61 replies to this topic

[Carlzilla]

i have one of these, highly reccomend alpine amps, have 2 myself now


http://www.google.co...mp;ved=0CA8Q_AU

[Sam Walters]

Can i fire my input in on this?

I don`t think the Amp is at fault at all! Just well, the fact that the Amplifier your using the power your sub woofers is playing low frequencies only i presume...Meaning your not hearing the frequency of the whine transmitted through the signal feed.

What i suggest you do.

Unplug the RCA leads from both amplifiers. Turn it all on, run the engine, see if you can hear an audible noise then. I don`t think you well to be honest with you.

If there is no noise, plug them back in to the amplfiers and unplug the cable from the head unit. If there is noise now, its a case of poor quality RCA cables passing over a part of the cars loom i can imagine. If there is no noise, the shield earth of the head unit is poor, refer to my previous post.

Also another little something you can try. Bang the rca lead with no splitter into the 6x9 amplifier.

Edited by Sam Walters, 26 July 2010 - 06:58 PM.

[minilester]

engine whine?..... bad earthing!

go back and do it all properly...

Edited by minilester, 26 July 2010 - 07:16 PM.

[Sam Walters]

engine whine?..... bad earthing!

go back and do it all properly...

A bad connection somewhere no doubt, but i wouldn't rule out signal either.

[skaterava]

My earthing is decent though, i can't see how it can have a fault. The quality of the wire is good, it's sturdily fixed via a big ring connector and a nut and bolt to a patch of unpainted body.

the fact that the Amplifier your using the power your sub woofers is playing low frequencies only i presume...Meaning your not hearing the frequency of the whine transmitted through the signal feed.

The amp used for the subs is not on low pass, the frequency is undoubtedly lower than the 6x9's but it's not pure bass.

Unplug the RCA leads from both amplifiers. Turn it all on, run the engine, see if you can hear an audible noise then. I don`t think you well to be honest with you.

If there is no noise, plug them back in to the amplfiers and unplug the cable from the head unit. If there is no noise, the shield earth of the head unit is poor, refer to my previous post. If there is noise now, its a case of poor quality RCA cables passing over a part of the cars loom i can imagine.

I'll try this next, but i have to admit the amplifier in question has been knocked about a bit. There was a month in which it was not fixed down in the boot whatsoever. Stupid i know

Edited by skaterava, 26 July 2010 - 07:59 PM.

[Carlzilla]

I really would try going down the ground loop isolator route first. i have good quality RCA's, and very good electrical connections all round. I used to make a living being an electrician, and tried to route the rcas away from the loom. Fitted ground loop isolators to my car, never had the whining since.

UNLESS youre really intent on buying another amp.

[skaterava]

Well, i've only got tomorrow morning to work on it, i'm busy with other things for the rest of the day and then i'm off on holiday for the rest of the week, so tomorrow will consist of following Sam Walters' suggestions, and then when i return i will fit a ground loop isolator, as well as construct a proper box for the subs to provide that little bit more sound quality. Oh, and maybe a capacitor too.

[skaterava]

If the shield earth is poor, how do i fix this?

[minilester]

so, you havea good earth between the engine and body work as well, yes?

and all power runs are as short as possible?

your not cable tying the cables together to "clear them up" and getting a little "cross talk" from the power runs?

wheres ya sub by the way and a capacitor really wont help... trust me....

[skaterava]

Both subs are on the parcel shelf. Yes, all amp to body earths are good, as short as possible, sturdy and using good quality wiring. I tried Sam's method, and it seems the RCA is not to blame, as the whining/buzzing only begins once both ends of the RCA are connected up.

The earth at the head unit must now be checked. Unfortunately i'm only proficient with amp and speaker wiring, i'm a little confused at the mass of wires coming out the back of the stereo. How do i check the earth there?

[skaterava]

Bump?

[Carlzilla]

i wouldnt bother messing around inside, it may void your warranty

i swapped head units the other day
and out of interest i took a ground loop isolator out to see if it made a difference

despite the new one being brand new, nothing changed (as in it still whined).

Edited by Carlzilla, 28 July 2010 - 03:46 PM.

[Sam Walters]

The earth at the head unit must now be checked. Unfortunately i'm only proficient with amp and speaker wiring, i'm a little confused at the mass of wires coming out the back of the stereo. How do i check the earth there?

Make sure the RCA`s are plugged into the Amplifiers!

Unplug them from Head unit. Is the noise still there?

Oh and sorry for not replying lad, I do have internet on my phone so i can review the forums, however the silly browser will not let me select the correct input box to reply to posts.

Edited by Sam Walters, 28 July 2010 - 07:30 PM.

[skaterava]

i wouldnt bother messing around inside, it may void your warranty

i swapped head units the other day
and out of interest i took a ground loop isolator out to see if it made a difference

despite the new one being brand new, nothing changed (as in it still whined).

I just bought an isolator this morning... It'll arrive by monday.

Make sure the RCA`s are plugged into the Amplifiers!

Unplug them from Head unit. Is the noise still there?

No, if i remove the RCA's from either end (head unit or amp) the noise stops.

Edited by skaterava, 28 July 2010 - 09:35 PM.

[Sam Walters]

Head unit at fault i recon.


Try that and get back to me.