RCA Output voltage

[Deez Nutz]

I was curious to know does it matter the amount of voltage a hu put out
to the rca jacks? I have a Boss hu and it says it has 5 volt pre amp
outs. I am fixing to get a new car in which I will be purchasing a new
hu, and I wanted to find out if the voltage output was something to
weigh into the decision. Thanks in advance for any and all suggestions.

[MOSFET]

A couple of things. First, when a HU says 4 or 5 volt pre-amp (RCA) output,
that is a maximum number. Nominally, your HU typically puts out a much
lower voltage. Also, pretty much EVERY HU made today puts out AT LEAST 2 or
more volts which, 15 years ago, was considered high voltage. So there
really isn't much difference between the high voltage and low-voltage
outputs.

Second, I have owned a high voltage (4 volts) HU (an Alpine 7939) and
several non high voltage HU's (2-3 volts) including my current HU, an Alpine
9853, and I don't notice any difference in sound quality. I think this
whole voltage thing has more to do with marketing than any meaningful sound
quality improvement. As I frequently point out, if 4-5 voltage pre-amp
outputs were the end-all-be-all, why don't multi-kilobuck high-end home
equipment (Mark Levinson, Krell, Conrad Johnson, etc.) use them? The
answer is that THEY DON'T help sound quality wise.

What they CAN do, however, is sometimes cover up induced noise problems
(like alternator whine caused by ground loops) by allowing you to turn the
gains on your amp lower. However, I see this as a band-aid. A 5 volt
pre-amp output may allow you to REDUCE noise problems, but it can never
ELIMINATE them. A good installation with proper grounding on all components
CAN ALWAYS (at least in my experience) eliminate ground-loops. And other
types of induced noise can be dealt with as well. To me, it makes more
sense to deal with the problem, rather than trying to cover it up.

So for that and other reasons, I don't see much benefit in high voltage
outputs (of course, I don't think a high voltage output HURTS anything). I
just wouldn't make that a very high priority in selecting a HU.

My $.02,

MOSFET

"Deez Nutz" > wrote in message
oups.com...
> I was curious to know does it matter the amount of voltage a hu put out
> to the rca jacks? I have a Boss hu and it says it has 5 volt pre amp
> outs. I am fixing to get a new car in which I will be purchasing a new
> hu, and I wanted to find out if the voltage output was something to
> weigh into the decision. Thanks in advance for any and all suggestions.
>

[Matt Ion]

High-voltage outputs theoretically *allow for* greater dynamic range, better
noise *immunity* (not just covering it up), and overall better S/N. To see any
REAL benefit from it, however, your next downstream component (amp, crossover,
whatever) needs to be able to accept the greater input. If your amp's input
clips any anything over, say, 2V, you won't be able to crank the deck's output
any more than you would a standard deck, and you won't see any significant
difference.

As an example, if your system has a noise floor of 0.05V (I'm just pulling
numbers out of my ass here for the sake of illustration, BTW - these things are
normally measured in dBu, dBV, or other similar scales, rather than in absolute
voltages), and your deck has a max output of 1V (actually, I think 1.8V is most
common, but I'll use 1V for easier reference), the noise will be a lot more
noticeable than if your deck can push signal at 5V, and thus much higher above
the noise floor. (Just a quick calculation in my head, I believe the 1V example
would be only a 13dB S/N ratio; the 5V example would allow up to 20dB...
assuming, again, that the amp or crossover's input can accept that level).

This actually is not a new concept... pro audio gear has for decades
traditionally used +4dBm as a "standard" signal level, while consumer (home)
audio equipment uses -10dBm. Connecting, say, a home tape deck's output to a
pro mixer's input requires a lot of input gain, and with it increased chance of
noise, while feeding a pro mixer's output to a home tape deck requires careful
control of the output gains to avoid clipping the deck's inputs. Pro gear, of
course, uses the "hotter" signal for exactly the same reason: better dynamic
range, better noise rejection, better S/N ratio.


