OK, so my basic understanding is higher-voltage Preamps send better-quality
signal, generally speaking, correct?

If so, how does one go about attenuating the gain on any given amp in
relation to the preamp signal (nomatter which V it is)?

What tools does one need to do this?

....I don't even know if I'm phrasing my question correctly or not, but if
not, basically I want to know the proper techniques involved with setting
up an amp correctly - any given amp on any given head.

Thanks for your help fellas!

Matt

OK, so my basic understanding is higher-voltage Preamps send
better-quality
signal, generally speaking, correct?

No. They just output a higher voltage signal.

If so, how does one go about attenuating the gain on any given amp in
relation to the preamp signal (nomatter which V it is)?

Turn the knob.


What tools does one need to do this?

...I don't even know if I'm phrasing my question correctly or not, but if
not, basically I want to know the proper techniques involved with setting
up an amp correctly - any given amp on any given head.

http://www.installer.com/tech/gains.html

Matt Bhame wrote:

OK, so my basic understanding is higher-voltage Preamps send better-quality
signal, generally speaking, correct?

No not really... The reason it is LOW voltage on home systems is
so it is cleaner and then let the real power amp do the work...

In a car, the MARKETING HYPE makes folks think the higher voltage
is better, but its likely you will just turn that high voltage DOWN with
the amplifier gain control, so do you really need the high voltage in the
first place??

If so, how does one go about attenuating the gain on any given amp in
relation to the preamp signal (nomatter which V it is)?

See my paper on setting gains.
http://www.installer.com/tech/gains.html

its not too tough...

Eddie Runner

I find it somewhat ironic, and confusing, that in your article, you say,

"And by the same token a headunit with a LOW VOLT output might have to
be turned up all the way to 30 and might still not quite drive the
amplifier to full power... That sucks too!"

....which to me answers your own question of,

"...so do you really need the high voltage in the first place??"

__________________________________________________ ___________________


Aren't THD ratings exponential, as well? At RMS aren't their THD at
peak bottom compared the same amp running full tilt?

Therefore, if a low-voltage source has to be amplified to the max (and
isn't Gain merely an attenuation of potential amplification in a given
amplifier) and a high-voltage source at the same gain level severely
narrows the audible "swing", then wouldn't you rather one rather have a
high-voltage output, with a lower gain that achieves the identical swing
to a low-voltage, high-gain setup merely for the benefit of lowering the
amount of THD since you're never even creeping full-tilt on the amp?

Is *that* not the reason why high-voltage outputs are *preferred*?

__________________________________________________ ___________________


It is also my understanding that "voltage" in regards to PreOuts is
nearly identical to a Signal-to-Noise Ratio, versus how "voltage" is
used when an amplifier actually amplifies a signal. I thought PreAmp
Voltage was a rating against a common auto-amp noise floor, the higher
the voltage, the more signal being sent at the same noise floor - again,
like a S/N Ratio. If this is the case, then I don't see how a higher-V
preamp out would be any dirtier than a low-V preout.

What do you guys think?



Matt Bhame wrote:

OK, so my basic understanding is higher-voltage Preamps send
better-quality signal, generally speaking, correct?

No not really... The reason it is LOW voltage on home systems is
so it is cleaner and then let the real power amp do the work...

In a car, the MARKETING HYPE makes folks think the higher voltage
is better, but its likely you will just turn that high voltage DOWN
with the amplifier gain control, so do you really need the high
voltage in the first place??

If so, how does one go about attenuating the gain on any given amp in
relation to the preamp signal (nomatter which V it is)?

See my paper on setting gains.
http://www.installer.com/tech/gains.html

its not too tough...

Eddie Runner

I find it somewhat ironic, and confusing, that in your article, you say,

"And by the same token a headunit with a LOW VOLT output might have to
be turned up all the way to 30 and might still not quite drive the
amplifier to full power... That sucks too!"

...which to me answers your own question of,

"...so do you really need the high voltage in the first place??"

If the amplifier gain cannot be set to accomodate the input voltage, then
yes you'll run into a problem. This is very uncommon.


Aren't THD ratings exponential, as well? At RMS aren't their THD at
peak bottom compared the same amp running full tilt?

Nope. In fact, THD tends to be highest at low power levels. It only
increases dramatically once you've driven the amp into saturation. The
reason it's so high at lower power levels is twofold: 1) the "+N" component
dominates in that range; 2) crossover distortion and OPS asymmetries tend to
be more pronounced at lower volume levels. There may be other reasons for
it too, but I can't think of them off the top of my head.

