Volume get quiet then goes back up on subs??

[jbl420 10+ year member]

idk what is going on but I have an older alpine head unit and Rockford rca wires and 4g power wire going to a Rockford amp from a second battery.

I had a crappy connection on the power wire going to the amp which loosened up so I obviously dident have it screwed down to the amp tight I also had a secondary ground wire which was on the battery post upside down.

so I fixed up both connections seems like my headlights don't flicker and my voltage meter don't drop way down and go back up now.

Only thing is the sound coming out of the subs seems to go up and down like one sec at 20 volume its pounding then the next few seconds later the subs are barely kicking hardly any bass then a few seconds later bumping again.

btw the amp is a 4ch Rockford amp I got both subs bridged @ 4ohm its a p450 and I also got a door speaker amp that is just a sony 600w 4ch

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[jrdnhsnbrg 10+ year member]

What is the total RMS output of your system? What size wire do you have running between batteries? Did you do the big 3?

 

[Chriszle 10+ year member]

Amp could be going bad.

 

[jrdnhsnbrg 10+ year member]

Amp could be going bad.

That's what I was thinking too, just was wondering if there was another electrical issue here. If he was running it on low voltage it's definitely possible.

 

[jbl420 10+ year member]

i had the stock alt replaced to 100amp a few months ago the wiring looked good and thick like 4g coming from the starter. im using a 0g qpower power wire coming from the starting battery to the back battery with 4g wire going to the amps. the rca's are from an old 8g fosgate kit that has since been replaced.

funny thing is like a week ago it was pounding i had .5 farad cap took it out last month added a second battery and seemed fine besides a burnt up wire from the main battery to the fuse block this happend once before so i took out the junky fuse block made my own cut the burnt wire back and seems normal wire isnt burning but if i turned the voluume up too much the voltage meter would drop and the headlights would slightly flicker but i was pounding and during the day the volt meter would obviously read higher and not move around as much.

the other day i noticed the subs wasnt on so i looked at the amp touched the power wire and it sparked alil i noticed it was loose from the terminal so i disconnected the amp wire from the battery and left the door amp hooked up .

So basicly since i fixed the connector on the power wire and fixed my battery ground yesterday im getting this problem

As far as rms the rockford is a p450 from what ive seen its 225 x2 rms bridged @4ohm and the sony is 60w x4 rms at @4ohm

 

[jrdnhsnbrg 10+ year member]

i had the stock alt replaced to 100amp a few months ago the wiring looked good and thick like 4g coming from the starter. im using a 0g qpower power wire coming from the battery to the back battery with 4g wire going to the amps. the rca's are from an old 8g fosgate kit that has since been replaced.
funny thing is like a week ago it was pounding but if i turned it up too much the voltage meter would drop and the headlights would slightly flicker.

the other day i noticed the subs wasnt on so i looked at the amp touched the power wire and it sparked alil i noticed it was loose from the terminal so i disconnected the amp wire from the battery and left the door amp hooked up .

So basicly since i fixed the connector on the power wire and fixed my battery ground yesterday im getting this problem

That spark you saw could have been 1 of 2 things-

1. Capacitors inside the amp recharging because they were discharged when the power cable was unhooked

2. Power wire bumped the ground wire or the chassis of the amp (chassis may be grounded on certain amps) and causing something inside the amp to go bad.

If you were running the amp on low voltage for a while that could have damaged it, too. If you have another amp that you can test in there, do it. If the problem persists with the different amp, try your original amp in a different system. You should be able to find the problem after that.

 

[Chriszle 10+ year member]

It could also be a loose or bad RCA cable.

 

[jrdnhsnbrg 10+ year member]

It could also be a loose or bad RCA cable.

Exactly why I suggested he try different amps

 

[jbl420 10+ year member]

well you would think fosgate rcas would last a lifetime gold plated connections ect but who knows i got a spare set of newer scorshe rca's i could just try them out.

funny thing is i dont have another amp i sold it . i have a guy with a sony xplod 10002 2ch max amp that wanted to trade but obviously fosgate is the better amp.

once i saw the lil spark and thought i stuck the wire back in i drove home unhooked the power wire from the battery and dident use the sub amp till yesterday when i secured the power wire back into the amp and tryed to bump for the first time

 

[jbl420 10+ year member]

idk it almost seems like the problem is random i mean it doesnt appear to do it all the time like yesterday i played it and the sub level seemed to remain the same

 

[neo_styles 10+ year member]

idk it almost seems like the problem is random i mean it doesnt appear to do it all the time like yesterday i played it and the sub level seemed to remain the same

The amp is most likely old and will need to be serviced soon. There may be an issue with the power supply section.

 

[jbl420 10+ year member]

ya I belive it was made in 2006 funny thing is the old 150s punch I had pounded still and it was like 20 years old.

So should I trade the amp for 20$ and a sony xplode 1000w 2 channel. ???. I think im gonna just try the rcas and if nothing then ya prolly from not getting a good connection it was getting not enough power