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View Full Version : What kind, and how much of a difference would i notice with 2v , 5v, or 8v preouts??



BlkonBlkFG
10-30-2006, 05:28 PM
Just like it says, what kind and how much of a difference would I notice going from 2v to 5v to 8v preouts?? Right now my deck has 2v preouts, and i'm wondering if its worth it to sell it and get a unit with either 5v or 8v preouts. Is it?? Would you notice the difference from 5v to 8v??

iceteebone
10-30-2006, 05:29 PM
none at all. proper gain setting is all you need

BlkonBlkFG
10-30-2006, 06:02 PM
I have "heard" that with a higher preout voltage that the amp wouldnt have to work as hard, and that I would get a stronger and cleaner signal which would make it louder. Is there any truth behind what I've "heard"?

iceteebone
10-30-2006, 06:05 PM
I have "heard" that with a higher preout voltage that the amp wouldnt have to work as hard, and that I would get a stronger and cleaner signal which would make it louder. Is there any truth behind what I've "heard"?

nope. what it does is if you have a higher input voltage, you don't need to turn up the gain, and therfore less chance of hearing induced noise. if you have induced noise, higher voltage preouts are just a bandaid to the problem

Daher2323
10-30-2006, 06:05 PM
when i switched from 5v to 8v preouts..my bass was noticably louder....i mean alot. this switch was from a panasonic to an eclipse unit though so it could have just been much better quality unit. I'm sure with proper gain setting, you wont notice much difference if they are both good hu's

BlkonBlkFG
10-30-2006, 10:53 PM
So it is easier on your amp then, b/c then you dont have to turn your gains up as high? I set my gain on my amp based off of the formula SQRT ( RMS * ohms)....turned my volume up to 28 (80%) and adjusted to the voltage i figured. Also did the same for my subwoofer and sounds like I have no bass at all, it *****. So I was wondering if that stronger signal would make that much of a difference.

xploit2
10-30-2006, 11:09 PM
Ok now what kind and how much of a difference would I notice going from 55ohms indepence from an eclipse unit and a 100ohms indepence in a pioneer unit.

BlkonBlkFG
10-31-2006, 08:33 AM
Bump to the top......what kind of difference are we looking at guys with different preout voltages?? It seems different people have different opinions, what are the facts here??

djman37
10-31-2006, 08:47 AM
when i switched from 5v to 8v preouts..my bass was noticably louder....i mean alot. this switch was from a panasonic to an eclipse unit though so it could have just been much better quality unit. I'm sure with proper gain setting, you wont notice much difference if they are both good hu's

the brand change and settings accounted for bass increase, IF you played the same track.

amplifiers to exactly what they are called, amplify the input signal.
Say you want 100v output, so you're different decks output 2v, 4v, and 8v.

100v= 2v * 50
100v= 4v * 25
100v= 8v * 12.x

the 8v deck causes the amp to make less of a change. If induced noise is always a very small number, say .1% of that signal, the more you increase that signal the 'louder' that noise will become as well.

cliff notes: higher input voltage = less amplification of the BAD and the GOOD signal.

No noise to start with = no problem with low voltage inputs.:D

iceteebone
10-31-2006, 10:28 AM
So it is easier on your amp then, b/c then you dont have to turn your gains up as high? I set my gain on my amp based off of the formula SQRT ( RMS * ohms)....turned my volume up to 28 (80%) and adjusted to the voltage i figured. Also did the same for my subwoofer and sounds like I have no bass at all, it *****. So I was wondering if that stronger signal would make that much of a difference.

the stronger signal would just mean you don't turn your gains as high.

Flipx99
10-31-2006, 10:32 AM
the stronger signal would just mean you don't turn your gains as high.