MOSFET wrote:
> A couple of things. First, when a HU says 4 or 5 volt pre-amp (RCA) output,
> that is a maximum number. Nominally, your HU typically puts out a much
> lower voltage. Also, pretty much EVERY HU made today puts out AT LEAST 2 or
> more volts which, 15 years ago, was considered high voltage. So there
> really isn't much difference between the high voltage and low-voltage
> outputs.
>
> Second, I have owned a high voltage (4 volts) HU (an Alpine 7939) and
> several non high voltage HU's (2-3 volts) including my current HU, an Alpine
> 9853, and I don't notice any difference in sound quality. I think this
> whole voltage thing has more to do with marketing than any meaningful sound
> quality improvement. As I frequently point out, if 4-5 voltage pre-amp
> outputs were the end-all-be-all, why don't multi-kilobuck high-end home
> equipment (Mark Levinson, Krell, Conrad Johnson, etc.) use them? The
> answer is that THEY DON'T help sound quality wise.
>
> What they CAN do, however, is sometimes cover up induced noise problems
> (like alternator whine caused by ground loops) by allowing you to turn the
> gains on your amp lower. However, I see this as a band-aid. A 5 volt
> pre-amp output may allow you to REDUCE noise problems, but it can never
> ELIMINATE them. A good installation with proper grounding on all components
> CAN ALWAYS (at least in my experience) eliminate ground-loops. And other
> types of induced noise can be dealt with as well. To me, it makes more
> sense to deal with the problem, rather than trying to cover it up.
>
> So for that and other reasons, I don't see much benefit in high voltage
> outputs (of course, I don't think a high voltage output HURTS anything). I
> just wouldn't make that a very high priority in selecting a HU.
>
> My $.02,
>
> MOSFET
>
> "Deez Nutz" > wrote in message
> oups.com...
>
>>I was curious to know does it matter the amount of voltage a hu put out
>>to the rca jacks? I have a Boss hu and it says it has 5 volt pre amp
>>outs. I am fixing to get a new car in which I will be purchasing a new
>>hu, and I wanted to find out if the voltage output was something to
>>weigh into the decision. Thanks in advance for any and all suggestions.
>>
>
>
>

[bob wald]

i havent read all the dribble others have wrote but i know
this........(((5v is very very good))) cause alot of amps wont take
more than that but they could start making amps to take more volts from
outputs.
i have 2 jensen cd players with 5v outs...i love them more than any
other piece of car audio i ever owned..
the sound is increditable.
yes it makes a giant difference...
never go under 5v outs...

[bob wald]

also you look at high priced recievers theyll have 5v outs......

[bob wald]

heres 1 of my secrets. go look at a $500+ reciever n try to find 1 like
its specs for less.

[MOSFET]

Pro gear, of
> course, uses the "hotter" signal for exactly the same reason: better
dynamic
> range, better noise rejection, better S/N ratio.
>
Pro gear typically uses balanced signals, unlike home and car pre-amp
outputs, which COMPLETELY irradiates extraneous noise (which is necessary in
a pro environment where you typically have VERY long pre-amp runs AND all
sorts of electromagnetic interference).

MOSFET

[MOSFET]

better
> noise *immunity* (not just covering it up),

How is better noise immunity NOT covering noise up? THINK about it. It's
the same thing, Matt, just another way of looking at it.

I mean, you either have a noise problem or you don't, right? So IF YOU DO,
and your "noise immunity" (as you call it) comes into play, explain to me
how that is not just another way of saying covering up the noise.

Sometimes I get the feeling your turning into Captain Matt.

MOSFET

[MOSFET]

And one more thing, while we're on the subject, Matt....

How about answering the OP's question? I mean, your post was VERY
impressive sounding and all (even though it made about as much sense to me
as one of Bob's rants). But I reread it and noticed you didn't answer the
question.

QUESTION:
Deez wants to know will a high voltage HU make an audible difference:

ANSWER:
Brandonb: Nope
Me: Tried both kind, didn't hear a difference.

You: Theoretically blah blah noise floor at -10dBm vs. +4dBm dBu, dBV, DVD,
VCR, ESPN blah blah blah....

