Preamp Voltages

[zaxfire69]

As of right now..I will probably be over the limit...I have 5 volts output on my H/U plus I have my Old School Phoenix Gold Line Driver..Will probably take the line driver out..Cause 5 volts should be plenty...I will test it and see..Gains on amp way down...I still have to get my amp back first off...

[audiofanaticz]

higher voltage is better for noise reduction ???

Im not really sure on that, would like to find out.

But this is why Im so anti-line driver. Why spend the extra cash on a line driver to boost your signal up so high to run your amp at a lower gain setting that WILL NOT make your amp more effiecent, last longer, or be "louder". Only time a line driver was ever useless was back in the old school audio when you ran multiple amps off of "rca Y splitters" which cuts down your preamp voltage drasticlly everytime you splice another amp in off of the one rca cord. So if you where running multiple non strappable,master/slave,or amps without rca pass throughts (such as a rca input and rca output), or you have a very old or cheap headunit, such as jensen for example is when you would benefit from a line driver. But then you still have to look at it as would you rather spend money on just a line driver, or would you rather spend a little more money and buy a eq or a crossover that will not only boost your preamp voltage, but will give you better audible control over your stereo to make it better.

Your gain is not a volume, it is to be used to match it to your preamp output voltage. Thus if every amp ran a standerd volt preamp output (lets use 4 for example) then any and every headunit you buy would be 4 volt, and there would be ZERO need for a gain on your amp unless you just wanted to be that guy and clip your shit

And if you use this site http://www.subwoofertools.com/forum/setgain.asp to properly set your gain with a dmm you should have no problom with clipping. Weather you have 2 volt preamp outputs or 6 volt preamp out puts your gain will be set correctly.

Example your amp is 3000 watts rms at 1 ohm. you type those two numbers in and click on "figure target voltage". It then says that my target voltage is 54.8 volts. With the digital multimeter hooked up to your amp, you start to turn your gain up until you see 54.8 pop up on your multimeter display. Now if your deck has 2 volt preamp outputs, your gain will be turned up farther then it would be if you had 6 volt preamps. Again your amp will not be clipping or working harder then needed be.

As of right now..I will probably be over the limit...I have 5 volts output on my H/U plus I have my Old School Phoenix Gold Line Driver..Will probably take the line driver out..Cause 5 volts should be plenty...I will test it and see..Gains on amp way down...I still have to get my amp back first off...

Maybe the reason your soft turn on does not work no more on your amp if it received too high of a input voltage. Your best bet would be to call up american bass and ask them the max input voltage the amp can take, although Bob (if I remember right) is somewhat hard to understand.

[pstone11]

cool.. totally more educated on that now... I guess I was under a false impression about that one.. I thought that the higher the gain was, the harder the amp had to work to boost the signal, resulting in a little more energy/heat spent. Right on man...

[audiofanaticz]

cool.. totally more educated on that now... I guess I was under a false impression about that one.. I thought that the higher the gain was, the harder the amp had to work to boost the signal, resulting in a little more energy/heat spent. Right on man...

The only way your amp is going to work harder is if your amp gain is set to high and you are clipping, you can clip your amp with high or even low preamp output voltages. Otherwise your amp will work just as hard as it did with the higher voltage preamp outputs.

Thats why the best way to tune your amp is using a O-scope, because you can visually see your amp when it is clipping on a screen, but a dmm is the next best thing. Some people say they can tun their amp by sound, this maybe somewhat true but in all honestly you wont hear your amp clipping unless it is clipping alot and very bad. But the o-scope will allow you to tune your amp(s) to their max limit without any clipping.

If your amp is designed to push say 3000watts rms at 1 ohm, it shouldnt get hotter then the normal temps that it normally plays at if everything is set correct. When your amps are getting so hot that you cant touch them and you are running them at the correct ohm that the amp is stable at you are more then likely clipping the shit out of your amp, which makes it hot, and the heat is making the amp less efficient, drawing more amps, and giving you less wattage.

In the image below, the yellow line indicates the max power your amp can produce without clipping. When you clip your amp you get the white square looking line. Using a oscope you will be able to see these lines and set your amp properly and not just turning the gain til you think its loud(er)

[pstone11]

Right on, I get all of that stuff... So, you can call the gain knob a little built in line driver.

Couple questions then..

So say you have a amp with a 4volt input... Throw a 10 volt line driver on that amp only... What is the bad news?

Why do they still make line drivers with 3 in/3 out 10 volts a piece?

[audiofanaticz]

Right on, I get all of that stuff... So, you can call the gain knob a little built in line driver.

Couple questions then..

So say you have a amp with a 4volt input... Throw a 10 volt line driver on that amp only... What is the bad news?