Therefore, if a low-voltage source has to be amplified to the max (and
isn't Gain merely an attenuation of potential amplification in a given
amplifier)

The gain control does indeed tend to attenuate, though there are some
amplifiers where it actually amplifies. However, the amplification is
performed with simple op amp circuits which, in a properly constructed
circuit, effectively make this kind of amplification "perfect".

and a high-voltage source at the same gain level severely
narrows the audible "swing", then wouldn't you rather one rather have a
high-voltage output, with a lower gain that achieves the identical swing
to a low-voltage, high-gain setup merely for the benefit of lowering the
amount of THD since you're never even creeping full-tilt on the amp?

See my above remarks on THD.


Is *that* not the reason why high-voltage outputs are *preferred*?

I think they're preferred for the reason that there's a greater S/N due to a
presumed constant amount of inducted noise (eg. in the speaker wiring and
connections). However, this effect is minimal in the grand scheme of
things.


It is also my understanding that "voltage" in regards to PreOuts is
nearly identical to a Signal-to-Noise Ratio, versus how "voltage" is
used when an amplifier actually amplifies a signal. I thought PreAmp
Voltage was a rating against a common auto-amp noise floor, the higher
the voltage, the more signal being sent at the same noise floor - again,
like a S/N Ratio. If this is the case, then I don't see how a higher-V
preamp out would be any dirtier than a low-V preout.

What do you guys think?

It wouldn't be "dirtier". But it wouldn't be significantly "cleaner"
either. I'd look at the D/A conversion and frequency response of the head
before I'd look at the voltage. Oh, and by the way, I don't look at the D/A
conversion and frequency response either.

"Eddie Runner" wrote in message
...
Matt Bhame wrote:

OK, so my basic understanding is higher-voltage Preamps send
better-quality
signal, generally speaking, correct?

No not really... The reason it is LOW voltage on home systems is
so it is cleaner and then let the real power amp do the work...

In a car, the MARKETING HYPE makes folks think the higher voltage
is better, but its likely you will just turn that high voltage DOWN with
the amplifier gain control, so do you really need the high voltage in the
first place??

If so, how does one go about attenuating the gain on any given amp in
relation to the preamp signal (nomatter which V it is)?

See my paper on setting gains.
http://www.installer.com/tech/gains.html

its not too tough...

Eddie Runner

you do realize the noise floor in the home is many dBs less than in the car,
that's why you need more volts down the pipe.

If you have that noise problem then YES, but it is not
always a higher noise floor (in the RCA cables) than in
a home... I have seen some very quiet cars...

Eddie

Tha Ghee wrote:

you do realize the noise floor in the home is many dBs less than in the car,
that's why you need more volts down the pipe.

If you have that noise problem then YES, but it is not
always a higher noise floor (in the RCA cables) than in
a home... I have seen some very quiet cars...

And the noise floor is dominated by other factors anyway.

If you have that noise problem then YES, but it is not
always a higher noise floor (in the RCA cables) than in
a home... I have seen some very quiet cars...

And the noise floor is dominated by other factors anyway.




I've been told there are specific standards of "noise floors" for car audio
and home audio.

Horrible example, but I think this may demonstrate what I heard:

Every 100 dB S/N ratio compared to given noise floor is = to 1V.

Noise Floor is 5 parts for car, one part for home.

Therefore, to obtain a nice round S/N ratio like 100dB, you'd need 5V for
car but only 1V for home.

I am sure this is a highly-inaccurate analogy, but is this not
fundamentally correct (turning your cheek to my inaccuracies, etc.)?

I've been told there are specific standards of "noise floors" for car
audio
and home audio.

Horrible example, but I think this may demonstrate what I heard:

Every 100 dB S/N ratio compared to given noise floor is = to 1V.

Noise Floor is 5 parts for car, one part for home.

Therefore, to obtain a nice round S/N ratio like 100dB, you'd need 5V for
car but only 1V for home.

I am sure this is a highly-inaccurate analogy, but is this not
fundamentally correct (turning your cheek to my inaccuracies, etc.)?

It's in accurate in that it's not nearly as universal as your example seems
to suggest. But more importantly, the noise floor in a properly installed
audio system (that is, no ground loops, no faulty equipment, good electrical
system) is negligible anyway.

yes, the noise floor in a car listening area is dominated by
wind noises, tire noises engine noises, and the yacky folks
in the backseat... The high voltage pre amp signal wont
help that noise floor at all.....

