PDA

View Full Version : Does pre-out voltage make a huge difference?



Intercooler
03-03-2006, 11:54 PM
I was talking to a guyat the audio shop that does SPL competitions and has a few trophies to his credit and he said the pre-out voltage on a head unit makes a HUGE difference in overall power. He talked about it like it was steroids or something :D Is this a true statement? I am still learning so I just take it all in and be quite. What head unit holds the title for most pre-out? What Pioneer and Kenwood units has the most pre-outs?

BTW... He said Kenwood HU's are the best for SPL :eyebrow:

alphakenny1
03-03-2006, 11:58 PM
no, it doesn't SQ wise. in a nutshell higher the preout voltage the less your amp has to work (ie lower gain) and hence reduces noise.

azbass
03-04-2006, 12:00 AM
you will have higher head room.

Intercooler
03-04-2006, 12:24 AM
So you can go louder then.



They also talked a decent amount about the Eclipse line and I think on of those had the highest pre-out from what I overheard. I don't know much about Eclipse but are they good?

double_a
03-04-2006, 12:27 AM
Eclipse are GREAT hu's and their higher modles have 8v pre-outs.

alphakenny1
03-04-2006, 12:28 AM
no, you can't get louder because on a 8v preout HU, if you barely turn up the gain and immediately you might send a clipped signal. thats what happened when i was setting the gains on my sub amp, my HU clipped at 77/80, went to amp to turn up the gain, it almost clipped as i just turned the gain knob. it just enables your amp to not work as hard.

and yes eclipse basically has the highest preouts, 8v. Eclipse are awesome HUs.

Intercooler
03-04-2006, 12:45 AM
This guy had a Kenwood with 5V's. I think my Pioneer is only 2V so am I leaving something on the table by not have 5V + or is it something I won't really see or hear?

flakko
03-04-2006, 12:48 AM
goin from 4v (panasonic) to 5v (kenwood) i heard a HUGE difference.... had to turn my gains down a lot after hookin up the new HU.

Jdizzle
03-04-2006, 12:48 AM
i hate having 2v preamps..because i have to turn it up to like 40/63 to just hear sumthing

Intercooler
03-04-2006, 12:50 AM
I wish I would have found this site before I started. Oh well... now I can change it as I go.

rocky 59
03-04-2006, 12:52 AM
i had 2v preouts but then i got an EQ that up them to 7v i liked it. btw the Eq is for sale :D

alphakenny1
03-04-2006, 12:55 AM
its a nice thing to have BUT shouldn't be the sole reason why you buy an HU. its just a nice thing to have thats all.

iceteebone
03-04-2006, 12:57 AM
what happened to proper gain setting? preout voltage isn't a big deal

iceteebone
03-04-2006, 01:04 AM
also during normal listening, you'll never get the advertised preout voltage anyways

PepsiFiend69
03-04-2006, 07:28 PM
i had 2v preouts but then i got an EQ that up them to 7v i liked it. btw the Eq is for sale :D

ygpm


sorry for the thread jack :blush:

squeak9798
03-04-2006, 07:33 PM
Preamp output voltage does not make an audible difference.

The only, and I do mean ONLY, potential audible difference is that a higher preamp voltage allows a lower gain setting, which increases the signal-to-noise ratio and possibly decreases audible noise. BUT, if you have no noise with a lower output voltage, you will not hear a difference.

http://www.caraudio.com/forum/showthread.php?t=141851&highlight=voltage

Eldorado
03-04-2006, 07:36 PM
Sometimes is can be bad.
Some amps dont like a high imput voltage.

Prowler573
03-04-2006, 07:36 PM
also during normal listening, you'll never get the advertised preout voltage anyways

Ding! Ding! Ding! We haaaaave a winner! With a few notable exceptions even HUs advertised to have high(er than average) preamp output volages without the volume cranked on some pretty loud source material you'll not ever realize those levels of output from the preamp outs. Period.

(*says the admitted eXcelon fanboi*)
Even though I noticed a considerable difference going from a deck with (max of) 2v preamp outputs to one with a (max of) 5v preamp outputs I'm still not getting that 5 volts except on the odd occasion.

Eldorado
03-04-2006, 07:39 PM
My h/u has an under-rated preout voltage which kinda scares me.

m48xhp
03-04-2006, 07:57 PM
one thing that concerns me about my preouts is that they could be too high for the amp. mine are 6.5V (or as high as) and i have to keep my gains on my RF amp all the way down. it cant go any lower, but maybe it should.

