$25 Headunit whines, can anything be done?

dimva · 07-06-2005, 12:35 AM

So I got this headunit for $25, and tried to install it in my car.

First problem I encountered is that it is slightly too big because of a stupid plastic trim that can't be removed (seriously, wtf were they thinking). Once I turned it on, I noticed that radio quality is horrible, but since I'm only going to use it in emergencies, I don't care much.

Then there's the whine. It's always there, but gets especially bad when I turn the motor on, and gets even worse as I accelerate. I really don't know what to do about this because all of the suggestions are for amps.

So I'm wondering if this could be because of the retarded common-ground wiring scheme that this thing uses. Here's a diagram. Yes, that's right, both negative speaker wires are connected directly to ground.

Of course, the install doctor says "many older cars actually connect the (-) negative terminal of the speaker to the metal of the car" , but this is a new car and I don't think it's designed for this. Or maybe I'm wrong and this doesn't matter? What do you think?

Also if you suggest to just buy a good headunit, what do you suggest? I don't need tape/cd playback, only need a radio for traffic info, and obviously require auxillary input.

kevinlekiller · 07-06-2005, 02:08 PM

You have a bad ground I guess, They used the speaker negative wires as the ground. Try connecting a wire from the metal casing of the HU to the metal of your car.

falconey · 07-06-2005, 02:28 PM

I would never connect the neg terminal of the speaker to the chasis. If that's been done to your car change it. The next things I'd do and that's in this order. Make sure your pc case or something metal in the pc is ground to something metal on the car. If that doesn't work which it should be the head unit. Take the ground lead from the head unit and ground it to something metal on the car and also ground the back of the head unit to something metal on the car.

kevinlekiller · 07-06-2005, 02:49 PM

Quote: Originally Posted by falconey

I would never connect the neg terminal of the speaker to the chasis. If that's been done to your car change it. The next things I'd do and that's in this order. Make sure your pc case or something metal in the pc is ground to something metal on the car. If that doesn't work which it should be the head unit. Take the ground lead from the head unit and ground it to something metal on the car and also ground the back of the head unit to something metal on the car.

I see you didnt read is whole post... The head unit doesnt have a ground lead, its a old style radio that uses the speaker negatives as a ground. And as for the

Quote:

and also ground the back of the head unit to something metal on the car

I already said that...
Check the diagram: http://www.zagraf.com/wiring.gif

stapan · 07-06-2005, 02:54 PM

Quote:

First problem I encountered is that it is slightly too big because of a stupid plastic trim that can't be removed (seriously, wtf were they thinking).

no the first problem you encountered is that you bought a Pyramid head unit that sells for $25 brand new

considering at least some profit margin for the manufacturer, some profit margin for the seller, assembly and packaging costs, and devoting so much development and production resources to the good looking faceplate...

I'm sure you can figure out how much $$ and resources went into actually designing and making the radio part of that thing.

the box of lucky charms on my kitchen table cost more to make and would probably make a better radio.

looks like that place has a return policy. send it back and get something like this or this .

falconey · 07-06-2005, 04:18 PM

Quote: Originally Posted by kevinlekiller

I see you didnt read is whole post... The head unit doesnt have a ground lead, its a old style radio that uses the speaker negatives as a ground.

It does have a ground lead out the back of the head unit unless of course the speaker(-) lead is for both speakers???? which in and of itself would force me to toss the radio into the trash.

Quote: Originally Posted by kevinlekiller

And as for the
I already said that...
Check the diagram: http://www.zagraf.com/wiring.gif

Well whoop-ti-do, you said something already so I guess I shouldn't reinforce anything you've mentioned because who would doubt you, lol.

kevinlekiller · 07-06-2005, 05:31 PM

Whats the point of rementionning the exact same thing? If he has doubt he just has to ask. (Lets not start a war we are all friends here

) Has for the ground lead, I didnt catch you at first, I tought you meant that you were thinking(lol) there was a single wire for the ground other than the speaker ground.

Bugbyte · 07-06-2005, 06:08 PM

You have a ground loop, which is why everyone is telling you to ground everything. Here is a link to a discussion on ground loops in the FAQ Emporium.

antimatter · 07-06-2005, 06:25 PM

Sledge Hammer

pancit175 · 07-06-2005, 08:01 PM

Quote: Originally Posted by antimatter

Sledge Hammer

I'd suggest an air chisel/hammer. Then buy a radio thats worth it.
And stop bothering me with every little detail

dimva · 07-07-2005, 12:21 AM

Well I grounded the back of the headunit to the car and nothing changed.

The way the ground is set up, I have the negative wires of each speaker as well as the ground from the stereo connected to the black wire from the wire harness. They are all connected in the same place, so I don't know how there could be a difference in potential. It is likely just this stupid configuration that is causing problems with electrical components in my car. It is also very hard to ground something directly to the chassis since almost everything is made out of plastic.

I think I'm going to throw this out and buy this instead.

Bugbyte · 07-07-2005, 12:45 AM

If your power wires run near your speakers wires, they could induce noise.

dimva · 07-07-2005, 01:29 AM

Quote: Originally Posted by Bugbyte

If your power wires run near your speakers wires, they could induce noise.

Yes, they do, but they also do in the stock headunit which is noiseless, and there's really nothing I can do since all wires are basically clumped together in the same place, especially where they enter the headunit.

pancit175 · 07-07-2005, 10:02 PM

Quote: Originally Posted by Bugbyte

If your power wires run near your speakers wires, they could induce noise.

Thats usually only true when you have an amp that has inputs that line up with large gauge power wires and the amp picks up that irradiated noise and then amplifies it. In the case of a hu stock or aftermarket, the lines going to the speakers are not going to be amplified again.

kevinlekiller · 07-07-2005, 10:09 PM

What do you expect from a 25$ head unit that looks nice. They have to cut on quality somewhere.

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