current draw

[jellyfish420 10+ year member]

i checked my voltage today and @ battery it was 14.4 idle. when i cranked the system up the lowest it dropped was 14.1. the question is...if my voltage doesn't drop is there still a possibility that the current is dropping down to far. i installed a new(bigger) amp the other day, and it just doesn't seem to be hitting as hard. could it be drawing too much current and is there any way of checking current? also i measured the rca voltage, and it was only .1V could this be another reason that my amp doesn't seem to put out what it should. would going to a H/U with say 4V preouts be any louder? one more question, does anyone know the formula to take the output volts from the amp and figure out the watts?

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[supa_c 5,000+ posts]

http://www.the12volt.com/ohm/ohmslaw.asp

 

[RattlinStratus 10+ year member]

i checked my voltage today and @ battery it was 14.4 idle. when i cranked the system up the lowest it dropped was 14.1. the question is...if my voltage doesn't drop is there still a possibility that the current is dropping down to far. i installed a new(bigger) amp the other day, and it just doesn't seem to be hitting as hard. could it be drawing too much current and is there any way of checking current? also i measured the rca voltage, and it was only .1V could this be another reason that my amp doesn't seem to put out what it should. would going to a H/U with say 4V preouts be any louder? one more question, does anyone know the formula to take the output volts from the amp and figure out the watts?

The 4volts would not make a difference in being louder or not, but it may sound better. I doubt that little drop would make a difference. I had a 2 volt drop when my stereo is cranked and it slammed. Honestly I would get a capacitor. SInce your voltage drop is minimal and your amp lacks power so it seems, the cap would store up "extra" energy and shoot it to your amp when big bass notes hit. I know people will say not to get a cap, but I know my caps saved my stereo from killing itself, and if you use them right they are great.

 

[johnecon2001 5,000+ posts]

The 4volts would not make a difference in being louder or not, but it may sound better. I doubt that little drop would make a difference. I had a 2 volt drop when my stereo is cranked and it slammed. Honestly I would get a capacitor. SInce your voltage drop is minimal and your amp lacks power so it seems, the cap would store up "extra" energy and shoot it to your amp when big bass notes hit. I know people will say not to get a cap, but I know my caps saved my stereo from killing itself, and if you use them right they are great.

Thats a bad idea. Ask any one here who knows what they're doing, knows that caps are a horrible idea. He's only getting a .3 voltage drop.. thats hardly anything. I would recommend, If you havn't done it already, the big 3. Or if you have already done it, increase the guage of wire that you used to help "lube" up the elctricity movement, so to speak. If you don't want to do that, go for a new battery, with more CCA's and a better AH capacity.

You know how caps are man, they cause more harm than anything else.

 

[req 5,000+ posts]

i would imagine that a .1v preout may be the cause, most are like 1.7v dude. thats really REALLY bad. with such a low input voltage, theres really nothing to amp, and then -> no sound.

might wanna look at that before you look at your wiring.

 

[jellyfish420 10+ year member]

Thats a bad idea. Ask any one here who knows what they're doing, knows that caps are a horrible idea. He's only getting a .3 voltage drop.. thats hardly anything. I would recommend, If you havn't done it already, the big 3. Or if you have already done it, increase the guage of wire that you used to help "lube" up the elctricity movement, so to speak. If you don't want to do that, go for a new battery, with more CCA's and a better AH capacity.
You know how caps are man, they cause more harm than anything else.

ya i know better than caps!!

 

[sumone 10+ year member]

(E^2) / R = P

voltage squared divided by resistance(nominal impedance in this case) equals power in watts.

what were you playing (music or sine waves) and what volume was your HU at when you measured the voltage off the RCAs? @ 25/33 on mine (1.8V preamps), I get around .4 volts playing a 0dBFS 1khz sine wave. My amp probably never sees 1Volt from the HU. HUs don't put out the max voltage under normal conditions. they always have headroom for their bass & treble boosts and stuff. that's why if you turn up the HU ALL the way up, keep dsps & eqs off, and measure voltage, you still won't see the max voltage (and if analyzing with a scope, you'd most-likely still see an unclipped sine wave).

however, I have heard that some amps perform better at higher input voltages.

to measure current, you'd need a shunt. I don't know much about them but basically all I know is that they do something so that it enables you to measure higher amounts of current than a normal DMM can do by itself.

 

[yeshewa 10+ year member]

as far as head unit voltage goes....all headunits **** you will never get enough from a head unit personally i think all systems should have line drivers

 

[supa_c 5,000+ posts]

10V line drivers !

 

[helotaxi 5,000+ posts]

i think all systems should have line drivers

I think all people should learn to match components and set gains. Line drivers are a waste of money if the above is done correctly.

 

[jellyfish420 10+ year member]

I think all people should learn to match components and set gains. Line drivers are a waste of money if the above is done correctly.

what do you mean by match componants?

 

[Scarenius 10+ year member]

Personally, I'd just cobble your setup so you can run high input into low input. Hee.