Will Deez hear a difference, Matt? Yes or no?

MOSFET

[Matt Ion]

MOSFET wrote:
> Pro gear, of
>
>>course, uses the "hotter" signal for exactly the same reason: better
>
> dynamic
>
>>range, better noise rejection, better S/N ratio.
>>
>
> Pro gear typically uses balanced signals, unlike home and car pre-amp
> outputs, which COMPLETELY irradiates extraneous noise (which is necessary in
> a pro environment where you typically have VERY long pre-amp runs AND all
> sorts of electromagnetic interference).

"Irradiates"? Heheheh... only in a nuclear-powered system :)

Not all pro components have balanced I/O... most, but not all.

Balanced I/O reduces and ALMOST completely erradicates (I think that's the word
you were after) noise *induced in the wiring* (not completely, and not in all
instances - check out various stories around the 'net of church sound systems
pickup up truckers' CBs!) but have no effect on various noise floors inherent in
all electronic gear.

[Matt Ion]

MOSFET wrote:
> And one more thing, while we're on the subject, Matt....
>
> How about answering the OP's question? I mean, your post was VERY
> impressive sounding and all (even though it made about as much sense to me
> as one of Bob's rants). But I reread it and noticed you didn't answer the
> question.
>
> QUESTION:
> Deez wants to know will a high voltage HU make an audible difference:
>
> ANSWER:
> Brandonb: Nope
> Me: Tried both kind, didn't hear a difference.
>
> You: Theoretically blah blah noise floor at -10dBm vs. +4dBm dBu, dBV, DVD,
> VCR, ESPN blah blah blah....
>
> Will Deez hear a difference, Matt? Yes or no?

Now I'm starting to wonder if Howdy has jacked your account, or if you're just
being intentionally obstinate? Got a touch of the PMS?

I answered his question in my post: it CAN make a difference IF he uses other
downstream equipment (crossover or amp) that can accept the hotter signal. I
answered that RIGHT AT THE TOP and then went on to explain WHY that is.

Whether Deez will actually hear a difference, nobody here can say. I don't know
what the rest of the his system is like, if he has shyte speakers, or if he's
tone-deaf. He might drop tens of thousands into a system and not be able to
hear the difference between that an a stock AM radio.

[MOSFET]

No, it irradiates the noise so it can't be handled for several thousand
years. That get's rid of it!!! ;)

MOSFET

"Matt Ion" > wrote in message
news:73FJg.489044$iF6.65770@pd7tw2no...
> MOSFET wrote:
> > Pro gear, of
> >
> >>course, uses the "hotter" signal for exactly the same reason: better
> >
> > dynamic
> >
> >>range, better noise rejection, better S/N ratio.
> >>
> >
> > Pro gear typically uses balanced signals, unlike home and car pre-amp
> > outputs, which COMPLETELY irradiates extraneous noise (which is
necessary in
> > a pro environment where you typically have VERY long pre-amp runs AND
all
> > sorts of electromagnetic interference).
>
> "Irradiates"? Heheheh... only in a nuclear-powered system :)
>
> Not all pro components have balanced I/O... most, but not all.
>
> Balanced I/O reduces and ALMOST completely erradicates (I think that's the
word
> you were after) noise *induced in the wiring* (not completely, and not in
all
> instances - check out various stories around the 'net of church sound
systems
> pickup up truckers' CBs!) but have no effect on various noise floors
inherent in
> all electronic gear.

[MOSFET]

So your answer is "it might, or it might not but I'm going to pick apart
everything MOSFET said instead of giving you a straight answer".

OK, fine, Matt.

You are TRULY effecting my enjoyment of this newsgroup and I'm considering
putting you on my blocked list (though most of your posts are intelligent
and insightful so I don't want to).

But listen to me, PLEASE. Why don't you put me on your blocked list. I'm
dead serious. Obviously there's something that bugs you about my posts
because you nitpick nearly every one. PLEASE PUT ME ON YOUR BLOCKED LIST!