Why do they still make line drivers with 3 in/3 out 10 volts a piece?

well on a amp with a 4 volt input and your giving it 10 volts, if the amp cant handle that much of input voltage you could end up frying the amp, or just some parts. I think this maybe of what happened to zaxfires amp because his amp still works, but he does not get the soft turn on/off and makes a big thump.

Most line drivers are adjustable for how many volts you send out of the line driver to your amp. So unless your line driver is maxed out on the dial it wont be sending out the 10 volts.

If your amp is working fine now, it may not last.

But hey, Im no pro. I just research as much as possible so I dont mess up my gear. IMO a line driver will help you fry your gear quicker because you maybe clipping your gear just the slightest and not even notice it. Over time you will fry one thing or another. However some amps can take a high input voltage like the hifonics xxv coloussus which takes up to 9 volts.

My buddy had one of our friends hook up his stereo in his car, it consisted of a clarion touchscreen hu, two dd 3515s dvc 4ohms, and a audiobahn hct2300 amp (2400wrms it claims). Even at low volumes the red led kept flashing on the bass knob. It illumantes red when the amp is clipping, otherwise it should be blue. Well what my friends tried telling me was it was meant to blink red to the beat, I even showed them in the manual for the amp, but they said that both I and audiobahns manual was wrong. Well I turned down the fully maxed out gain and bass boost a few times, but somehow those 2 things always ended up maxed out over and over, I gave up on it. The amp took a crap about 2 months ago, it still plays and you can kinda hear the subs, but there is no volume to the amp at all no matter how the settings are on the amp.

What do you think happened to the amp? I think that the constant clipping caught up to them.

As for the 3in/3 out 10 volt line drivers. depending on which ones Im not sure.

But

Let me answer your question with another question.

Why do they still make capaciters when we all know they hurt your current flow more then they help?

Answer: To make money.

Lets use the AudioControl Matrix line driver. 6 channel 10 volt line driver.

http://www.carsound.com/reviews/processors/matrix.html

The Matrix met or exceeded all of its published specs, but the important issues are the source impedance of 49 ohms and nearly 10 volts of clean output. That makes it Mr. Line Driver to you, and you’d best smile when you say it, son. AudioControl claims that this beast will drive up to seven amps per channel — that makes a total of 42 potential amps if I can still multiply. With a source impedance of 49 ohms and a typical amp input of 20K, we figure the number would be more like three dozen channels per output — but what’s the difference once you get past seven? On the other hand, if those SPL guys find out that they can drive 200+ amplifiers with this thing, they might just be crazy enough to try it.

So maybe that will explain why the make multichannel high volted line drivers. As I said before, for running multipable amp setups without having to use RCA Y adapters which cut down the signal voltage drasticly everytime you add in another Y splice.

When I bought my car it came with a somewhat decent audio system. It also had a AudioControl Overdrive line driver. When I put my stereo in the car I tried out the overdrive line driver. I had my car tuned with a oscope and then metered with the line driver, and then disconnected the line driver, retuned the amp again and then metered again. During the tests I played a solid 50hz bass line and volume 28 on my alpine. Never changed any settings on my deck for either test not even the volume. Now the mic was a audiocontrol ftl which hasnt been calibrated in I dont know how long and was a easy 15+db's over, but it gave me an idea on weather or not to use the line driver.

The results are below:

Line driver not being used. I also tryed using a 1.0 fared rockford cap that came with the car to stabalize the voltage to my 4 channel amp which was also a big let down.

[zaxfire69]

I let the fellow who is trouble shooting my amp know that I probably over volted my inputs...Man thanks for that info..The line driver is not needed now that I have 5 volt outs...Also when my amp gets back this time i will have an Oscope to set gains by..That is for sure...Thanks for all your info I am going to have to remember this thread..I will favorite all the links you gave when I get back home from work...

[thumper02]

ok, I got to agree with all of that accept for the part where it goes like "this = happier more efficient amps = happier me".

How is the amp working more efficient? Your amp is still putting out the same power while having the gain turned down more becuase your new HU has higher volt preamp outputs.

If you have your gain set correctly with a o-scope, or even a dmm, your amp will work just as hard as it did before to make its wattage with either a higher gain setting for low volted preamps, or a lower gain setting for higher preamps.

All a headunit does with higher volt preamp outputs does is make it so you dont have to crank your gain up high. BUT turning your gain up high WILL NOT hurt your amps if your headunit does have low volted preamp outs like pioneer does AS LONG AS YOU SET YOUR GAINS CORRECTLY.

I have a funny feeling that this is why Pioneer does not stress the high volted preamp outputs because it dont pay to stick extra money into something that does not matter.

wow that was preatty dumb of you to say because the best spl guys in the world strees on deck out put getting the highest they poss get

[zaxfire69]

I am just about sure that is what happened to my amp..I was running roughly 10 Volts through the inputs..Considering that my PLD-1 was outputing 8volts and my crappy Sony was at least 2 volts...I won't be using it this go round..