Eldorado
03-04-2006, 08:00 PM
I have that concern as well
my pioneer does 6.5V and i was going to use an old school autotek thats definetly not rated for that high of an imput.
So im getting some new us amps amps, hopefully they will take the imput voltage

squeak9798
03-04-2006, 08:35 PM
one thing that concerns me about my preouts is that they could be too high for the amp. mine are 6.5V (or as high as) and i have to keep my gains on my RF amp all the way down. it cant go any lower, but maybe it should.

Not a problem.

Refer to the earlier discussion about how little output voltage there will be with music at listening levels.

Just as an example; I had an 8V preamp output (Eclipse 8053) connected to amplifiers that had a maximum input sensitivity of 1500mV (1.5V).....and I never had a problem.

With music, at listening level, that Pioneer is probably only putting out ~1V if you are lucky.

phantom240
03-04-2006, 09:12 PM
how about an alpine HU that is supposed to put out 4v. Something like 1.5v at normal volumes? if im lucky?

Prowler573
03-04-2006, 09:13 PM
how about an alpine HU that is supposed to put out 4v. Something like 1.5v at normal volumes? if im lucky?ikely less than half of your assumption.....

With music it would be under a volt at normal volumes....

Eldorado
03-04-2006, 09:42 PM
But all i listen to are tones :crazy:

FoxPro5
03-04-2006, 09:58 PM
It does make a difference, but not to the degree that you should sell your lower voltage deck for a higher one....unless you need better features in a new unit. An interesting read here on some high-end decks with different preamp voltages: http://www.nearfieldaudio.co.uk/forum/viewtopic.php?t=125&postdays=0&postorder=asc&&start=20

iceteebone
03-04-2006, 10:03 PM
Ding! Ding! Ding! We haaaaave a winner! With a few notable exceptions even HUs advertised to have high(er than average) preamp output volages without the volume cranked on some pretty loud source material you'll not ever realize those levels of output from the preamp outs. Period.

(*says the admitted eXcelon fanboi*)
Even though I noticed a considerable difference going from a deck with (max of) 2v preamp outputs to one with a (max of) 5v preamp outputs I'm still not getting that 5 volts except on the odd occasion.


what do i win :woot:

how many times has preout voltage been discussed lately?

blue
03-04-2006, 10:46 PM
It does make a difference, but not to the degree that you should sell your lower voltage deck for a higher one....unless you need better features in a new unit. An interesting read here on some high-end decks with different preamp voltages: http://www.nearfieldaudio.co.uk/forum/viewtopic.php?t=125&postdays=0&postorder=asc&&start=20
Hmmm .... I read the WHOLE thing , and found it very interesting.
Here's what I took away from it :

HU's do NOT all sound the same ( something I already knew ;) )
The DRZ9255 pretty much just KICKED ***
And lastly , I made the correct choice :up2somet:

Intercooler
03-04-2006, 10:50 PM
Preamp output voltage does not make an audible difference.

The only, and I do mean ONLY, potential audible difference is that a higher preamp voltage allows a lower gain setting, which increases the signal-to-noise ratio and possibly decreases audible noise. BUT, if you have no noise with a lower output voltage, you will not hear a difference.

http://www.caraudio.com/forum/showthread.php?t=141851&highlight=voltage



That as good reading. Everything you guys put up was good reading!


It looks like the higher voltage might be a good thing. I don't know if 8V is needed but 5V seems like a nice compromise. Maybe that is the reason the guys at my local audio shop like Kenwoods. I just bought another Honda to replace my 98 in the sig (new on is a 2001 EX) so I will probably be in the market for a new HU. I always wanted to try a Kenwood. Any suggestions on one? Has to be black to match the interior. :D

3.5Max6spd
03-04-2006, 11:13 PM
Truth is more than 4v preouts is overkill with 99% of the amps out there, and those that do accept higher voltage usually have an adjustable voltage input.

I've ran Eclipse's and its great to have those strong preouts and low output impedance. Is it better? Theoretically, yes. But its definitly not required . My system gets just as loud with my 4v outputs now and nothing has changed other than the HU swap, gains even remained the same. But that may have to do with the input sensitivity of my amps that allow me full output as low as 2.5v. So if you are somehow getting more headroom with a higher voltage hu then it could be credited to the design of the specifics amplifiers input stage. Some SPL amps are designed for burps and maximum output with a hotter signal.