I think his question is "Does gain level cause the amplifier to work harder/harder on the amp/ etc"

BlkonBlkFG
10-31-2006, 05:03 PM
Well right now I have the Alpine 9857 and to me it sounds pretty good. I have a memphis m-class MCA300.4 interior amp and have the gains set a little over half way to get my calculated voltage. Alpine of course has the 2v preouts...so would it be smart of me to sell that headunit and get one with a 5v or 8v preout, or should I just leave it since it sounds pretty clean to me right now? Will the sound be a lot cleaner if i was to go with an 8v preout HU ? Thats mainly what i'm trying to get at.


So really theres nothing wrong with low voltage preouts as long as its a clean signal? Am i following this correctly?

GrnEydDvl
10-31-2006, 05:10 PM
I think his question is "Does gain level cause the amplifier to work harder/harder on the amp/ etc"

No. It does not. It works just as hard - assuming the gains are matched properly for whatever voltage you are using at the time.

As said earlier - there is no real benefit from using higher voltages aside from not amplifying the noise floor as much.

BlkonBlkFG
10-31-2006, 10:22 PM
So basically it sounds like I should just stick with what I have. EH??

Notwerk
10-31-2006, 11:40 PM
If your only reason to switch is the input voltage, then yes, stick with what you have.

AJē06
11-01-2006, 03:09 AM
Bump for a goood question

BlkonBlkFG
11-01-2006, 07:52 AM
It seems that when you have a higher preout voltage that you usually can turn the HU all the way up without it clipping...hence getting more out of your speakers and amplifier. Right?

mlstrass
11-01-2006, 11:19 AM
Here's my experience, take it for what it's worth.

Built a sealed Tempest running off a PG amp with 500 watts. Sounded very good in my car. Excelon HU with 4.5v pre-outs.

Put it in the GF's car and the bass was GONE. Pioneer HU with 2v pre-outs. Turned the gain up all the way, still not much bass. Also noticed the Polk coax's didn't sound very good and they're amped.

Long story short, her HU has 3 levels of loudness and I had to use the MID one to get back the missing bass and make the speakers sound full and loud.

There seems to be more to it than "just match the amp gain to the pre-out", at least in this case there was as everything sounded like crap compared to running off of my HU.

iceteebone
11-01-2006, 11:53 AM
It seems that when you have a higher preout voltage that you usually can turn the HU all the way up without it clipping...hence getting more out of your speakers and amplifier. Right?


gains are made adjustable so they can match the input voltage of your headunit. all source units will have different output voltages, meaning you have to adjust the input voltage, to match the output voltage of the source unit


Here's my experience, take it for what it's worth.

Built a sealed Tempest running off a PG amp with 500 watts. Sounded very good in my car. Excelon HU with 4.5v pre-outs.

Put it in the GF's car and the bass was GONE. Pioneer HU with 2v pre-outs. Turned the gain up all the way, still not much bass. Also noticed the Polk coax's didn't sound very good and they're amped.

Long story short, her HU has 3 levels of loudness and I had to use the MID one to get back the missing bass and make the speakers sound full and loud.

There seems to be more to it than "just match the amp gain to the pre-out", at least in this case there was as everything sounded like crap compared to running off of my HU.


apples and oranges. too many variables :) remember the scientific method

heyman421
11-01-2006, 12:10 PM
only difference you will see is a decreased chance of seeing any ****** in the next few months, cause you spend all your money on a headunit to have 3 extra volts of preamp line-voltage.

BlkonBlkFG
11-01-2006, 01:42 PM
No matter how much I spend on whatever I buy, I will always see plenty of ****** :yumyum: . Anyways, I'm trying to decide if its worth it or not. Is a couple extra volts or different HU gonna make everythingsound better then it allready does, or is there gonna basically be no difference?

xploit2
11-01-2006, 02:08 PM
I doubt that there is No difference. the difference in SOUND is very noticeable going from 2V to 5V.

Rochambeau
11-01-2006, 02:11 PM
******... Is that a new Blaupunkt HU? :D

dgr00s
11-01-2006, 02:22 PM
going from 2 to 5 the sound difference was very impressive to me, going from 5 to 8 wasnt as noticeable.

