Amplifier Makes High Pitched Noise

[NorthShore4Runner]

I'm looking at a very good deal on a used 500W Alpine amplifier. Original owner says that it works fine other than a high pitched noise that it makes when in use.

I don't know much about car audio, could this be an easy fix or should I walk away?

 

[Whitson Metalworks]

I'd walk. Not only because I can't stand high pitched noises, but, amplifiers aren't supposed to make any weird noises so something probably isn't right and you'll be looking for another good deal before long.

 

[BrianSD_42]

One of these is true ...

A) owner doesn't know car stereo and installed it wrong but maybe the amp is good

B) Amp is actually bad

How much?
What exact model?
Did you already buy speakers and if so which ones?

I'm sure I could help advise you into something better for a similar price.

 

[NorthShore4Runner]

One of these is true ...



A) owner doesn't know car stereo and installed it wrong but maybe the amp is good



B) Amp is actually bad



How much?

What exact model?

Did you already buy speakers and if so which ones?



I'm sure I could help advise you into something better for a similar price.

It's an Alpine MRV500, he's asking $20 shipped. I haven't gotten speakers, I'm probably going to keep the stock ones for now. I am installing a Scion t1809 head unit as well.

 

[BrianSD_42]

I'm pretty sure I have that same amp.

I'll have to check.

What does he say to the question: is it functioning normally?

If the answer is well no. It makes a weird sound. Then well at least $20 isn't a lot to risk for purchasing an amp

 

[NorthShore4Runner]

I'm pretty sure I have that same amp.



I'll have to check.



What does he say to the question: is it functioning normally?



If the answer is well no. It makes a weird sound. Then well at least $20 isn't a lot to risk for purchasing an amp

He says it's fully functioning except for the noise. A bad ground maybe? I imagine something more serious would cause a total failure

 

[BrianSD_42]

could be.

1) Does it make the noise, I assume out of the speakers, even when no RCA plugs are connected?

2) Also, does it make the noise with the RCA plugs connected, the key in ACC, stereo turned on but with the engine off ?

That is what I would ask him.

If #1 is YES then I would lean much more towards a bad amp.

If #2 is Yes then it could be a bad ground although I'd be a bit skeptical and I'd lean towards a bad amp.

Basically it would be good to know what conditions does this sound occur (always, only with engine on) and does the pitch ever change.

 

[UnderFire]

Most of the time the amp is not the cause of a whining noise, it could either be an alternator whine he's getting, a bad ground, or possibly noise in the RCA's, a PICO fuse blown on the headunit is also a possibility if he's running a Pioneer headunit.

Even at 20$, I'd buy it, install it with good grounded RCA's and a solid ground, and if it ended up being bad, oh well, you can get your 20$ out of it super easy.

 

[02SE]

It could be that the seller has been listening at high db levels for so long, that the high-pitched noise he's hearing, is tinnitus setting in..

There are some morons driving around with their "music" playing so loud, that it can literally vibrate the house, and set off my car alarm from several hundred feet away.

I look forward to the day they are deaf, and no longer annoy everyone within a 1/4 mile of their POS car.