Line Out Voltage too high?

jjohan35 · Post by **jjohan35** » Sat Feb 09, 2008 3:21 am

Hi folks,

I have an amp that has input sensitivity 100 millivolts to 4 volts. I want to upgrade to a particular head unit but its pre-outs are 5 volts.

Will this be a problem? Do I need to find a lower deck or higher amp? Thanks for any help.

JeremyC · Post by **JeremyC** » Sat Feb 09, 2008 4:44 am

No you can do it.

Set everything on the head unit to flat, put in a 1000 hertz 0db test tone, and hook a volt meter to the rcas. Now turn the deck up to 4 volts, and remember what volume you have it at.

When you adjust the amps input stage, turn the deck to the same volume.

Just remember anything above that volume COULD cause clipping. So don't go to far past it.

jjohan35 · Post by **jjohan35** » Mon Feb 11, 2008 9:57 pm

Thanks for the help. I'll try it out.

NorthQuad · Post by **NorthQuad** » Thu Jun 26, 2008 12:59 pm

Will running higher than recommended volts from the HU Output to the Amp Input fry anything? Or will audible clipping be heard before stuff starts to burn up?

There's a nice amp that went on sale in town and I can hardly hold myself back from buying it. But it's recommended Input is 4.0volts and my HU puts out 6.0volts if I remember correctly.

JeremyC · Post by **JeremyC** » Thu Jun 26, 2008 1:22 pm

Ok first, just cause your head unit says it will do 6 volts doesn't mean it will without clipping. You really need to check it to be sure.

Since you don't have access to an o-scope, just put in a 1000 hertz test tone (disconnect every thing first) and crank the volume to 3/4 and measure the output at the RCA. If its under 4 then your fine. If its above 4 then use the methods I posted earlier to help you set the gain.

Yes an input voltage thats to high can overload the input stage, and burn something up. But you SHOULD be able to notice some pretty crazy clipping (from the input stage) before you get to that point.

JeremyC · Post by **JeremyC** » Thu Jun 26, 2008 1:22 pm

double

Ryan from Ohio · Post by **Ryan from Ohio** » Thu Jun 26, 2008 3:05 pm

And if your going to do Jeremy's test you will need an analog meter. A digital wont display the sharp rises/drops in voltage where tis readable.

JeremyC · Post by **JeremyC** » Thu Jun 26, 2008 3:36 pm

Nah a digital will work for what I'm talking. The only real way to check for clipping is an o-scope. But since you don't have one, 3/4 volume is a pretty safe bet, as long as your deck stays below the rated output. If your getting 6+ volts at 3/4 volume you going to run into clipping in your decks output stage.

NorthQuad · Post by **NorthQuad** » Thu Jun 26, 2008 3:51 pm

Badass! Thanks Jeremy and Ryan.

I'll try and scrounge up some cash. $250 for an Alpine MRP-F550. It's gotta' be worth it, no?

http://www.alpine-usa.com/US-en/product ... l=MRP-F550

Too bad my funds are going every different direction at once. Land taxes, insurance, two mortgage payments at once. My account hasn't been this low in a long time. I really shouldn't even be looking at buying this right now but damn, $400 dollars off. It probably won't pan out but a fella can dream, right?

Again, thanks for the info.

Tim · Post by **Tim** » Fri Jun 27, 2008 12:16 pm

NorthQuad wrote:Badass! Thanks Jeremy and Ryan.
I'll try and scrounge up some cash. $250 for an Alpine MRP-F550. It's gotta' be worth it, no?
http://www.alpine-usa.com/US-en/product ... l=MRP-F550
Too bad my funds are going every different direction at once. Land taxes, insurance, two mortgage payments at once. My account hasn't been this low in a long time. I really shouldn't even be looking at buying this right now but damn, $400 dollars off. It probably won't pan out but a fella can dream, right?
Again, thanks for the info.

What are you gonna be running with it?
The price I saw is $450.00

Another thing to look at is it's rated output is at 14.4 volts. that may not be a problem.

Tim