RCA Grounds

OK, here's the deal....

Trying to work through this ground loop saga (thanks for all the responses to my former post(s)) I rewired everything behind the dash, which in a Miata is VERY small..and it got WORSE!!!!!

I gave it a good think and have come to the following conclusions:

Get rid of the car (NOT!)
The whine is worse through the AUX in than through the plyer, leading me to think that the RCA inputs to the RIO are the source of the noise.....which is then 'leaking' through to the player.

It seems that when I even touch the shrouds on the RCA inputs the noise level jumps...and when they are touching each other, or even close, the noise gets worse...

SO, I have concluded that the noise originates from the RCA input jacks, which perhaps are not grounded properly.

Thus, my questions are:

Is this possible?

Would it help the issue if I shrink-wrapped the exposed shrouds in some sort of insulation (electrical tape, maybe)

Is it possible that there connection to the sled is not right and I need to do some tinkering?


Thanks to the usual suspects so loyal to this product in advance for helping me out!!!!!

ED

Is this possible?

Would it help the issue if I shrink-wrapped the exposed shrouds in some sort of insulation (electrical tape, maybe)

Is it possible that there connection to the sled is not right and I need to do some tinkering?


When it comes to noise I'd be hesitant to declare anything impossible...

Anything unused should be covered... Try electrical tape or shrink tubing. For the RCAs you could also try muting plugs (get the mating sockets and solder wire from center to shield, so that the center pin is attached to ground)

If it got worse when rewired I'd suspect either something not properly connected, maybe at the sled connector, or that you have a severe noise generator somewhere and that you got the wiring closer to it now...

Inspect the RCA wires as they connect to the sled connector - also check the connections to the connector on the inside of the empeg.

Have you worked through the noise problem solving flowcharts Tony links to in the FAQ?
Are you using the stock harness for ground? What happens if you temporarily attach a [16 gauge or thicker] wire between the empeg chassis and a good ground point?

/Michael

Went through all the guide for ground loops...

yes..i did try to ground the sled to the ground point on the amps...no change...

it is definately the AUX in rca's on the Rio...for whatever reason, when/if they move in the dash and get in the wrong position the noise is horrible...so im thinking that perhaps these inpusts are not grounded correctly......i am going to have to take the sled out and give the rca's a good look-over and hopefully i can sort this out

again..in aux mode the noise is several time worse than in player mode...thus my gut feeling on the rca's

oh..and btw..the AUX are in fact connected to a Sony cd receiver, so they are not sitting out there exposed...

What's the situation if you unplug the AUX ins from the Sony?

/Michael

SO, I have concluded that the noise originates from the RCA input jacks, which perhaps are not grounded properly.

Although you are currently working on the right premise (narrow down connections and see if you can make the noise change as you alter the connections), I don't think you have enough information to support that particular conclusion yet.

Just because fiddling with the RCA connectors changes the amount of noise doesn't mean that they "originate" the noise. Although that very well could be the case, I think what's more likely happening is that there is a fault somewhere else the system (perhaps someplace completely different that's got a bad ground) and that touching/moving the RCA connectors increases their potential to ground and makes the ground loop worse.

Can you list each and every diagnostic step you've performed so far, including all wire gauges and connection points? Also, please list everything that you've already ruled out, and why. For instance, did you check for the rolloff capactiors? Listing that information might help us offer suggestions of things you haven't tried yet.

Tony,

Sadly, yes...my friend has an Empeg and i swapped out my HU for his and there was very very littl whine through the AUX input...i am very sad for it means that that there is something definately wrong with my HU and, alas, customer service is no more....

Any suggestions???

Ed

If you plug in the RCA's very slowly - can you make the center pins touch the female connection and flow music, without having the outside shield make contact?

Sounds silly, but has worked for me once in an old Jetta. Ultimately it turned out my amp was not grounded as well as I thought.

hmmm havent tried that! have to rip the dash apart first will let you know how i made out..thanks!

i swapped out my HU for his and there was very very littl whine through the AUX input.

Ah, very good diagnostic. That could very well mean something bad with the aux input. Contact Rob S. and see if he can do something for you. Since it's out of warranty it won't be free, but if he thinks he can fix it, it might be worth your time.

Do you also have a problem with your aux in levels being too quiet, but if you turn up the volume on the other head unit then you get distortion?

I didn't have much alternator noise, but I had the aforementioned problem, and I spoke of it to Hugo, and he said "Hm, that's odd, it sounds like the outputs from the other head unit aren't grounded properly."

So, I eventually got around to taking off a bit of the dash, and there was a "speaker to line level" converter in between the other head unit and the empeg. I tried putting the RCA grounding leads that came with my Mk1 in there and it worked like a charm.

What happens if you actually properly ground those RCAs?

Richard.

Thanks Tony!....er...how exactly would I contact Rob S.??

No...I have plenty of output from the other head unit...just lots of alternator whine as well...like i said above i have swapped my Rio for my frineds and the noise was negligible.....thus it must be my HU..took it apart and all of the wires are tight in their respective places, so i must be one of the 1000000000 of little silicone things that make this unit work...hopefully customer support is still around to take a look at this for me!

how exactly would I contact Rob S.?

Email [email protected] In another thread it was mentioned that it's somewhat slow to get answers right now, most likely due to Rob getting lots of work.

/Michael