BlkonBlkFG
11-01-2006, 02:41 PM
exactly what I thought...see, the truth comes out. So we've come up with 2v to 5v is a huge difference and 5v to 8v isnt very much of a difference. So its sounds like it would be a good idea to maybe get a HU with atleast a 5v preout.


Any others??

heyman421
11-01-2006, 02:49 PM
The reason i have a hard time believing it's that noticeable of a difference is because that's the absolute PEAK output.

The pre-amplifier output voltage isn't even rated as RMS or MAX, so it's most likely MAX

It also doesn't specify if that BEFORE the output actually clips, or at full tilt.

AND most head units don't even tell you what resistance those numbers are presented at.

So if one brand rates their outputs at MAXIMUM output, at completely clipped FULL TILT, and another brand rates theirs RMS, with the HU volume at a reasonable, unclipped level, then they'll be two completely different numbers, and there's NO provisions for explaining the conditions for the measurement in the specifications, so you REALLY don't know WHAT you're looking at. They may as well be 2 completely imaginary numbers that someone made up.

BlkonBlkFG
11-01-2006, 03:18 PM
Thats true....Alpine states on their website that their preouts go up to 2v, and then anything after that it will start clipping. So how do you know once you've reached your 2v limit??? How do you find that out?

xploit2
11-01-2006, 03:51 PM
Thats true....Alpine states on their website that their preouts go up to 2v, and then anything after that it will start clipping. So how do you know once you've reached your 2v limit??? How do you find that out?


read the HOW TO SET THE GAIN sticky in the amplifier section. u will find your answer there

BlkonBlkFG
11-01-2006, 05:47 PM
Oh ok...allready done then. SQRT(RMS of amp x load)....then turn everything flat and turn your volume to 80% of the maximum. Play a 0db 1khz tone and adjust your gain until you get the voltage you calculated. Right??

xploit2
11-01-2006, 06:39 PM
Oh ok...allready done then. SQRT(RMS of amp x load)....then turn everything flat and turn your volume to 80% of the maximum. Play a 0db 1khz tone and adjust your gain until you get the voltage you calculated. Right??


yes sir!.. thats you answer. :)

the727kid
11-01-2006, 07:03 PM
I will let you know tommorow when I go from 2v in a Pioneer to the CD5000 8volt.

BlkonBlkFG
11-01-2006, 07:45 PM
that would be perfect if you could....i was actually lookin at picking up the CD8445...eclipse with 8v preout 55ohm resistance.

heyman421
11-01-2006, 07:47 PM
if you have your gains set per the gain setting manual, see how your gain settings change with the new headunit

i'd be interested to see

the727kid
11-01-2006, 07:53 PM
I'm see how it is now and then set them gains to JLs accordance numbers (prob end up bumpin them down 6v) and I'll let you know.

squeak9798
11-01-2006, 08:48 PM
I doubt that there is No difference. the difference in SOUND is very noticeable going from 2V to 5V.

Completely false.

There is no difference in sound.

squeak9798
11-01-2006, 08:48 PM
Just like it says, what kind and how much of a difference would I notice going from 2v to 5v to 8v preouts??

Assuming there is no audible noise with the 2V setup, then you will hear zero difference.

squeak9798
11-01-2006, 08:49 PM
I have "heard" that with a higher preout voltage that the amp wouldnt have to work as hard, and that I would get a stronger and cleaner signal which would make it louder. Is there any truth behind what I've "heard"?

Not true.

squeak9798
11-01-2006, 08:49 PM
when i switched from 5v to 8v preouts..my bass was noticably louder....i mean alot.

Then you didn't reset the gain correctly (if at all)

squeak9798
11-01-2006, 08:50 PM
So it is easier on your amp then, b/c then you dont have to turn your gains up as high?

The only difference would be if your amplifier had audible noise with a higher gain setting.

If it doesn't, then you will hear no difference and there is no difference in performance in your amplifier.