Thank you,

Nick

MOSFET

"Matt Ion" > wrote in message
news:O7FJg.489050$iF6.415856@pd7tw2no...
> MOSFET wrote:
> > And one more thing, while we're on the subject, Matt....
> >
> > How about answering the OP's question? I mean, your post was VERY
> > impressive sounding and all (even though it made about as much sense to
me
> > as one of Bob's rants). But I reread it and noticed you didn't answer
the
> > question.
> >
> > QUESTION:
> > Deez wants to know will a high voltage HU make an audible difference:
> >
> > ANSWER:
> > Brandonb: Nope
> > Me: Tried both kind, didn't hear a difference.
> >
> > You: Theoretically blah blah noise floor at -10dBm vs. +4dBm dBu, dBV,
DVD,
> > VCR, ESPN blah blah blah....
> >
> > Will Deez hear a difference, Matt? Yes or no?
>
> Now I'm starting to wonder if Howdy has jacked your account, or if you're
just
> being intentionally obstinate? Got a touch of the PMS?
>
> I answered his question in my post: it CAN make a difference IF he uses
other
> downstream equipment (crossover or amp) that can accept the hotter signal.
I
> answered that RIGHT AT THE TOP and then went on to explain WHY that is.
>
> Whether Deez will actually hear a difference, nobody here can say. I
don't know
> what the rest of the his system is like, if he has shyte speakers, or if
he's
> tone-deaf. He might drop tens of thousands into a system and not be able
to
> hear the difference between that an a stock AM radio.
>

[MOSFET]

You really should reread that post of yours and ask yourself "do I REALLY
expect the OP to understand all of this?" because you don't explain ANY of
the terms you use. If you look at my posts, you will notice that I explain
terms like signal to noise ratios and dynamic range and so on (in fact, I
pretty much explain EVERY acronym I ever use).

Be honest with yourself, Matt. Did you REALLY intend the OP to learn from
what you wrote, or was this an attempt for you to use a lot of terms YOU
KNEW most people would not understand in an attempt to sound superior and
smarter (smarter than ME in particular). BE HONEST.

Again, reread that post of yours. THINK about the original poster (who he
is, how old he might be, etc.). Remember what we are here for, to HELP
people. If that is your goal (as it is mine), you are tripping over your
ego.

Nick

"Matt Ion" > wrote in message
news:O7FJg.489050$iF6.415856@pd7tw2no...
> MOSFET wrote:
> > And one more thing, while we're on the subject, Matt....
> >
> > How about answering the OP's question? I mean, your post was VERY
> > impressive sounding and all (even though it made about as much sense to
me
> > as one of Bob's rants). But I reread it and noticed you didn't answer
the
> > question.
> >
> > QUESTION:
> > Deez wants to know will a high voltage HU make an audible difference:
> >
> > ANSWER:
> > Brandonb: Nope
> > Me: Tried both kind, didn't hear a difference.
> >
> > You: Theoretically blah blah noise floor at -10dBm vs. +4dBm dBu, dBV,
DVD,
> > VCR, ESPN blah blah blah....
> >
> > Will Deez hear a difference, Matt? Yes or no?
>
> Now I'm starting to wonder if Howdy has jacked your account, or if you're
just
> being intentionally obstinate? Got a touch of the PMS?
>
> I answered his question in my post: it CAN make a difference IF he uses
other
> downstream equipment (crossover or amp) that can accept the hotter signal.
I
> answered that RIGHT AT THE TOP and then went on to explain WHY that is.
>
> Whether Deez will actually hear a difference, nobody here can say. I
don't know
> what the rest of the his system is like, if he has shyte speakers, or if
he's
> tone-deaf. He might drop tens of thousands into a system and not be able
to
> hear the difference between that an a stock AM radio.
>

[Matt Ion]

MOSFET wrote:
> So your answer is "it might, or it might not but I'm going to pick apart
> everything MOSFET said instead of giving you a straight answer".

