Tested voltage drop with most accessories off last night. At idle the car rests at 13.9x, With a variety of music and an Iasca test disc, at the loudest volume i can play the factory stereo at while still sounding decent, the lowest i got it to drop was 12.69, it was mostly between 12.7xx and 12.9 on HARD hits. Electrical system is stock, battery, alt, etc, all stock, no cap/ 2nd battery, extra 0wag ground under hood to battery, extra 4awg ground running to rear of the car where it joins the 1/0 that goes into my amp. Amp is an MTX 81000d running @ 2ohms, Rated 1krms @ 12.5 volts, most people get between 12xx and 14xx on their birth sheets at that voltage. I was just surprised that for no real electrical upgrades it wasn't really fluctuating more than 1 volt. Any thoughts?

This is the only other thing, i tapped into my factory preout from the headunit before it reached the factory amp. This is supposedly a low level signal, but i used a line out converter on it. I'm thinking that perhaps it is giving off a pretty weak signal to the amp. haven't had the chance to test it though.

Edited October 2, 200816 yr by manbeer

I think you're safe with that. As long as you don't dip below 12 volts you're good. I think I read that 11v can damage an amp? Someone verify that though.

Just out of curiosity what is the max volume you use on your head unit...i.e. 25/50

I think you're safe with that. As long as you don't dip below 12 volts you're good. I think I read that 11v can damage an amp? Someone verify that though.

Just out of curiosity what is the max volume you use on your head unit...i.e. 25/50

Unless a song is unusually quiet or loud, on 90% of music i do 23-24 out of 32. To be honest, i am really surprised that i'm not getting a much worse drop cause when i was reading about this amp everyone was talking about how much of a current hog it was, and it calls for 150 amp fuse, which makes me think that i am not pushing it to full potential

i just tested the voltage from the rca's leading from the LOC with a couple sine wave sweeps and output level maxed and got a max reading of .297 volts. So i guess having my gain on the amp just about all the way up is just about right.

Not dropping below 12.6 is pretty good imo.

are you metering up front or at the amp.

are you metering up front or at the amp.

up front, at the battery

What size is your alternator? That's the real question that should be asked. If it's 300 amps, then no I wouldn't expect a drop at all. If it's 60 amps, then yeah that's weird at idle.

What size is your alternator? That's the real question that should be asked. If it's 300 amps, then no I wouldn't expect a drop at all. If it's 60 amps, then yeah that's weird at idle.

I believe they are 110 amps

meter in the rear... as your voltage will be lower from the run alone

meter in the rear... as your voltage will be lower from the run alone

ahhh i always metered drop for the car and not for the amp

i hear ya... but to see actual voltage as the amp sees it you dont think you would get a better idea metering from the rear?

Too low of a voltage causing damage will depend on the power supply. Unregulated will make more power as voltage increases to a point, where as regulated with stay steady with a +/- shift in voltage. There is no general rule of thumb here as every amp and every power supply will differ.

So i just retested it, same track, same settings, this time i remembered to urn off heated seat, and no interior lights as it was light out.

Resting Voltage

14.04 under hood

14.03 @ amplifier

Lowest drop was 12.9x under hood

12.59 @ amplifier

amp is getting a pretty solid connection from what i can tell. this makes me feel a little more confident about running @ 1ohm with a second battery and better cable (currently using raptor 1/0 which seems like 2 gauge, gonna switch to Kolussus 1/0, which i hear is actually 2/0?)