2kchevy06civic
11-01-2006, 08:50 PM
lol I was waiting for squeak to chime in.

xploit2
11-01-2006, 08:53 PM
well....the727kid let us know what you find out.

squeak9798
11-01-2006, 08:54 PM
Bump to the top......what kind of difference are we looking at guys with different preout voltages?? It seems different people have different opinions, what are the facts here??

The fact is that the only potential difference is an increase in the signal to noise ratio when going with a higher preout voltage. And, therefore, if you had no audible noise with a lower voltage...going higher is going to gain you nothing.

squeak9798
11-01-2006, 08:54 PM
I think his question is "Does gain level cause the amplifier to work harder/harder on the amp/ etc"

No.

squeak9798
11-01-2006, 08:57 PM
Alpine of course has the 2v preouts...so would it be smart of me to sell that headunit and get one with a 5v or 8v preout, or should I just leave it since it sounds pretty clean to me right now?

Do NOT change simply for preout voltage.

If you want to change, change for something worthwhile...such as "because the new deck has better crossover selection, more equalizer bands, etc"


Will the sound be a lot cleaner if i was to go with an 8v preout HU ?

Not if you have no audible noise right now.


So really theres nothing wrong with low voltage preouts as long as its a clean signal? Am i following this correctly?

Yes.

Some of the most highly respected "SQ" decks don't offer voltages over 2V...some have even been as low as 1V.

squeak9798
11-01-2006, 08:57 PM
If your only reason to switch is the input voltage, then yes, stick with what you have.

:word:

squeak9798
11-01-2006, 08:58 PM
It seems that when you have a higher preout voltage that you usually can turn the HU all the way up without it clipping...hence getting more out of your speakers and amplifier. Right?

That has nothing to do with the preout voltage, but rather the design of the headunit.

squeak9798
11-01-2006, 08:59 PM
Here's my experience, take it for what it's worth.

Built a sealed Tempest running off a PG amp with 500 watts. Sounded very good in my car. Excelon HU with 4.5v pre-outs.

Put it in the GF's car and the bass was GONE. Pioneer HU with 2v pre-outs. Turned the gain up all the way, still not much bass. Also noticed the Polk coax's didn't sound very good and they're amped.

Long story short, her HU has 3 levels of loudness and I had to use the MID one to get back the missing bass and make the speakers sound full and loud.

There seems to be more to it than "just match the amp gain to the pre-out", at least in this case there was as everything sounded like crap compared to running off of my HU.

Completley different cars, completely different setups, completely different headunits.

Hence, completely invalid comparison.

squeak9798
11-01-2006, 09:01 PM
going from 2 to 5 the sound difference was very impressive to me, going from 5 to 8 wasnt as noticeable.

Then you didn't reset your gain properly (if at all).

Or, you switched decks which means there are a thousand other variables at work (different settings, etc).

So, again, invalid comparison from which you can draw no conclusions.

squeak9798
11-01-2006, 09:02 PM
exactly what I thought...see, the truth comes out.

Don't take truth from misinformation.

You can't draw a valid conclusion from invalid experiments....i.e. comparing tens of variables at once....which is what those people saying "oh, I noticed a huge difference" are doing.

squeak9798
11-01-2006, 09:04 PM
I will let you know tommorow when I go from 2v in a Pioneer to the CD5000 8volt.

Completely invalid comparison.

xploit2
11-01-2006, 09:04 PM
Ok now what kind and how much of a difference would I notice going from 55ohms indepence from an eclipse unit and a 100ohms indepence in a pioneer unit.

can u answer this one squeaky :D

squeak9798
11-01-2006, 09:06 PM
Anyone with a single headunit can do the experiment themselves.

Anyone want to guess as to how one can run an experiment to compare differences in preout voltage with their headunit?

Time for Ghosthunters....so I'll let you all come up with the answer as to how this can be accomplished :)

squeak9798
11-01-2006, 09:07 PM
can u answer this one squeaky :D

In all honesty, you probably won't notice an audible difference <solely due to the preamp impedance>

heyman421
11-01-2006, 09:08 PM
ooh, ooh, i want to score squeak points!

do you reset your gains at different volume levels?!

