Humming Noise with aftermarket Chinese Stereo

davidnormanuk

Registered User
Hi all,

I've replaced my RNS-E Navigation Plus stereo with a chinese item as it wasn't cost effective to try and convert the original stereo to bluetooth. verything has fitted fine and appears to work ok other than a humming noise which I get as soon as the stereo turns on. I'm running the Bose System as standard. All the speakers work ok as well as the sub but I'm not sure what's this humming noise is about. Any thoughts?

Cheers
Dave
 

Euans2

Registered User
I cant really help you with an answer but any experience i've ever had with the Chinese stereos has always resulted in humming noises
 

davidnormanuk

Registered User
I fitted one in my a3. The only issue I had was having to move the power lead for the amp to a different plug. Everything else was perfect. Good sound quality, Sat Nav & Bluetooth. Everything worked as it should. That's why I went for another.
 
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Marky M

Registered User
As above, no issues with sound quality etc but also get a slight humming noise but only when the lights are on.
 

DrEvil

Registered User
Lights as in internal lights or headlights?

Could be some kind of ground issue. I have read that radio humming can be because the internal ground piece comes loose. I think I read about someone also putting in something to better ground the speaker connections. Out of interest are you Bose, non Bose, or half amped set up?
 

desertstorm

Moderator
Staff member
Moderator
VCDS Map User
As above that kind of humming is usually due to ground loop problems. If you have multiple earths in a system there can be very small differentials in the voltage and this superimposes itself on the signal. You need to check the power grounds and the signal grounds and make sure they are separate. Sometimes you may have to resort to using ground loop isolators.
http://www.ebay.co.uk/itm/4-CHANNEL...minator-REMOVE-FILTER-Universal-/361338813636
 

davidnormanuk

Registered User
Hi all, sorry for the delayed reply. I've decided to send the stereo back. After having a look at the earths and having to get wait on an adaptor for the aerial I decided it wasn't worth the hassle as the seller assured me this was 100% compatible with the Bose System. Has anyone purchased a chinese head unit where you don't have this hassle?
 

DrEvil

Registered User
Well, I got mine from iceboxauto - who sells the same Chinese stuff but he's based in Liverpool, picks up the phone quick etc. I don't have problems with humming on the unit I purchased, I knew it was a risk, but that's why I went with him so would have easier come back.

I actually wish what I knew now in that I would have gone for the Witson S160 style as it has the quad core processor 1.6ghz/2gb ram, but the one I did pick, partly by chance is probably the second best one I could have gotten for my needs (dual core 1.6ghz/1gb which is important for speed of unit), and I prefer the look of it too. I think if you tried again with a newer (and higher spec) model you would probably have better luck, although with yours being Bose I think you will have to fit some of the units in this post . Not a massive amount of work at all and the units seem cheap (albeit from the US, not sure what are best UK alternatives).
 

davidnormanuk

Registered User
I contacted Icebox and they weren't helpful at all apart from saying the stereo would need to be rewired to enable it to work with the Bose setup. I've bought another unit which appears to have the same Bose Hum. The humming noise appears to be coming from the front speakers only. Anyone able to help with this?
 

davidnormanuk

Registered User
Hi all,

After contacting a supplier of these stereos on ebay I was advised to use a ground loop isolator http://www.ebay.co.uk/itm/201153658407?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT as the factory alternator doesn't have a filter on it.

This works perfectly with no noise at all. I found I only needed to connect up 2 of the RCA's to get all the speakers working and not 4 as suggested.

Much much happier now and I have everything needed at the fraction of the cost of converting the original stereo to bluetooth.

This is the message I received from the chap on ebay.

New message from: thecoolbeansstorelimited (1,546 )
Good Morning David,

Sometimes with BOSE or other Audi amplified systems, you get some alternator whine or interference when you change the factory stereo to an after-market one. An after-market unit will always be more powerful than the stock unit so it requests more. The trouble is, the BOSE amplifier is not shielded so it causes humming, interference or engine whine through the speakers.

The best way to combat this is to ensure all exposed metal on the RCA connections are covered with tape so they cannot earth. Make sure the battery has more than 40% battery charge and all the cells are fine. Make sure everything that is being earthed is being earthed to the same place and the earth is solid.

You may also need to use some ground loop isolators and an interference suppressor to help eliminate this. These are very cheap products to help sort the issue out, much cheaper than replacing the BOSE amp.

From experience, a couple of ground loop isolators are always the fix.

Many Thanks,
Sean | Customer Service Team

The Cool Beans Store Limited
Opening Hours: Monday - Friday | 10am to 5pm
 
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