update - how important is the pre-out voltage?

[ant the ninja]

Not to threadjack but I keep my sub level on zero (goes up to +6 or +12, cant remember) If i put it all the way up, does that make my preout-voltage go up? I know i have 4volt preouts, am I giving it 0 volts right now? Or am I misunderstanding this whole thing?

[J-Lane]

Here is a short opinion about PreAmp output voltage from another web site.

Pre-Amp and output voltage - By Eddie Runner

Pre amp is usually the control center. Your volume control, tone controls, EQ (if any) and source switching is usually at your pre-amp. The Pre-Amp is designed to be a very clean low signal voltage and take care of any signal modifications you might want to make to the signal (music) BEFORE the signal goes to the amplifier.

Pre-amp signal is usually LOW, it was designed to be low so there is less distortion at this stage. Home pre-amps usually operate with about 1 to 1.5 volts of output, the idea was to keep the voltage down as low as possible to keep the distortion down as low as possible in the pre-amp stage and then after the signal leaves the pre-amp we let the amplifier do what it does best.

In car audio we have used this very low level for years with pretty good success. But in many cases in car systems there might be some noise. Some of the car stereo manufacturers have stepped up the output voltage of their headunits in an attempt to help us have a noise free system.

Installers have always found that certain types of noises in a car system can be reduced by turning down the amplifier gain controls. But far too often the customer gets his system fairly noise free but with no gain!! The system just may not play loud like it should if the gain controls are turned down too far. Turn the headunit all the way up and it still wont get loud. This is where the manufacturers come in with the higher level headunits! Now you can turn them higher, even when your gains are very low (and hopefully any bad noises are also very low)...

Some purists find this added amplification (and distortion) on the headunits appalling. But most of us cant really hear the added distortion and find it much better than the noise !!!

Some rookies find the added headunit voltage an advantage cause now they think their amp will play louder! NOT TRUE! The amp will still have its maximum output power and it will not change in most cases of the amps max drive can be achieved. Many rookies compare a 1or 2 volt headunit with a 4 to 8 volt headunit and they only notice that with the higher voltage the system gets loud at 10 (on the volume scale) and you used to have to turn it up to 30..!! Some rookies are fooling themselves into thinking this is GOOD! This is better!! But it may not be.

Ideally, a system has a good swing to the volume control... Too much signal voltage into the amp the system will get loud too soon on the volume swing. Not enough signal voltage to the amp and they system volume control can go all the way up and not get loud like you might like it. Setting the amp gain controls correctly will give you this proper swing!

And the rookies may not know it, but if they set the gain controls correctly with a low signal output headunit and compared it to a high signal output headunit then there would be NO volume difference anywhere in the system volume swing...

But I still hear them say, "WOW, I got a 5 volt headunit!, it sure plays louder!, its worth the money!"

I just shake my head in amazement...

Basically if you have any "electrical noise" in your setup a lower preamp voltage will cause you to have to set your gain at a higher level thus increasing/amplifying the noise. If you have a higher pre amp voltage you will not need to set the gain as high. Whenever possible use an o-scope to set your gain.

[Winn]

Is there a voltage booster I can get or something?

It's still getting signal and hits pretty hard...

why do they sell me $600 worth of stuff and not tell me that it's going to sound like shit cause of this or that.....

I believe its called a "STEPDOWN". it boosts the volts. Thats what i had to do for my girlfriends car so i could use the default manufacturer head unit and it works fine. i believe i might not be totally sure though.

And they bulls**t to take your money they give you sh*t competition subs where i live for 1000$ its complete bull s**t Get Fi for the same price and you will be amazed

[dugee81]

Not to threadjack but I keep my sub level on zero (goes up to +6 or +12, cant remember) If i put it all the way up, does that make my preout-voltage go up? I know i have 4volt preouts, am I giving it 0 volts right now? Or am I misunderstanding this whole thing?

if its "bass boost", keep at 0

if your HU has a sub RCA out & it has a "sub level" then i would say turn that all the way up.

you probably are giving it more than 0 volts, but not the full 4

[casemods]

My head unit has only one RCA preout

My amp has 2 inputs

Should I split the one line into 2?

[OrionStang]

Your description of your H/U says it has 3; front, rear, and subwoofer.

[General]

you could get a line driver but i dont think thats the issue. most amps can perform with as little as .2 volts of preamp voltage. A higher preout voltage juts means your amp isnt going to have to work as hard to deliver the power. That means you dont have to crank the gain out. Id think if you actually bought a quality head unit and not some third world country equivalent you'd be a little happier. I tend to stick to the big guns for head units. alpine kenwood panasonic eclipse pioneer clarion etc.

So true!

I agree 100%

Sounds like you bought yourself a cheapass headunit (with 3 rca output in the manual, but just 1 rca output in real life).

[casemods]

Oh sorry I meant it only has one cable for the AMP pre out....not left and right.....

[Mr. Darkjustice]

Oh sorry I meant it only has one cable for the AMP pre out....not left and right.....

you mean its a mono subwoofer preout? thats not that rare. not using both sides of your rcas will split your signal, unless your amp has mono inputs. a y splitter fixes it otherwise

[OrionStang]

you mean its a mono subwoofer preout? thats not that rare. not using both sides of your rcas will split your signal, unless your amp has mono inputs. a y splitter fixes it otherwise

Yeah, kinda how my amp has only one input rca. I just use a 2-female to 1-male y splitter, which is what you'll need coming off the deck.