Okay, so how AM I supposed to give a straight answer as to whether or not
someone else will hear a difference in his system? If I say "yes he will" and
he's tone deaf, then he'll come back saying I'm a liar... if I say "no he won't"
then he may go and upgrade anyway, find out he does hear a difference, and say
I'm a liar. The only straight answer I, you, or anyone else can give to that
question is, "he might."

> You are TRULY effecting my enjoyment of this newsgroup and I'm considering
> putting you on my blocked list (though most of your posts are intelligent
> and insightful so I don't want to).

Go ahead, I'll try not to lose any sleep over it.

> But listen to me, PLEASE. Why don't you put me on your blocked list. I'm
> dead serious. Obviously there's something that bugs you about my posts
> because you nitpick nearly every one. PLEASE PUT ME ON YOUR BLOCKED LIST!

How is adding more detail and expanding on things "nitpicking"?

[Matt Ion]

MOSFET wrote:
> You really should reread that post of yours and ask yourself "do I REALLY
> expect the OP to understand all of this?"

Just as I can't know how good his hearing is, I don't know what his level of
education or understanding is. So I explain things the best *I* can; I'm not an
instructor. If he or someone else gains some useful knowledge from it, then
good. If not, I'm only wasting my own time.

> Again, reread that post of yours. THINK about the original poster (who he
> is, how old he might be, etc.). Remember what we are here for, to HELP
> people. If that is your goal (as it is mine), you are tripping over your
> ego.

Whatever. Just **** off and block me, and we'll both be happier.

[MOSFET]

> Just **** off

Well, OK, Matt. Thank you for taking the time to respond to my concerns
regarding this OBVIOUS tension between us (nitpicking nearly every one of my
posts).

As always, your responses are intelligent and thoughtful.

MOSFET

[MOSFET]

> How is adding more detail and expanding on things "nitpicking"?

I already gave you an example at the beginning of this thread: "Noise
immunity" vs. "covering up".

Frankly, "covering up" is a much better term because "immunity" implies
eradication of noise. Like if you are given a vaccine against a particular
disease, you are immune to it's effects. If you are exposed to the disease
(in this case "noise"), an immunity would imply it would have absolutely no
effect on you (like immunization against small pox implies if you are
exposed to the smallpox virus, it will have absolutely no effect). This IS
NOT a good analogy to what we are talking about with noise. If you have a
sever ground-loop problem, a high-voltage pre-amp does not give you
"immunity" against ground loop noise.

Covering-up is a MUCH BETTER analogy (though perhaps not perfect) than
"immunity".

THIS MATT, IS THE KIND OF NITPICKING I'M TALKING ABOUT. BLOCK ME OR LEAVE
MY POSTS ALONE (unless, of course, I get something horribly wrong like your
advice about there being no such thing as a pre-amp for an iRiver you gave
that guy).

Thank you,

Nick

[Matt Ion]

MOSFET wrote:

> THIS MATT, IS THE KIND OF NITPICKING I'M TALKING ABOUT.

You're the one who's nit-picking now...

> BLOCK ME OR LEAVE MY POSTS ALONE

My, don't you think highly of yourself. I'm not here to nit-pick your posts. I'm
here to offer advice to ANYONE who asks, and to engage in semi-intelligent
discussions relating to car audio. If that means correcting, adding to,
expanding on, agreeing with, on ****ting on your posts, I'll do so. If that
means correcting, adding to, expanding on, agreeing with, or ****ting on ANYONE
ELSE'S posts, I'll do so.

Don't take everything so personally, it's NOT all about Nick.

My posts obviously upset you, so tell ya what, YOU block ME, and you'll have a
happier life.

[MOSFET]

> Don't take everything so personally, it's NOT all about Nick.
>

Good point. You do this annoying nitpicking thing to everyone.

Again, before you start typing, ask yourself these questions: "Is this
relevant to the OP's question? Is this REALLY going to help him? Does this
FUNDAMENTALLY change the advice I am critiquing (if you are critiquing
someone else's advice)? Or is this just a way to prove how smart I am?".