Mark Zarella wrote:

If you have that noise problem then YES, but it is not
always a higher noise floor (in the RCA cables) than in
a home... I have seen some very quiet cars...

And the noise floor is dominated by other factors anyway.

"Eddie Runner" wrote in message
...
If you have that noise problem then YES, but it is not
always a higher noise floor (in the RCA cables) than in
a home... I have seen some very quiet cars...

Eddie

Tha Ghee wrote:

you do realize the noise floor in the home is many dBs less than in the
car,
that's why you need more volts down the pipe.

yes but on average, (that what manufactures make money on) are louder than
home setups, you also have more EMI/RFI so you need the higher volts.

"Eddie Runner" wrote in message
...
yes, the noise floor in a car listening area is dominated by
wind noises, tire noises engine noises, and the yacky folks
in the backseat... The high voltage pre amp signal wont
help that noise floor at all.....

Mark Zarella wrote:

If you have that noise problem then YES, but it is not
always a higher noise floor (in the RCA cables) than in
a home... I have seen some very quiet cars...

And the noise floor is dominated by other factors anyway.

yes it will, that's why they have higher lineouts.

yes it will, that's why they have higher lineouts.

High voltage preouts make your tires quieter and reduce wind noise?

yes but on average, (that what manufactures make money on) are louder than
home setups, you also have more EMI/RFI so you need the higher volts.

Come on, people. Do you folks honestly believe you can hear the difference
in S/N between 100dB and 97dB? This newsgroup is just becoming insane in
recent weeks...

No, in my experience it is RARE to actually need the high volts...
Folks dont buy the high volts CAUSE THEY NEED IT!
They buy it cause it is in BIG PRINT in the adds and they
THINK IT IS A FEATURE!!

I have been installing professionally since 1974. About 79 or
80 we started to see RCA level car stereos and amps... They
were LOW volt (about 1.5 volts) and the HIGH VOLT radios
didnt start coming out till 4 or 5 years ago.... I got by just fine
for the YEARS and YEARS I installed without high volt radios!

Amps can usually be driven to full output power with about 1volt!
Any more than 1 volt and the amp gain will be be turned down to
change the HIGH VOLT radio to the 1volt the amp wants to see.
high volt or low volt radios doesnt matter, the amp still sees about 1 volt
after the amp gain control...

If you did have noise problems you couldnt get rid of, the high volt
radios would let you turn the high volts down and also turn the noise
problem down as well.... But installers dont like to be told they
CANT get rid of noises by themselves... ;-)

Eddie Runner

Tha Ghee wrote:

yes but on average, (that what manufactures make money on) are louder than
home setups, you also have more EMI/RFI so you need the higher volts.

that was my point Mark.
You should have explained it a little better like I did
he thought you were agreeing with him... ;-)

Mark Zarella wrote:

yes it will, that's why they have higher lineouts.

High voltage preouts make your tires quieter and reduce wind noise?

"Mark Zarella" wrote in message
...
yes it will, that's why they have higher lineouts.

High voltage preouts make your tires quieter and reduce wind noise?

no it will supply more downstream voltage, so you can turn your gains down
which will contribute to a better sounding system.

"Mark Zarella" wrote in message
...
yes but on average, (that what manufactures make money on) are louder
than
home setups, you also have more EMI/RFI so you need the higher volts.

Come on, people. Do you folks honestly believe you can hear the
difference
in S/N between 100dB and 97dB? This newsgroup is just becoming insane in
recent weeks...

what does this have to do with what I posted??

High voltage preouts make your tires quieter and reduce wind noise?

no it will supply more downstream voltage, so you can turn your gains down
which will contribute to a better sounding system.

How does reducing the gain contribute to a better sounding system?

Come on, people. Do you folks honestly believe you can hear the
difference
in S/N between 100dB and 97dB? This newsgroup is just becoming insane
in
recent weeks...

what does this have to do with what I posted??

The discussion has consisted of you and others being nitpicky about noise
levels, which are entirely dominated by power supply issues, grounding, and
road noise. Noise picked up in the RCAs along the way to the amplifier is
negligible. Therefore, high voltage preouts are useless.

Simply turning your gains down doesnt contribute to a better sounding system!
In fact, if anything attenuating the signal should (theoreticly) make it sound
worse!

