Line Driver

[argenis69 4]

Hi SSA,

1- I want to know what's a line driver specifically for?

2- Also is it worth having?

3- I've heard that the higher the voltage the better, but I don't really know what is meant by that. Please explain.

4- I have an Audiocontrol Eql concert series, does this have a line driver?

My hu is a Jvc KD-R730BT.

Thank you.

[Quentin Jarrell 671]

In laymen's terms an amp amplifies the signal going in to it. Your headunit may put out 2 volts where a line driver may put out 6 volts. Lets just say the amp is capable of amplifying that signal 10 times.

Now per the works of Mr Ohm voltage times the current going though a resistor creates power. The resistance of the resistor (speaker in this case) determines current flow. (Not going into that on this explanation)

Now a one ohm speaker will always pull the same amount of current (not getting into inductance not going there here). Lets just pick a easy rhetorical number and say a one ohm speaker will allow 10 amps to go through it.

Now the amp hooked to the radio turns that 2 volt signal to 20 volts coupled with the current flow of the one ohm speaker you get 200 watts.

Now the same amp hooked to the line driver turns that 6 volt signal to 60 volts coupled with the current flow of the speaker you get 600 watts.

But all amps have "gain adjustments". This adjustment is there to compensate for the voltage coming from your source. Most amps will work from say .5 volts up to 10 volts. So you just adjust it so the amp puts out rated power. Which is directly related to the voltage it puts out and the resistance of the speaker. Bc a 1 ohm speaker will allow more current than a two ohm speaker the amp doesn't have to multiply that voltage as much to achieve the same output power. (Remember voltage x current = power)

Now amps can only multiply that signal so many times. So if the amp will only put out 600 watts at one ohm (the 60volts x the 10 amps) but you want 1,000 watts to ur one ohm speaker the I ly way to get there is to increase voltage. So you use the line driver to bump the input voltage to 10 volts which the amp multiples to 100 volts. However the amp can't accurately handle 100 volts (akind to hooking a 110 volt toaster to 220 outlet) so it puts out clipped signals or could be destroyed.

So, to answer the question a line driver is only needed when your input voltage is so low that it falls below the range of the amps "Gain adjustment". Which is normally so low that a line driver is not needed.

[95Honda 486]

The primary purpose of the line driver is to keep you line voltage up by sourcing more current.  Not needed most of the time...

[Impious 1,476]

There are only 3 situations in which a line driver is needed. 

 

1)  When you are using a very low preamp voltage source (such as an MP3 player) and it's output is below the level necessary to drive the amplifier to the necessary power levels.  Almost any headunit on the market will have sufficient output voltage to drive almost any amp on the market to full power output. 

2)  When you have unavoidable noise induced into the system during signal transmission and you need to boost the signal to increase your signal to noise ratio (this will be very rare)

3)  When you have a low voltage headunit and the amps makes an unacceptable amount of thermal noise with the high gain setting (though this is more a fault of the amplifier than the signal voltage level)

 

That said, line driver is sometimes a generic term and a product that features a line driver will something also offer other useful features such as equalization.  But that's a different situation entirely.  My comments above were specifically in regards to the line driver feature.

[argenis69 4]

Thanks guys.

[StreetLegal 119]

Perfect example of how questions should be asked, just look at the responses, they speak volume !!!

[jonbearsmt 919]

to expand on this topic i will be doing some testing this week....

 

 i am chasing DBs at this point, i will do some testing to get a base score, then i will add a line driver that i have laying around to see if it helps at all...

 

 daily i dont see a use fore it, but in chasing number  like i am it may just help a tad,. i dont plan to see huge changes as my head unit it 4 volt output, and my amp only expects 6 volts.. and my driver is a 7 volt boost.

 

 

 anyway if you would like i can come back and share my findings... but they would be strictly SPL related.

[Julian 641]

When I've ran more than 2 + amps I've always usually had to run a Line driver just due to the fact I'd have to turn up the gain an insane amount to get it to get loud without introducing a bunch of noise

[argenis69 4]

Sure, I'll check on the results.Thanks.

[Impious 1,476]

to expand on this topic i will be doing some testing this week....

 

 i am chasing DBs at this point, i will do some testing to get a base score, then i will add a line driver that i have laying around to see if it helps at all...

 

 daily i dont see a use fore it, but in chasing number  like i am it may just help a tad,. i dont plan to see huge changes as my head unit it 4 volt output, and my amp only expects 6 volts.. and my driver is a 7 volt boost.

 

 

 anyway if you would like i can come back and share my findings... but they would be strictly SPL related.

you can clip inputs just the same as you can outputs. Keep that in mind when running and reviewing the results of your test.

[jonbearsmt 919]

to expand on this topic i will be doing some testing this week....

 

 i am chasing DBs at this point, i will do some testing to get a base score, then i will add a line driver that i have laying around to see if it helps at all...

 

 daily i dont see a use fore it, but in chasing number  like i am it may just help a tad,. i dont plan to see huge changes as my head unit it 4 volt output, and my amp only expects 6 volts.. and my driver is a 7 volt boost.

 

 

 anyway if you would like i can come back and share my findings... but they would be strictly SPL related.

you can clip inputs just the same as you can outputs. Keep that in mind when running and reviewing the results of your test.

will do