I Made A Mistake.... too much power. help please

[Nico Koutouzis 10+ year member]

Hey guys I bought type r components and coaxials, but I made the stupid mistake of buying an mb quart that puts out 125 watts per channel when the coaxials can only handle 100. Now I am thinking that I should have bought the 4x80 mb quart amp. Is there any way I can set all the filters/gains/ whatever else the amp has to allow only 100 watts out at full tilt? I really dont want to blow anything haha. (ik im a noob just help me and dont bash)

Thanks

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[sacsking916 5,000+ posts]

check the gain setting sticky (iirc there is one in the wiring section). you do the math and get the RMS you want and that is how you will be able to set it at 100 instead of 125

 

[-01limited- 10+ year member]

Yeah, You dont have to run the gains to where the amp is putting out max wattage. Just back off them a little. In this hobby is better to buy with overhead so you can upgrade components down the road and dont have to buy another amp.

 

[JoshC 10+ year member]

it was a good choice, set it with a DMM

 

[wickedwitt 10+ year member]

The gain isn't an output knob...it is a voltage input matching device. He'll still be putting whatever that amp will truly put out, but as long as it isn't clipped, he shouldn't have any probs with them. We always run 3-4x RMS on mids/highs and are just very careful with both gains, and crossover settings.

 

[DonH 5,000+ posts]

what head unit do you have? normally setting the gain to match your HU MAX rca voltage output is a good rule of thumb, lets say its 2v. setting your gain to anything under 2v like 1v will cause distortion at higher levels, setting your gain to 3v or 4v will cause your amplifier to output less "power" as its waiting for a 3 or 4v signal that will never come from your headunit. hope i helped in any way. a little knowledge on what exactly a "gain" control is goes a long ways. i hate it when people think its a volume control knob.

 

[Nico Koutouzis 10+ year member]

I dont even think the onyx 4.125 has a gain control. I dont see it anywhere

 

[THATpurpleKUSH 5,000+ posts]

I dont even think the onyx 4.125 has a gain control. I dont see it anywhere

FAIL.

do you not have eyes?

its marked LEVEL, its to the left of the BASS EQ KNOB.

The point of the gain or input level is to match it with the output level of the headunit. If your headunit has 2.5v preouts then you set the gain to 2.5v, if the h/u has 4v, you set the amp accordingly. The problem comes from the marking system or lack there of used on amps. Some will have numbers but most have nothing at all and are very unclear of the setting, thats why you should set it with a dmm and ideally an ocscope to find what level the headunit clips at.

 

[mylows10 5,000+ posts]

it does on the side where all the controls are

 

[Nico Koutouzis 10+ year member]

haha my bad thats why. I quickly glanced for the "gain" and skipped right over "level" yea im an idiot. I cant believe i did that. anyways...... I have a dmm and I know there are stickies to make sure ur gains are set correctly with it. (oscope is obvsly better but i dont have one). So how am I gonna get this thing to push 100 watts instead of the 125 is the real question.

 

[THATpurpleKUSH 5,000+ posts]

 

[Nico Koutouzis 10+ year member]

edit: read post below

 

[Nico Koutouzis 10+ year member]

But is this for subwoofers or speakers? should I still use the 50-60 hz cd for the speaker amp?

 

[trumpet 5,000+ posts]

OMFG don't you dare hook up that amp on those speakers

No, really, there's absolutely nothing wrong with using that amp on speakers rated for less RMS power. Chances are good neither Alpine nor MB Quart have published exactly what that RMS value means and how they derived it. Your Onyx amp probably isn't going to put out 125 watts for more than a few moments anyway, which is typical of any amplifier unless you're going to be listening to test tones.

 

[RAM_Designs 5,000+ posts]

It's a lot easier to run a more powerful amp than you really need. Simply set the gains at bare minimum and move up from there if need be. You're more than likely not going to stress the amp running those speakers, and you'll be able to tell when the speakers are taking too much abuse(they'll probably be too loud by that point).