Tha Ghee wrote:

no it will supply more downstream voltage, so you can turn your gains down
which will contribute to a better sounding system.

"Mark Zarella" wrote in message
...
High voltage preouts make your tires quieter and reduce wind noise?

no it will supply more downstream voltage, so you can turn your gains
down
which will contribute to a better sounding system.

How does reducing the gain contribute to a better sounding system?

I meant less noise in the system not better sounding sorry.

"Eddie Runner" wrote in message
...
Simply turning your gains down doesnt contribute to a better sounding
system!
In fact, if anything attenuating the signal should (theoreticly) make it
sound
worse!

Tha Ghee wrote:

no it will supply more downstream voltage, so you can turn your gains
down
which will contribute to a better sounding system.

less noise it what I meant.

"Mark Zarella" wrote in message
...
Come on, people. Do you folks honestly believe you can hear the
difference
in S/N between 100dB and 97dB? This newsgroup is just becoming insane
in
recent weeks...

what does this have to do with what I posted??

The discussion has consisted of you and others being nitpicky about noise
levels, which are entirely dominated by power supply issues, grounding,
and
road noise. Noise picked up in the RCAs along the way to the amplifier is
negligible. Therefore, high voltage preouts are useless.

not at all in a car they're very necessary noisy environment, little volts
DC, less than ideal wire runs, and many items that add EMI/RFI. I'm not
nitpicking just pointing things out.

How does reducing the gain contribute to a better sounding system?

I meant less noise in the system not better sounding sorry.

Ok, then how does reducing the gain lead to less noise?

The discussion has consisted of you and others being nitpicky about
noise
levels, which are entirely dominated by power supply issues, grounding,
and
road noise. Noise picked up in the RCAs along the way to the amplifier
is
negligible. Therefore, high voltage preouts are useless.

not at all in a car they're very necessary noisy environment, little volts
DC, less than ideal wire runs, and many items that add EMI/RFI. I'm not
nitpicking just pointing things out.

You just completely ignored what I said. You're talking about the RCA wires
picking up EMI/RFI. I'm telling you that that particular source of noise is
completely overwhelmed by road noise, "installation noise", and power supply
noise. Even if you were to be able to completely eliminate the noise picked
up in the wires, the overall noise floor would remain unchanged.

"Mark Zarella" wrote in message
...
How does reducing the gain contribute to a better sounding system?

I meant less noise in the system not better sounding sorry.

Ok, then how does reducing the gain lead to less noise?

no increasing the gains and large input voltage leads to less noise.

Ok, then how does reducing the gain lead to less noise?

no increasing the gains and large input voltage leads to less noise.

Your reasoning is circular. My first question to you was why does higher
voltage reduce wind and tire noise. Your reply was that it allowed you to
turn your gains down. Then I asked why turning your gains down reduced
noise. And you reply that the large input voltage leads to less noise.

So now that you've brought us back full circle, I still have no idea why the
concept of gain came into the conversation. So I'll ask again, because I'm
a masochist...how does increasing the voltage reduce wind and tire noise?

"Mark Zarella" wrote in message
...
Ok, then how does reducing the gain lead to less noise?

no increasing the gains and large input voltage leads to less noise.

Your reasoning is circular. My first question to you was why does higher
voltage reduce wind and tire noise. Your reply was that it allowed you to
turn your gains down. Then I asked why turning your gains down reduced
noise. And you reply that the large input voltage leads to less noise.

So now that you've brought us back full circle, I still have no idea why
the
concept of gain came into the conversation. So I'll ask again, because
I'm
a masochist...how does increasing the voltage reduce wind and tire noise?

I never said it reduces wind & tire noise just background and EMI/RFI, the
wind & tire noise is handled by SD.

Your reasoning is circular. My first question to you was why does
higher
voltage reduce wind and tire noise. Your reply was that it allowed you
to
turn your gains down. Then I asked why turning your gains down reduced
noise. And you reply that the large input voltage leads to less noise.

So now that you've brought us back full circle, I still have no idea why
the
concept of gain came into the conversation. So I'll ask again, because
I'm
a masochist...how does increasing the voltage reduce wind and tire
noise?

I never said it reduces wind & tire noise just background and EMI/RFI, the
wind & tire noise is handled by SD.

But the noise that you're referring to is miniscule compared to the other
more prominent sources of noises. In other words, it makes absolutely no
difference because the noise floor is determined by road noise and grounds
more than anything else.

