View Full Version : How Important is Voltage?

12-24-2012, 09:37 AM
I was curious how important the head unit voltage is. I will be running amps for my system and I was always under the impression that the head unit needed to be 4 volts. However, when I brought this up to my local shop, he said that wasn't important because he had in line stuff he would add that brought the voltage up. Is he on the right track with this or do I need to spend the money on a 4 volt head unit?

12-24-2012, 09:41 AM
Low voltage headunit and a line driver or a high voltage hu by itslef. Either will work just fine and he is correct

12-24-2012, 09:42 AM
witha 4v preout unit obviously your amps will see more signal and therefore you wont have to turn gains up as hhigh etc.. amp will run more efficiently

and yes you CAN buy a line driver or a eq that boosts preout voltage.. but MOST amps cant go above a 5v input signal anyways..
so by the time you buy a cheap 2v preout headunit AND go buy a eq or a line driver it will cost more than what a good 4v would cost in the 1st place
you can get a refurb 4v pioneer on ebay for around 100 110bux shipped

12-24-2012, 10:03 AM
4V will allow the amp to run cleaner generally, but that's what the gain knob is for, to adjust for different pre-amp voltages.

12-24-2012, 11:41 AM
Please do a search of 2V vs 4V preouts, it's been covered here many times. And adding a line booster just adds another link in the chain that you don't want.

12-24-2012, 11:44 AM
its important..especially for me due to having to run a factory deck..so im running a audio control unit that also is a 8v line driver

12-25-2012, 12:08 PM
If he's planning to add an in-line, should I go with that or spend the extra money on one with 4 volts? I'm looking at one of the Pioneer dual dins, just not sure which one yet. He was trying to talk me into the AVH-X3500BHS because I have satellite radio.

12-26-2012, 09:51 AM
HU's with 4V preouts tend to be higher end with more features and better SQ. There's a lot more to a deck than just preout voltage. I would definitely go that route given a choice. And there are very few cases where a line driver is needed - there's plenty of SQ installs out there with 2V preouts.

12-26-2012, 10:40 AM
The only reason for a high level output preouts is to lower the noise ceiling of your amplifiers -Aka if you have a noisey or unshielded power supply it allows you to lower the gain thus eleminating the extra noise.

12-26-2012, 10:45 AM
I've never been happy with 2volt decks with multiple amps... I would go for a 4 volt....

12-26-2012, 11:10 AM
Ya go with a nice HU thats 4v or better.