is my amp broken? whistling noise

[oshkoshbajawsh]

my set up

rockford p550.2 (550w bridged apparently)

alpine type r swr-1222d

pioneer 1300mp head unit

the sub is bridged (everything is wired correctly)

to get to optimum bass i have to have the amp gain set to about 70%

(HU settings bass+1, treb+0, fad 0, sla+0) loudness off

it will sound great for a week or so. then all of a sudden ill hear whistling and hissing coming from the sub and rear speakers. sometimes with bass sometimes no bass at all. i have checked all the wiring. if i turn the gain all the way down to 0, it will go away and i can turn it back up again and everything is fine until this hissing repeats a week later or so... what is going on? if i dont have the gain up it seems this amp is not powerful enough to get much out of this type r...

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[lionfamlee Premium Member]

Ok. Is your sub and rear speakers hooked up to the same or different amps? Just asking, becuase you said that you hear distortion from the rear speakers and sub. If they are hooked up to different amps and you are still getting having those issues; then your problem is probably not with the amp it something else. H/U, ground, etc. Have you checked the ground and where is exactly is the amp grounded (is it touching bare metal)?

 

[oshkoshbajawsh]

i apologize. the noise is only coming from the sub. i have redone the ground a few times, its fine. bare metal for sure. i even grounded the rca's on my pioneer deck

 

[IonRL205 10+ year member]

Does the noise seem to change as you rev your engine, like kinda seem to go with the engine revs?

 

[oshkoshbajawsh]

no its pretty constant no matter what when it is there.

 

[dragonrage 10+ year member]

I'm gonna say check your grounds and wiring. Try with a CD/MP3 player as the input if it's not too much trouble.

 

[lionfamlee Premium Member]

Ok. Some people have to ground their RCAs on their Pioneer H/U. Good ground, check. Ok where are is your run of power wire vs your RCA? 1. Make sure they are not close to each other(power wire/RCs), also make sure the RCA's are not close to any other vehicle wiring.

...What size power and ground cables are you using vs what is recommend for your amp? Fuse? Is the positive power wire connected to the positive side of your battery (make sure you have a fuse within 12 to 18 inches of the battery)?

2. Make sure your H/U is grounded correctly. By this I mean would not use the stock ground; I would make a new ground.

3. Wiggle the RCA ends at the amp. You may need to get a separate set of RCAs and run them from your H/U to sub to ensure it is not RCAs.

4 If still having problems, use a MP3 player and get a 3.5 stereo jack to RCA wire and hook the RC wire to the amp and play it. If it plays without any issues them it could be your H/U. I know you said sometimes it takes a while to notice it, so this can be tiresome.

5. If you can use a multimeter; check the ohm reading on your sub. Do this by changing the multimeter setting to the ohm symbol, take out your sub, connect the red to positive on your subs terminal and black to the ground on your sub...for each side. Give it a few seconds and see if the ohm reading is the correct ohm that your sub is rated at. Keep in mind a 2 ohms can be red as low as 1.6ohms and as high as 2.4ohms, same goes to 4 ohm, 8 ohm, etc. If it is way out of range or than there is an issue to your sub.

Let me know if you get in issues on any of these steps.

 

[lionfamlee Premium Member]

Edit...Comp issues..sorry for the double post! Message deleted.