I don't think Tha Ghee is keeping up I think he's looking thru purple
tinted glasses.



In article , "Mark Zarella"
wrote:
The discussion has consisted of you and others being nitpicky about
noise
levels, which are entirely dominated by power supply issues, grounding,
and
road noise. Noise picked up in the RCAs along the way to the amplifier
is
negligible. Therefore, high voltage preouts are useless.

not at all in a car they're very necessary noisy environment, little volts
DC, less than ideal wire runs, and many items that add EMI/RFI. I'm not
nitpicking just pointing things out.

You just completely ignored what I said. You're talking about the RCA wires
picking up EMI/RFI. I'm telling you that that particular source of noise is
completely overwhelmed by road noise, "installation noise", and power supply
noise. Even if you were to be able to completely eliminate the noise picked
up in the wires, the overall noise floor would remain unchanged.

"Mark Zarella" wrote in message
...
Your reasoning is circular. My first question to you was why does
higher
voltage reduce wind and tire noise. Your reply was that it allowed
you
to
turn your gains down. Then I asked why turning your gains down
reduced
noise. And you reply that the large input voltage leads to less
noise.

So now that you've brought us back full circle, I still have no idea
why
the
concept of gain came into the conversation. So I'll ask again,
because
I'm
a masochist...how does increasing the voltage reduce wind and tire
noise?

I never said it reduces wind & tire noise just background and EMI/RFI,
the
wind & tire noise is handled by SD.

But the noise that you're referring to is miniscule compared to the other
more prominent sources of noises. In other words, it makes absolutely no
difference because the noise floor is determined by road noise and grounds
more than anything else.

agree but you still need the bigger voltage differences to keep the
electrical noises like alt down.

"Mark Zarella" wrote in message
...
The discussion has consisted of you and others being nitpicky about
noise
levels, which are entirely dominated by power supply issues,
grounding,
and
road noise. Noise picked up in the RCAs along the way to the
amplifier
is
negligible. Therefore, high voltage preouts are useless.

not at all in a car they're very necessary noisy environment, little
volts
DC, less than ideal wire runs, and many items that add EMI/RFI. I'm not
nitpicking just pointing things out.

You just completely ignored what I said. You're talking about the RCA
wires
picking up EMI/RFI. I'm telling you that that particular source of noise
is
completely overwhelmed by road noise, "installation noise", and power
supply
noise. Even if you were to be able to completely eliminate the noise
picked
up in the wires, the overall noise floor would remain unchanged.

but the reason for the preamp voltage is to keep the electrical noise down.
I'm not talking about the road/wind noise.

"Captain Howdy" wrote in message
...
I don't think Tha Ghee is keeping up I think he's looking thru purple
tinted glasses.


if you're going to crack on someone at least be original, is that hard for
you??

But the noise that you're referring to is miniscule compared to the
other
more prominent sources of noises. In other words, it makes absolutely
no
difference because the noise floor is determined by road noise and
grounds
more than anything else.

agree but you still need the bigger voltage differences to keep the
electrical noises like alt down.

sigh Nevermind.

You just completely ignored what I said. You're talking about the RCA
wires
picking up EMI/RFI. I'm telling you that that particular source of
noise
is
completely overwhelmed by road noise, "installation noise", and power
supply
noise. Even if you were to be able to completely eliminate the noise
picked
up in the wires, the overall noise floor would remain unchanged.

but the reason for the preamp voltage is to keep the electrical noise
down.
I'm not talking about the road/wind noise.

sigh Nevermind.

No not usually you dont!!!!...
They didnt have hgh volt radios untill the last 5 years or so..
so if you cant get noise out without em then your saying
all the systems I have done before there was high volt radios
were all noisy...

I beg your pardon..
I dont think so!!

I have been installi for 30 years
and from an installers point of view I dont care if it is a high
volt radio or not... It is certainly NOT neccisary!!

Tha Ghee wrote:

agree but you still need the bigger voltage differences to keep the
electrical noises like alt down.

You got me there, I couldn't think of anything dumber then that.


In article , "Tha Ghee"
wrote:
"Captain Howdy" wrote in message
...
I don't think Tha Ghee is keeping up I think he's looking thru purple
tinted glasses.


if you're going to crack on someone at least be original, is that hard for
you??

"Captain Howdy" wrote in message
...

You got me there, I couldn't think of anything dumber then that.


no your cracks are dumb mine are creative, I doubt that you see the
difference though...I forgot who I'm talking to.