Why are the volts so high from my amp?

[bug splat 10+ year member]

I decided I was going to set the gain correctly on my amp using that tutorial above.

Here are the specs

RF Punch 325.1, mono (400w RMS @2ohms)

2 kicker 07CVR02's (2ohms draw from amp)

Panasonic hu (1.9V from RCA each)

14.1V to the amp from battery

I did the math and came up with 28.2V. Fine, great, grand, lets move on. I then downloaded three test tones (35, 40 and 50) at 0db. I cranked my HU up as high as I listen (40/40) and left the HU bass at +2. I turned down the gain all the way on the amp, made sure the LP filter was on and removed the subs. When I played the 40hz tone and used my DMM I was getting a 42.0V feed at the lowest gain setting and when I turned up the gain I maxed out at 48.2. WTF . That is way to high and no where near where I need it? What did I do wrong? If I do the reverse math with those ranges I get around 1000w. That can't be right can it? I know RF amps are under rated but that is just to high. The only way I can get it down in to the 20's is to turn the HU down to 20/40. What gives?

Thanks

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[HellsRise 10+ year member]

Why do you listen to your music at 40/40?

 

[casper97ta 10+ year member]

Some head units can be turned up to max volume with out clipping. I cant say for sure if his should be turned up all the way or not. But anyway, Just set the gains by ear. Also, I would check and make sure your DMM isnt off

 

[icecreamman69]

well man your problem is that you have your bass turned up on the h.u. when your tuning your amp in useing the dmm you have to play either a 50 or 60hz test tone with all your h.u settings off like the bass needs to be at its lowest level or off and the loud should be off if you have it or not and then you set it to what ever voltage it should be then you can retune your deck in the way you want it.

 

[casper97ta 10+ year member]

well man your problem is that you have your bass turned up on the h.u. when your tuning your amp in useing the dmm you have to play either a 50 or 60hz test tone with all your h.u settings off like the bass needs to be at its lowest level or off and the loud should be off if you have it or not and then you set it to what ever voltage it should be then you can retune your deck in the way you want it.

This is not true and dont spread false info. You need to read the Tutorial yourself.

here, learn something-http://www.caraudio.com/forum/showthread.php?t=63933

 

[phyphoestilic 5,000+ posts]

I wouldn't set at 40/40. I never go past 80% of the HU volume just cause the possibility it might be a clipped signal. Try setting it at 30/40 or maybe even 35/40. Of course with the max bass/EQ settings u plan on using, so i guess bass at + 2

 

[phyphoestilic 5,000+ posts]

also make sure the bass boost isn't used on the actual amplifier tho.

 

[bug splat 10+ year member]

Thanks guys. The HU really isn't that loud. Its only putting out 18wRMS per speaker so 40/40 is not that loud and that is why I wanted to set the gain while at 40/40. There is no bass boost on the HU and its only at #2 bass but since the HU goes by 2's its really +1 bass. I can turn up the gain to 3/4 on the amp and still get great sound from the subs. Any other advice on things to try? Could my amp really be putting out that much power?

 

[theCybe 5,000+ posts]

Not that much "clean" power, no.

Some headunits use the "bass" control to modify the preout voltage (instead of the actual signal)

You need a new hu brudda.

 

[bug splat 10+ year member]

Not that much "clean" power, no.
Some headunits use the "bass" control to modify the preout voltage (instead of the actual signal)

You need a new hu brudda.

Why? It sounds fine. My subs are not clipping at all and are VERY loud. The preout voltage is only 1.9 which is not high at all. Why would I need a new HU?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[Rich B 5,000+ posts]

Dont forget that RF typically underrates their amps by a wide margin, so basing your voltage output estimate on the rated wattage can result in it not putting out what its capable of.

If you have the birthsheet, try that instead.

 

[bug splat 10+ year member]

The birth sheet shows 412watts RMS @14.4v with 66.6%ef. So I figured around 400rms is a good amount for the 14.1V my car can provide and that is where I got my 28.2 target gain setting. The peek Watts is 1200+ but that number really offers no real world specs from what I understand.

 

[theCybe 5,000+ posts]

Because you power your doorspeakers with the headunit, and you said they're not loud enough until you turn the unit up to maximum volume.

Which probably causes a clipped signal, which is causing the trouble with your amp gains.

 

[bug splat 10+ year member]

Oh its plenty loud but not amp loud. I normally don't go above 30 and when I do its just when I want to show off a little but never for even a full song.

So should I disconnect the speakers from the HU and then test? Wouldn't that increase the Volts coming out of my amp?

OK last question......If it sounds clean and hits hard do I even need to try and fine tune everything? Should I just say "F-it" and enjoy it, because that where I'm at with this whole stupid gain thing:suicide:

 

[phyphoestilic 5,000+ posts]

like i said, make sure the bass boost on the amp itself is turned all the way down too.