Hey guys,
Just got my new 4x130wrms jaycar amp delivered :D.
Anyway i'm hooking this baby up to 2 JBL GTO's 100wrms and a pair of jaycar splits 60wrms up front.
My question is, is the sensitivity the same as gain control and, by having full gain, does that mean at it's loudest point 130wrms (in theory) would be coming out?
So if i were put the sensitivity at half way, does that mean it'll only pump out 65wrms?
The input signal says up to 5v, which is what my hu puts out. But i'm guessing voltage is relative to volume on the head unit?
Eg. 50% volume on the headunit would be sending out a 2.5v signal? And if i were to go over that with sensitivity on half, i woud get clipping?
Is that how it works?

Hey guys,
Just got my new 4x130wrms jaycar amp delivered :D.
Anyway i'm hooking this baby up to 2 JBL GTO's 100wrms and a pair of jaycar splits 60wrms up front.
My question is, is the sensitivity the same as gain control and, by having full gain, does that mean at it's loudest point 130wrms (in theory) would be coming out?
So if i were put the sensitivity at half way, does that mean it'll only pump out 65wrms?
The input signal says up to 5v, which is what my hu puts out. But i'm guessing voltage is relative to volume on the head unit?
Eg. 50% volume on the headunit would be sending out a 2.5v signal? And if i were to go over that with sensitivity on half, i woud get clipping?
Is that how it works?

Best explained here - http://www.caraudioaustralia.com/forums/index.php?showtopic=35875

Yes, sensitivity is the same as gain controls. No, by having gains turned up all the way does not mean it is at its loudest point. It means the amp is trying to pick up a very weak signal from the head unit; ie high sensitivity. As you have 5 volt preouts, your head unit has a pretty strong output signal (next step up is 8 v preout, which is about the highest I have seen around for car systems) so your 'sensitivity' will not have to be at its highest. Basically, you want your sensitivity to be set so when you have you HU volume turned up to the max, you amp is pumping out its max of 130wrms. Set the sensitivity any higher, and the amp will be reading the signal as a weaker signal and trying to produce a louder sound than 130wrms which it can't do. This results in "clipping" of the sound. Clipping = bad/hurt speakers.

Make sense? If not sorry.... Best look at link.

Oh ok, so my gain/sensitivity should be set pretty low with 5v preouts? Does having a higher sensitivity distort more at the same volume? ie. say my hu can go up to 20. At 10 i have the sensitivity on 4v. If i then lower the hu to 5, but increase sensitivity to 2v, will it make much of a difference?
Is it possible to limit the power being output to the speakers? Or is it merely, my HU on full on the recommended sensitivity will output the full wrms per channel, so once i've got the gain/sens setup it's just a matter of not going over half volume (on hu)?

Oh ok, so my gain/sensitivity should be set pretty low with 5v preouts? Does having a higher sensitivity distort more at the same volume? ie. say my hu can go up to 20. At 10 i have the sensitivity on 4v. If i then lower the hu to 5, but increase sensitivity to 2v, will it make much of a difference?
Is it possible to limit the power being output to the speakers? Or is it merely, my HU on full on the recommended sensitivity will output the full wrms per channel, so once i've got the gain/sens setup it's just a matter of not going over half volume (on hu)?

Well the gain should be set fairly low with 5v preouts.

The reason higher end h/u tend to have higher preout voltage (for instance, all Eclipse units above entry level have 8v preouts) is because it is better. Reason why it's better is that it reduces induced noise. For instance, with engine whine etc you will find it becomes louder as you increase the sensitivity on the gain. Therefore, the noise floor is decreased by decreasing the sensitivity. However, a unit with 2v preout will have a higher noise floor typically, as it has the gain turned right up so all that noise is quite loud aswell.

Using your example, if you volume is on a scale 0 to 20, your gains are set correctly and listening at a comfortable listening level of 10. Lets say it's a perfect world, and at this level your speakers are using half the amp power - 65wrms.
If you increase the amp sensitivity to 2v, then your amp is maxing out at 130wrms at volume level 10. You can never turn you volume up higher than this really without distortion/clipping, which damages you speakers and wastes half the function of your voluem knob. Secondly, when you turn up/down volume between 0-10, each volume increment dramatically changes the loudness of your music.

What you want is the gain set so when you put the coluem at max, the amp is putting out maximum volume. There is no advantage, only disadvantage, by setting the gain/sensitivity on more than needs be.

Cheers for that, yeh at the moment the gains are set pretty high, 3/4 i think, so at 10 volume (my headunit goes to 50 or 100) it's freaking loud, had it to 15, whole car shaking to bits, thats with my old amp too :badgrin: .
Cheers to micjaiy who gave me an idea on how to tune it properly.

Well amp is in and the music is crystal clear!
Got the sens set at 1/3 and 1/4 on my BOSS amp for the subs. I have to turn the sub down on the hu otherwise it drowns out the speakers too quickly. I've cranked it up abit and can't hear it distorting,though i can't really hear much at that volume lol.

I know have 6.5V pre outs and the gains on my amps are on the minimum, I have max volume of 40 and can probably only turn it up to 25 or 30. Pity Audison SRx amps only take 5V :doubt:

Now I have to put it all in the VW...