play a track of where your system TL meters the highest!!!! Do the same test with a DMM set to ac voltage and measure the ac voltage coming off the speakers leads, + and - . You can do both of these measurements at the same time if you have a current clamp and DMM and set both to peak hold. Take those two values and divide like so ACvoltage/ACcurrent that number will be your resistance,,,,example

ACVoltage measured 114

ACcurrent measured 81

114/81 = 1.4 ohm

You can also take those numbers and multiple them and get your real amp power at peak!!! 114*81= 9234 Watts

The above example is when I am wired at .5 ohm.

[skittlesRgood]

lower ohm load = more current = more heat.

[AMI CUSTOMS]

lower ohm load = more current = more heat.

You get heat from voltage sag. And not have correct electrical, sure you will get more heat if you try to pull 300 amps thru some 4 gauge cable that is 15 ft long.

[skittlesRgood]

we arnt talking about wire. current runs though the amp. if your theory is correct, I could make a 3000w amp with 5amp mosfets on the power supply. as long as i dont have voltage drop, somehow those wont overheat and burn up?

[AMI CUSTOMS]

You have any idea how many 5 amp mosfets you would need to make 3000w....LOL

Edited November 6, 2010 by AMI CUSTOMS

[00sdime00]

You get heat from voltage sag. And not have correct electrical, sure you will get more heat if you try to pull 300 amps thru some 4 gauge cable that is 15 ft long.

Sure you will get heat from voltage sag. That's basic electronic theory. As the voltage goes down the power supply will try to compensate by drawing more current....up to a point where things start to fail if protection don't kick in. Skittles is also correct. By loading an amp down like that, the current flowing through the output section and power supply will go UP. Ohms law as you stated ealier. If I were to compare readings(directly off of the output FETs and power supply FETs) of any amp with a steady input voltage (Say 14.4V) wired at 1Ω vs .5Ω, I would bet you my paycheck that the amp wired at .5Ω would be hotter. Depending on how well the amp was designed along with how much thermal mass the heatsink has, there may be a slight difference...but there would be a difference.

Nicks bitch about wiring that low has to do with current also.....the current flowing through the coil/coils of the sub.(That and the "junk" Korean amps...lol) Think of it like this....you have 2 amps. Both do 3kw, only one does 3kw with 100vac and 30a at the terminals. The other does 3kw with 50vac and 60a. Which one do you think will toast a coil first? 60a is a lotta current to pull even through an 18ga coil winding.

[AMI CUSTOMS]

Sure you will get heat from voltage sag. That's basic electronic theory. As the voltage goes down the power supply will try to compensate by drawing more current....up to a point where things start to fail if protection don't kick in. Skittles is also correct. By loading an amp down like that, the current flowing through the output section and power supply will go UP. Ohms law as you stated ealier. If I were to compare readings(directly off of the output FETs and power supply FETs) of any amp with a steady input voltage (Say 14.4V) wired at 1Ω vs .5Ω, I would bet you my paycheck that the amp wired at .5Ω would be hotter. Depending on how well the amp was designed along with how much thermal mass the heatsink has, there may be a slight difference...but there would be a difference.

Nicks bitch about wiring that low has to do with current also.....the current flowing through the coil/coils of the sub.(That and the "junk" Korean amps...lol) Think of it like this....you have 2 amps. Both do 3kw, only one does 3kw with 100vac and 30a at the terminals. The other does 3kw with 50vac and 60a. Which one do you think will toast a coil first? 60a is a lotta current to pull even through an 18ga coil winding.

I know exactly what you are saying, my point was that lower voltage with lower ohm load is what creates that heat, not just wiring to lower ohm load. If I wire to .5 ohm and my voltage drop 4 volts vs. no drop, which one would have more heat? Obviously my amp is gonna get hella hotter with the larger voltage drop, NOW was that from wiring it down in ohm load? NO!!! My electrical couldn't handle it, so my voltage sagged and created the heat from the increase in current flow....

I guess maybe I am just looking at this from a input side only and he is stressing output side....LOL

Edited November 6, 2010 by AMI CUSTOMS

[00sdime00]

I know exactly what you are saying, my point was that lower voltage with lower ohm load is what creates that heat, not just wiring to lower ohm load. If I wire to .5 ohm and my voltage drop 4 volts vs. no drop, which one would have more heat? Obviously my amp is gonna get hella hotter with the larger voltage drop, NOW was that from wiring it down in ohm load? NO!!! My electrical couldn't handle it, so my voltage sagged and created the heat from the increase in current flow....

I guess maybe I am just looking at this from a input side only and he is stressing output side....LOL

I can't multiquote right now and it's a pain in the ass to post as it is, but I will quote one of your earlier comments... "Wiring down in ohm load isn't what increases heat, the additional current is what creates that heat from the voltage drop, if you have ZERO drop, you are able to keep the voltage up, then it will NEVER get not at any ohm load!!!!!"

I guess you missed my point that wiring it to a lower Ω load WILL increase the heat produced due to the increased draw from both the output section and power supply. Regardless of if the input voltage is sagging or not. Now I understand that in your case, you had inadequate electrical to support your amp running at .5....I'm on your page, but I don't think you're on mine.

And thats the end of my lesson for this morning. lol

[AMI CUSTOMS]

I can't multiquote right now and it's a pain in the ass to post as it is, but I will quote one of your earlier comments... "Wiring down in ohm load isn't what increases heat, the additional current is what creates that heat from the voltage drop, if you have ZERO drop, you are able to keep the voltage up, then it will NEVER get not at any ohm load!!!!!"

I guess you missed my point that wiring it to a lower Ω load WILL increase the heat produced due to the increased draw from both the output section and power supply. Regardless of if the input voltage is sagging or not. Now I understand that in your case, you had inadequate electrical to support your amp running at .5....I'm on your page, but I don't think you're on mine.

And thats the end of my lesson for this morning. lol

I got it, I was with ya when you first said it, since you increased current demand on the output side the heat would result.

[skittlesRgood]

You have any idea how many 5 amp mosfets you would need to make 3000w....LOL

*face palm* you really aren't getting this...