That's where you adjust your gain down...

 

if you adjust your gains to a numerical level lower than the maximum
voltage, you'll aggravate the problem further. The concept of adjusting
up/down is a little tricky, because as you increase the number (if the gain
control is numbered with voltages), you decrease the amp's sensitivity,
which is what you need to do for higher-voltage headunits. However, you
can never reduce the sensitivity below the maximum input voltage of the
amp. If your amp's input sensitivity (gain) is adjustable from, say 0.2v-5v,
you will drive it into clipping with an 8v signal no matter where you have
the gains set. However, you won't see those 8v without cranking the
headunit all the way up, so the headunit will work perfectly fine with the
amp if you don't turn up the volume past where it produces 5v. On the
other hand, that means you're gaining no benefit from a headunit the
produces 8v rather than 5v, all else being equal, including assuming that
both headunits' preamps produce a clean, unclipped signal at 5v. Of
course all else is rarely equal, and most headunits probably do not
produce a a clean unclipped signal at their quoted maximum preout
voltage, so it could still be worth having a headunit with a max preout
level greater than the max input level of the amp if it means it does in
fact produce a clean signal at the maximum voltage.
hope this makes sense...

 

Again, this is where tuning comes in.

Sure, my CD7100 will crank the volume control all the way to 80 (or 70, I think). I'm not sure, but I know that I don't turn it over 60.

When tuning your system, you should set the volume control to 80/85% max and adjust your amps to be the loudest you want it at that point (this means loudest with no clipping/distortion).

Given that I've yet to see a high-end amplifier that was not able to handle 8V inputs...

 

how about the Audison LRx 2.150?
"Input sensitivity 0.2 - 5 VRMS"
http://www.audison.eu/xml/products/pdf/aud...lrx2manuale.pdf
look, I'm not trying to make this a pissing match. Incorrect facts get
posted here, and then other people get bad info. I was trying to post info
here that would be helpful to people.

 

LoL...

Alright, you got me.

My LRx seems to handle the 8V pre-outs fine though... It's all about tuning. I'd rather have the higher pre-outs and less HU/Amp distortion because the gain on both (volume on the HU = gain) is lower to achieve the same output. Just my $0.02.

 

Sorry to jack this thread, but dude , sputnik, please don't talk about information you don't know about. When you Set "gains" on an amp to do it properally and professionally you use a multi meter set at AC, then you check how many ohms your going to hook up , then your determine the input voltage and test to check your clipping point... yes 8v's is good on some applications, but there's a reason why every radio out there doesn't have it. Yes Eclipse does make some higher end radios, but they use 8v pre-outs to match with their amps. If you increase the pre-out voltage to an amp that is 4-5v stable input and you drive that to 8vs, it's the sammmme thing if you put to much power to a speaker, except in this case it's probably a more expensive peice of equitment such as an amp, which eventually can blow the speakers, and can have a bad effect on the ground of the radio (causing ground loops) - friendly information on 8v pre-outs. No harm intended.

 

You're right. I know nothing about electronics, really. And I've never professionally set up an install, nor seen one done, nor even been friends with professional installers.

 

Matching a 8V pre-out to an amp with a lower gain setting range (e.g. up to 5V) is fine as long you keep the volume setting on the HU low"er". Usually, the ear drum would be the first to "clip" rather than the amp :-)

8V pre-out simply means that at max volume, the HU outputs 8V. Now assuming the HU volume dial increases linearly and has 60 steps, at 30 step the HU is roughly sending 4V to the amp. The amp in turn "amplify" that voltage and send it to the speaker.