Amp decreases output when volume is high

[mrpep]

I've had my setup for about a year now and no issues but now all of a sudden when I turn it up high the bass cuts off and as soon as I turn it back down the bass comes back in. I can't play bass at high volume. I have a alpine MRX-M100 amp , a second battery in parallel, 4 gage power, 1 10" sub 600 rms, kenwood HU. No big 3 just a plain set up. What could it be?? All working looks good and solid.

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[Boomin_tahoe 5,000+ posts]

Loose wire somewhere.....is the gain set right?

Also....if the big 3 isn't done yet, as you stated it isn't, you could very well be starving your electrical,....not providing enough juice for the amp and thus shuts down at high volume.

I highly suggest doing the big 3 1st before adding anything audio.....and this is a perfect example why.

 

[mrpep]

Loose wire somewhere.....is the gain set right?
Also....if the big 3 isn't done yet, as you stated it isn't, you could very well be starving your electrical,....not providing enough juice for the amp and thus shuts down at high volume.

I highly suggest doing the big 3 1st before adding anything audio.....and this is a perfect example why.

Weird thing is it's been running well for a year without big 3. How could it suddenly need it? Could it be ground ?

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[Boomin_tahoe 5,000+ posts]

Weird thing is it's been running well for a year without big 3. How could it suddenly need it? Could it be ground ?

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Have you cranked the volume before? Yes, I would check ground, every connection you can get to.

 

[mrpep]

Have you cranked the volume before? Yes, I would check ground, every connection you can get to.

Yeah I crank it all the time ... I'll check connections again tomorrow and report back.

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[Louisiana_CRX 5,000+ posts]

Could be bad rca's as the voltage increases from the deck the resistance decreases ..usually the result of older solder joints also the same could hold true to inputs on the amp

 

[trumpet 5,000+ posts]

Monitor the voltage at the amplifier when the volume is turned up. Run the engine and also be sure the voltage at your secondary battery is close to the voltage at the primary battery.

 

[audiobaun 5,000+ posts]

Corroded batter connections could be a possibility as well..Check you fuse connection also..Alt may be going bad,could have a bad battery in the mix..bad /corroded ground..Loose connections..Id start with all those.Id deff get that Big 3 done..Its worth the time and little money spent.As Ive always stated..It takes power to make power.Got to have supply for the demand

 

[evilmonstertruk Premium Member]

Could be your battery just getting older. Can't take it as well as it used too. Like everyone said monitor voltage and see.. Happy Father's day btw

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[BOOMINGRANDPA 5,000+ posts]

Yeah I crank it all the time ... I'll check connections again tomorrow and report back.

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yeah like they said could be batt or ground make sure it's not loos and no paint under it.. my amp did exct sme thing (but did it when i installed it) had sub volume to high on hu turned it down hasn't done it since..

 

[sfall]

Could be bad rca's as the voltage increases from the deck the resistance decreases ..usually the result of older solder joints also the same could hold true to inputs on the amp

That's not true. Voltage is inversely proportional to resistance. You may be thinking of current.

 

[mrpep]

With two batteries could it be both batteries ? Maybe ground needs cleaning and re tightening ? Kinda ***** but I have to fix

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[BOOMINGRANDPA 5,000+ posts]

With two batteries could it be both batteries ? Maybe ground needs cleaning and re tightening ? Kinda ***** but I have to fix

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i added screw to my ground but it was still basically the gain

 

[mrpep]

So I tested the batteries and the main engine battery is 14.4 volts and the second battery is 8.5 volts, it's also the one going to my amp which is also 8.5 volts. Shouldn't they both be 14.4 since they're parallel? Or is it possible that the second battery going to my amp had a poor ground. Or the battery is going dead. The battery is only 2 years old .

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[Boomin_tahoe 5,000+ posts]

8.5???!! I'm pretty sure that battery is dead. So you found the issue @adulbrich