Pre Amp Voltage

[Mike75 10+ year member]

How important is pre amp voltage? What does it really do?...For example, on the Alpine units, they are all 2 volts, until you get to the 9855, and a couple others...What would be the difference in sound between a 2 volt unit and a 4 volt unit?...Is it worth the extra money it requires to get 4 volts?.........Is there any other spec that is significant when choosing a head unit? (when you won't be using the head unit's amp)....Thanks

Click to read more...

 

[Mike75 10+ year member]

I really meant to post this in the Head Unit section, so if someone could move it there, that would be great..Thank you

 

[Nightfall 10+ year member]

My understanding would be that it would be a little louder, but i'm a n00b.

Hook a portable CD player up to an amp with a 1/8" DIN to RCA's. When you increase the volume (mV, I believe) on the CD player, the volume on the speaker(s) connected to the amp get louder. Wrong thinking?

 

[Mike75 10+ year member]

lol, I have no idea what you are talking about....Thank you though

 

[Ignatowski 5,000+ posts]

4v and or more is worth the extra money to me

I wont even mess with 2v HU's in my car..

The newer Alpines are mostly 2v except for a few higher end models

which IMO stinks,as reason why I dont bother with them anymore..

Many other HU companys are offering more voltage,better SQ and same or more features for less money...Alpine is getting lamer every year

 

[stratusrt01 10+ year member]

Definately worth the money to upgrade. I upgraded from a 2V deck to 8V, and couldn't be happier that I spent the money.

 

[djman37 5,000+ posts]

say you want 24v output from your amp.

with 2v max outputs 24/2=12 12x amplification at least.

4v is 6x amplification, getting better(cleaner)

Things like the Eclipse with 8v unclipped outputs will yeild at least 8v measured around 10v at times....just around a factor of 2-3 for amplication.

Amplifier input votage range comes into play also.

If you can turn off the internal amp on the HU this helps clean up the signal too.

What it boils down to is more accurate output. Less interference introduced since the signal changes less, any variations introduced won't be amplified as much.

That's pretty basic, but http://www.bcae1.com can do a much better job w/pictures.

 

[FoxPro5 5,000+ posts]

say you want 24v output from your amp.with 2v max outputs 24/2=12 12x amplification at least.

4v is 6x amplification, getting better(cleaner)

Things like the Eclipse with 8v unclipped outputs will yeild at least 8v measured around 10v at times....just around a factor of 2-3 for amplication.

Amplifier input votage range comes into play also.

If you can turn off the internal amp on the HU this helps clean up the signal too.

What it boils down to is more accurate output. Less interference introduced since the signal changes less, any variations introduced won't be amplified as much.

That's pretty basic, but www.bcae1.com can do a much better job w/pictures.

Well said. I will say this, with any of the 8v Eclipse I have used, I have not been able to turn the gains up on my amps very much at all before the signal starts to clip. Which roughly translates into cleaner, stronger amplification of the signal = better sq.

 

[Mike75 10+ year member]

If the amp has plenty of power though, (more than is necessary for the specific speakers) then does the pre amp voltage still matter? Does it still make better SQ?.....The reason I ask this is because I thought that the higher pre amp voltage the better SQ....I read someone's sig on here, and it was Dispelling Myths and on the list of things I thought were true for years, this was one of the items on there...It said something like it didn't matter, I don't remember...

 

[Nightfall 10+ year member]

If you took two decks that had two different pre-out voltages and played the exact same subs in exactly the same box tuned exactly the same in the exact same car at the exact same dB level with the exact same song, I doubt you could tell. If that is what you are asking.

 

[MrBlack 10+ year member]

The major benefit of feeding a higher voltage signal into your amplifier is that it allows you to set the voltage gain lower on your amplifier, thus giving a cleaner signal through to your speakers.

But as long as you're running a clean signal to and from the amplifier and everything is set properly, I doubt anyone here could hear the difference between a gain matched system that was fed a 2v signal or a 4v one. Back in the day, anything above 500 mV (1/2v) was rare, and you could still get a clean signal, although at times it could be challenging.

 

[iceteebone 5,000+ posts]

the gain on an amp is used to match the output of the deck. if you get noise by turning your gain higher for a 2 volt deck, then you have install issues. it is a myth that higher volts are better. look for low impedence, non-clipping rca's

 

[lrgaslife 10+ year member]

Look at it this way.

Your rca cables is what carries your signal from your deck ALL the way to your amps or crossover or whatever. Even in my Civic, that is pretty far. So if you are contenplating over a 2 to 4 volt increase. That is twice the power of the signal. If you are serious enough about your sound to actually be thinking about it (that is why your are on this forum) then you just need to do it. A more powerful signal means less chance for signal loss or distortion in transit from point A to B. If your head unit is one of the most inportant parts of your system then your signal voltage is a main function in that unit.

DONT THINK LOUDER

THINK CLEANER

 

[FoxPro5 5,000+ posts]

If you look at the gain knob on your amp (which is really a sensitivity adjustment) you will notice that less gain = higher number and more gain = lower number. Lets say for example that your amps input sensitivity is 200mv - 8v and you head unit is 4v. Then you would need to the knob from 8v clock wise towards 200mv until they match.

Just because your amp has a lower input sensitivity than another doesn't make it better. The Arc XXK line, for example, have imput senitivites of around 2.8v max. The Zapco competition line have input sentivities up to 16v (although the C2K amps do accept balanced imputs - which is another issue). Both are awesome amps!!

 

[DBfan187 5,000+ posts]

Keep in mind that these preout voltage rating can only be obtain at or near full volume with 0dB material.