You see, Matt, I have noticed that when it comes to some (not all, of
course) of your posts, the answer to these questions is "no".

Because you're right, you do this to a lot of people and I imagine it's
annoying to them as well.

Nick

[Matt Ion]

MOSFET wrote:
>>Don't take everything so personally, it's NOT all about Nick.
>>
>
>
> Good point. You do this annoying nitpicking thing to everyone.
>
> Again, before you start typing, ask yourself these questions: "Is this
> relevant to the OP's question? Is this REALLY going to help him? Does this
> FUNDAMENTALLY change the advice I am critiquing (if you are critiquing
> someone else's advice)?"

Kinda depends on the OP. You assume everyone you respond to is a brain-dead
moron and deserves a simple one-dimensional response. I assume they might have
a hlaf a clue to start with, and learning a little more about how things work
might actually help them in the future. I also try to remember that OTHER
people besides to OP will be reading the thread, and that someone else might
also be able to benefit from a little more knowledge.

[almond]

gee it's just like roe all over again, which is why i left.
really where you see the pre-out voltage at work is in the amps gains.
say you have a deck at 2v you would set the gain maybe 2/3 of they way
up (with a dmm of course) and with and 8v deck (like my eclipse) you
would have to turn the gain up say 1/3 of the way. this keeps your amp
from working as hard. i've used decks with 8v preouts all the way down
to a 1 volt preout and can tell you there is a huge difference in the
gain setting and sq. just my 2 cents and really noone even needs to
listen to that but there it is.


--
almond

[Matt Ion]

almond wrote:

> really where you see the pre-out voltage at work is in the amps gains.
> say you have a deck at 2v you would set the gain maybe 2/3 of they way
> up (with a dmm of course) and with and 8v deck (like my eclipse) you
> would have to turn the gain up say 1/3 of the way. this keeps your amp
> from working as hard.

Well, this'll drive Nick crazy, but it's nitpick time again:

The output voltage of your deck in this instance make no difference whatsoever
to "how hard the amp works". Your deck is pushing out higher voltage, and your
gain control is dialing it back down. In the end, it makes no difference to the
amp.

For easy calculation, let's assume your deck puts out 2V and you run the gain at
full. The preamp section of the amp is getting up to a full 2V (fluctuating
with the signal, of course). Now you use a deck that outputs 6V. In order to
get the same output level, you have to turn the gain down to 1/3 (this is also
assuming a linear input, for the sake of easy calculation). So now you're back
down to a 2V signal coming out of the gain controls.

> i've used decks with 8v preouts all the way down
> to a 1 volt preout and can tell you there is a huge difference in the
> gain setting and sq. just my 2 cents and really noone even needs to
> listen to that but there it is.

There's going to be a difference in the gain controls, for sure, but differences
in sound quality are more likely due to many other factors besides just output
voltage. Any deck that outputs 8V is NOT going to be a "cheap" deck, to begin
with, and will inherently sound better than some electronics-superstore brand
deck with 1V output.

[MOSFET]

> Well, this'll drive Nick crazy, but it's nitpick time again:
>
> The output voltage of your deck in this instance make no difference
whatsoever
> to "how hard the amp works".

Good point.

And no, I don't consider this nitpicking at all........because it wasn't my
post (JUST KIDDING). ;)

That was an important clarification: Pre-amp voltage makes no difference
regarding how hard your amp works.

MOSFET

[almond]

yeah that sounds right now that i think of it. if your amp out put
voltage is 50v it's doesn't matter really what the input voltage is
your just going to set the gain to 50v.


--
almond

[bob wald]

i told you all yes..it make a difference.. but 5v is all ill try on most
amps made in the past....8v?
good luck with that...lol
can you kids understand????
2v-3v. laughssssss

[almond]

i'm running a niche audio na6000d it'll run at 8 volts in.


--
almond

[bob wald]

well almond ok just so you know. i got afew amps from yrs past.that cant
take above 5v.

[almond]

i realize that, and yeah if your amp can't handle an 8 volt input then
it's useless to have it.


--
almond