Trying to understand 2V vs 4V preamp output
11-11-2005, 08:35 PM
#1
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Trying to understand 2V vs 4V preamp output Hi all,
Just trying to make sure I understand things right.
Let's say I have:
a head-unit "A" with 2V preamp output
a head-unit "B" with 4V preamp output
knowing that in either case, they would go to an amp.
Is the difference at the point where @ close to full volume, the output signal to the amp will be close to 2V of magnitude (A) and 4V (B) ?
Since amp are preset @ given gain and volume is controlled @ the head-unit, i see the signal from the head-unit being shrinked when the volume is lowered.
imho, that would imply that if I don't intend to do high volume use, nor enter and noise level competition, even with (B) I would never take advantage of the 2v-4v range since I would be listening to normal volume levels.
Is my thinking way off ????
If not, I rather save some $ on the HU I want to purchase.
Just trying to make sure I understand things right.
Let's say I have:
a head-unit "A" with 2V preamp output
a head-unit "B" with 4V preamp output
knowing that in either case, they would go to an amp.
Is the difference at the point where @ close to full volume, the output signal to the amp will be close to 2V of magnitude (A) and 4V (B) ?
Since amp are preset @ given gain and volume is controlled @ the head-unit, i see the signal from the head-unit being shrinked when the volume is lowered.
imho, that would imply that if I don't intend to do high volume use, nor enter and noise level competition, even with (B) I would never take advantage of the 2v-4v range since I would be listening to normal volume levels.
Is my thinking way off ????
If not, I rather save some $ on the HU I want to purchase.
11-11-2005, 11:40 PM
#2
It's input sensitivy on the amp, not gains!!!! There are some amps (none come to mind atm) that have both a sensitivity AND gain adjustment.
You use the sensitivity adjustment to match the amp to the HU output.
I would go with the 4V as it would help some in the noise rejection dept. Also look at the output impedance of the HU.. Lower is better. 50-100 ohms is good.
You use the sensitivity adjustment to match the amp to the HU output.
I would go with the 4V as it would help some in the noise rejection dept. Also look at the output impedance of the HU.. Lower is better. 50-100 ohms is good.
11-13-2005, 12:12 AM
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oddly enough, once you've passed a certain point, exceptionally high preouts (like 10 volts for example) can actually cause distortion. this is why eclipse HU's are rarely used by the sq competition heavies, because the eclipse HU's have very high preouts.
11-13-2005, 12:53 AM
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Originally Posted by GPz1100
It's input sensitivy on the amp, not gains!!!! There are some amps (none come to mind atm) that have both a sensitivity AND gain adjustment.
You use the sensitivity adjustment to match the amp to the HU output.
I would go with the 4V as it would help some in the noise rejection dept. Also look at the output impedance of the HU.. Lower is better. 50-100 ohms is good.
You use the sensitivity adjustment to match the amp to the HU output.
I would go with the 4V as it would help some in the noise rejection dept. Also look at the output impedance of the HU.. Lower is better. 50-100 ohms is good.
Thanks.
11-13-2005, 02:22 AM
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The idea is that the higher the voltage ( to a certain point ) allows you to achieve a higher signal to noise ratio. In theory the higher your S/N ratio is the less your distortion will be. Ive found that sources with high signal to noise ratio really only cuts down the 'buzzing' sound in the quiet parts of the music when the volume is turned up. In my opinion anything more then 5v is too much.