DBfan187
11-01-2006, 10:14 PM
also keep in mind that you'll never see these types of voltages while playing music (unless you're near max volume with 0dBF material.)

squeak9798
11-01-2006, 10:27 PM
ooh, ooh, i want to score squeak points!

do you reset your gains at different volume levels?!

Ding Ding Ding.

Now, obviously, resetting your gain so that you reach full volume at a volume level of 10 rather than 35 is going to change how loud the music is for a given volume setting, and it will limit how much of the volume range you can use.

But to run the simple experiment of testing the "sound differences" at various preout voltages, you can reset the amplifier's gain to reach full power output at a lower volume setting and then at a higher....and listen to both at the same SPL levels.

You won't hear a difference between them.


If the preout voltage affected sound quality we would all be driving around with our volumes maxed out because the higher preout voltage would "sound better".

iceteebone
11-01-2006, 10:31 PM
Anyone with a single headunit can do the experiment themselves.

Anyone want to guess as to how one can run an experiment to compare differences in preout voltage with their headunit?

Time for Ghosthunters....so I'll let you all come up with the answer as to how this can be accomplished :)

**** i forgot ghosthunters was on :( by the previews from the last one it looked good :(

too bad this forum didn't have a multi-quote option ;)

squeak9798
11-01-2006, 10:58 PM
**** i forgot ghosthunters was on :( by the previews from the last one it looked good :(

No good evidence this go round.

Next week should be interesting though.....results from the latest Shining hotel investigation :naughty:

iceteebone
11-01-2006, 11:00 PM
No good evidence this go round.

Next week should be interesting though.....results from the latest Shining hotel investigation :naughty:

i liked the lighthouse in florida. that was spooky.

BlkonBlkFG
11-01-2006, 11:33 PM
WOW! Squeak is the man, hands down. :eek:

iceteebone
11-01-2006, 11:43 PM
WOW! Squeak is the man, hands down. :eek:

i've been saying the same thing is simpler terms :crap:

BlkonBlkFG
11-02-2006, 02:43 PM
I just meant how he came in here and quoted like 10 different people and corrected everything they said that was wrong. Thats all...

2kchevy06civic
11-02-2006, 02:47 PM
it's okay ice I still <3 you.

xploit2
11-02-2006, 04:42 PM
I just meant how he came in here and quoted like 10 different people and corrected everything they said that was wrong. Thats all...

well thats squeaks9798 opinion...It doesnt mean he is right...:p: we had like 5 people saying how better and different the sound was when they switched from 2V to 5V.
from my experience it does make a difference...otherwise why would eclipse or any other engineers bother in building headunits with 5V preouts??........

iceteebone
11-02-2006, 04:58 PM
well thats squeaks9798 opinion...It doesnt mean he is right...:p: we had like 5 people saying how better and different the sound was when they switched from 2V to 5V.
from my experience it does make a difference...otherwise why would eclipse or any other engineers bother in building headunits with 5V preouts??........

to sell them to noobs and the people who noticed differences, had way to many variables. ever hear of the scientific method? i suggest you look it up and then make comparisons ;)

BlkonBlkFG
11-02-2006, 05:03 PM
Maybe the difference in the HU wasnt b/c of the actual voltage of the preout, but maybe b/c of a different D/A processor rate or THD percentage or signal to noise ratio in addition to the solid signal of a higher voltage preout. EH?

xploit2
11-02-2006, 05:08 PM
to sell them to noobs and the people who noticed differences, had way to many variables. ever hear of the scientific method? i suggest you look it up and then make comparisons ;)

You make no sense Bro.

xploit2
11-02-2006, 05:09 PM
Maybe the difference in the HU wasnt b/c of the actual voltage of the preout, but maybe b/c of a different D/A processor rate or THD percentage or signal to noise ratio in addition to the solid signal of a higher voltage preout. EH?



