4 Channel Amp from 2 RCAs?

[BigJoe]

Nope, mounted to a couple of battons and still have the whine. Could it be anything like a nip in the power wire etc?

 

[Pumesta]

Are the rear speakers mounted to the same metal panel as you have earthed the amp to. I don't think a nip in the power cable would cause it but if you have a brake in the insulation of the power wire you should address that ASAP before you have an in car fireworks display. Another idea that might narrow the problem down, swap the speaker wires so the rears are running off the front channels and vica versa. If the noise then moves to the front speakers, we can at least rule out the rear speakers and the wiring to them

 

[BigJoe]

@Pumesta thank for all your help so far,

The rear speakers are mounted in the stock locations in the door panels, i might try all the speakers on by one....the amp worked perfectly until i added the rear set.

I have the amp mounted to a couple of battons and the earth wire checked (dont look loose or damaged)

The RCS are down the left of the car and power down the right, the speaker cable for both driver side speakers are close enough to the power wire but didnt have any interference when i was only running the fronts.....

 

[pablo]

Id bin the rear speakers personally, not worth the grief!!

 

[BigJoe]

Thanks Pabs! I have thought about it to be honest but I would still like to get to the bottom of the problem tho,

I have no doubt it something simple and stupid that I have done...
...

 

[Cartunes]

Whine pretty much only ever comes from either differing earth potentials or insufficient screening in the RCA's - Either the head unit and amplifier are earthing at different potentials or the RCA's are passing a noisy component like a Body Control Module - I had triple screened RCAs in my car, but as they passed a smart fuse box, they picked up interference from the lights - I moved the lead by 50mm and the noise stopped.

Does the whine get faster with faster engine revs?

Is your earth point cleaned through to the bare metal? If not, get a wire brush, or small screwdriver and scrape all the paint off around the earth terminal - is the earth eyelet securely crimped and or soldered? If it is even slightly loose, it can cause whine.

Once the earth point is spotless, tight and complete, you can cover the bare bits with paint or nail polish to stop it going rusty.

Edit - Y splitters do not cause whine, in fact, they may make it worse as the voltage is halved per input.

 

[BigJoe]

oooooohhhhhhh, you might have touched on something there....the RCA's are ran beside the CCM module that hides under the passenger seat in a Passat, and beside a whole pile or other wiring!

Its possible these were moved when the other set of speakers were wired in...

I'm not using any Y splits yet, and the earth point is clean (sand paper down to metal) the the eyelet is crimped and is tight when pulled. I have had to drill a hole in the eyelet and screw this to the car as I dont have a bolt hand to go through it!

 

[pablo]

Ys (in my experience) are usually noisy too so Id make sure the noise is sorted before adding them.

 

[Cartunes]

oooooohhhhhhh, you might have touched on something there....the RCA's are ran beside the CCM module that hides under the passenger seat in a Passat, and beside a whole pile or other wiring!

Its possible these were moved when the other set of speakers were wired in...

I'm not using any Y splits yet, and the earth point is clean (sand paper down to metal) the the eyelet is crimped and is tight when pulled. I have had to drill a hole in the eyelet and screw this to the car as I dont have a bolt hand to go through it!

Sounds like two possible candidates! I'd get a bolt in that earth too - a screw will never give the torque it requires in my experience (28 years of Car Audio, man an boyyyyyyy)
Throw the RCA leads over the seats - alongside nothing to see if the noise abates too!

Enjoy

 

[-Pete-]

agree with del

get a solid earth point in the floor pan of the car, not the sides or anywhere else, if you can (biggest one piece panel and gives best earth location) with a nice bolt and good solid ring terminal or dedicated earthing block. that will rule that out.

if you want to go the extra mile, beefing up the battery earth can also help. i had no end of grief with noise in a previous car and this simple upgrade eliminated it

also just picked up on one of the pictures, if you are running one set of rca's should the switch not be set to 4 channel? it shows it still set to 2 channel in your picture? or maybe i just scanned this thread too quickly? if so , my fault there.

 

[BigJoe]

front seat is out and the floor is coming up to see if the RCA is beside something that is causing an issue....i will let you all know the outcome!

 

[pablo]

if you have a spare set plug them in and up the middle of the car just to rule it out. might save you ripping the floor out!

 

[BigJoe]

I have tried all of the suggestions and still nothing...

RCA up the middle of the car - Same noise
Re -crimped the ground wire and used a nut and bolt to ground - Same noise
Checked all speaker connections - (disconnected and reconnected) same noise.

SO.....i have also noticed that the noise comes on with the ignition turning on, but without the car being started.
A search on the net suggested earthing the RCA cables to the headunit body, does anyone have any opinion of how good an idea this is and how likely it is to work??

I will literally try anything at this point!

 

[Cartunes]

RCAs are usually earthed to the body of the head unit.

Try a ferrite on the live supply of the head unit. What brand is the head unit? Have you told us?

 

[BigJoe]

its a new Kenwood bluetooth jobby

 

[Cartunes]

Hmmmm, no need for a ferrite on that unless it is faulty - is there whine through the non-amplified speakers? (disconnect amp and listen if you have speakers running off the head unit)

 

[BigJoe]

I dont have any non-amped speakers anymore....i have just tried the RCA grounding trick and the whine is GONE!

so, is it ok to leave the setup like this or could something else be done more permanently???

 

[Cartunes]

leave it! Job done........ shouldn't have needed this as the Kenny should ground what comes in on that shield - maybe the shield wasn't crimped or soldered properly - sods law!

 

[BigJoe]

sods law is right....I had such a nice and neat install at the start before all this ballsing about...I wonder why it suddenly stop being quiet and started being whiney...
Is there a fuse/resistor in the HU to stop this happening?
Is it possible i have blown something during the install etc?

@Cartunes thanks for all your help!

 

[Noobaudio79]

For those who say you can't run 4 speakers and a sub on a 4 channel amp I call b.s. run your left front to the left rear speakers by using a wire splice then do same on the right side make sure the fronts speaker wires run to the amp and the rears wires splice into the fronts. Now at the amp connect both the left and right + speaker wires and connect the - wire to the negative terminal on channel 1 use channels 3 and 4 to bridge your sub.. now you have 4 speakers and a sub on a 4 channel amp. You just ran all 4 speakers in parallel.. make sure you do the math and make sure your ohms equal to your amps nominal impedance if it's higher or lower than your amps nominal your gonna break ****.

To figure out your impedance Number of speakers divided by the total of ohm.
If you have 2x speakers @4 ohm = 8 ohm divided by two is 4 ohm. 4 speakers like mine @4 ohm each =16 16÷4= 4 ohm and a 4 ohm sub

I am running 4 Pioneer TS-600M 6.5" in the doors and a 12" kicker off of a El cheapo amazon SSL EV 400watt 4 channel amp. 2-8ohm stable.

 

[pablo]

not sure who called BS and its been a while, but if the amp is powerful enough then it can do this but you half the power to each speaker when in parallel iirc so youd need enough juice in the amp to compensate? Same principle when running 2 subs off a 2ch amp, they generally run better in bridged parallel than on sep channels.

you also lose control of adjusting the volume of each speaker independently which might be fine but might not give the control youd be after. Always favoured 2 amps myself, a 4ch for the speakers and a dedicated amp for sub(s)