Now thats more like it!! iceteebone learn something bro.

iceteebone
11-02-2006, 05:11 PM
You make no sense Bro.

when comparing 2 things, you can't use different cars and subwoofers and different brands of headunits with different processing. too many variables on why one sounded better then the other.

iceteebone
11-02-2006, 05:15 PM
use these ideals when making scientific comparisons and present the findings to us when you are done :)

http://en.wikipedia.org/wiki/Scientific_Method

squeak9798
11-02-2006, 06:01 PM
well thats squeaks9798 opinion...It doesnt mean he is right...:p:

Actually, there's no opinion about it. It's simply a fact that some people aren't aware of, and many attempt to draw valid conclusions from invalid comparisons


we had like 5 people saying how better and different the sound was when they switched from 2V to 5V.

And all of those people were comparing completely different headunits, likely with different settings and even in some instances in completely different vehicles. Which makes their opinions completely worthless as the "experiements" they conducted were completely invalid in every sense.


If you want to test it yourself, we explained how to do a simple experiment to show you what differences exist (or rather, what differences don't exist).

Flipx99
11-03-2006, 10:16 AM
I actually learned something. I thought if you kept the gains down (less than preout voltage) it would make the amp work less hard. I am still uncertain as to why, however.

It would look like the signal would be less amplified, thus making the amp work less. I guess that is why they say the gain is not a volume knob.

This leads to another question...does when you change the volume on the CD player itself, does the internal amp work less?

the727kid
11-05-2006, 09:51 AM
Ok I got my new CD5000 in. And here are my results: At first it is significantly louder, but once I got ahold of a DMM and set my gains according, it is about the same. One thing I did notice though are my speakers seem to be a tad bit louder, but I believe the settings on the HU are responsibile for that (there is so many **** options on this thing I'mma need to study the booklet, it's like a novel). But overall jumping from 2v to 8v was not much of a difference in sound level.

http://i74.photobucket.com/albums/i269/the727kid/Speakers009.jpg

BlkonBlkFG
11-05-2006, 11:30 AM
what about the quality of the sound? Did you have a 1-bit processor before or a 24-bit? If you went from 1 to 24 how much of a difference in sound was it? Was it worth the money to make the switch in your opinion?

iceteebone
11-05-2006, 11:33 AM
i've had 1 and 24 bit and haven't noticed a difference

squeak9798
11-05-2006, 11:52 AM
what about the quality of the sound? Did you have a 1-bit processor before or a 24-bit? If you went from 1 to 24 how much of a difference in sound was it? Was it worth the money to make the switch in your opinion?

There is much more to a headunit than the "bits" of the DAC.

BlkonBlkFG
11-05-2006, 12:43 PM
OK cool...i'm totally new to these technical specs. Can you please explain.

msimon
11-05-2006, 04:23 PM
For all of you wondering if lower preout voltage makes an amplifier "work harder", check out werewolf's reply in the following thread, http://www.audiogroupforum.com/csforum/showthread.php?t=2948&highlight=gain

BlkonBlkFG
11-05-2006, 08:43 PM
Great Find! Thanks man..makes things so clear now.

vpkb1998
11-08-2006, 09:06 AM
so, the benefit of the higher voltage is less chance of having noise?

BlkonBlkFG
11-08-2006, 08:14 PM
correct...the higher the voltage and lower impedence the less noise that will come out of the headunit. Then that signal that is sent and amplified will come out better b/c its amplifying a clean signal instead of amplifying a bad one.

iceteebone
11-08-2006, 08:47 PM
correct...the higher the voltage and lower impedence the less noise that will come out of the headunit. Then that signal that is sent and amplified will come out better b/c its amplifying a clean signal instead of amplifying a bad one.

no, higher voltage simply means, IF you have noise in your system, there would be less of a chance of hearing it since you won't be amplifying it as much. there shouldn't be noise no matter what impedence or voltage you run