Hissing Noise With New Hu ! Please Help !

[Dego]

I just installed this unbranded system in my 2002 Lexus IS200 S yesterday, I couldn't really afford anything top end. Check out this link for details click here Anyway the problem is that I am getting a hissing noise in the speakers, like interference or something. I used the passion automotive iso adaptor cable click here and a modified autoleads fascia kit click here to fit the HU. The noise is present during DVD video and music playback, during radio, SD/USB, in fact it is present during all sound media applications. I am still using standard speakers. As the fascia kit is plastic the HU chassis is isolated but the HU is still grounded through the ISO lead. The noise is more noticable at low volumes. I fitted this system because of CD errors on my OEM HU, but there was never any hissing present with the old HU. Could this be rectified, or is it a cheap HU problem? Please help

[aaronabbott]

sounds like interferance somewhere have you got a sub and amp anywhere,whats the head unit like im watching one on eBay

[redz_UK]

i would guess that its a poor amplification stage in the HU.. you can get this on cheap units.. i would suggest trying it with an ampflifier if you can and let us all know how you get on.. it certainly is v cheap for what it does!!

[Dego]

i would guess that its a poor amplification stage in the HU.. you can get this on cheap units.. i would suggest trying it with an ampflifier if you can and let us all know how you get on.. it certainly is v cheap for what it does!!

Thanks for the replies so far. The HU is ok for its price. Picture quality is nothing spectacular but it has plenty of features which I hope to make use of in the future. The built in mic for the Bluetooth kit could do with a bit higher gain. Has anyone else out there got one of these HU's and have they encountered any problems? Also the point of buying this was it's price, if I need to get a an amp to improve its sound then it kind of defeats the purpose. Could it be an earthing problem or some other wiring problem? A mate has told me you get what you pay for, but I hope it can be sorted.

[Dego]

I forgot to say that the only change I made was the HU. There are no amps or subs etc.

[sparkystav]

I sometimes have the hissing with the same unit, but not got round to diuagnosing it yet.

The Bluetooth feature i dont like as well as the mic, as you say is terrible.

Stav

[redz_UK]

if there are two units with the same problem then i would say it is down to the quality of the output stage..

an amp running of the rca outputs may help.. you could pick up a decent amp for about £100..

amp

Stav how have you got yours wired up??

[Dego]

if there are two units with the same problem then i would say it is down to the quality of the output stage..

an amp running of the rca outputs may help.. you could pick up a decent amp for about £100..

amp

Stav how have you got yours wired up??

It would seem to be no coincidence. I was reading that some people are having problems running the standard speakers on aftermarket amps. Whats the best approach? Lexus wiring diagrams would be a help if anyone out there could help?

Did you use the same iso lead as me Stav? I was thinking of rewiring a bit to allow the DVD video to play whilst moving. Time to get the multimeter out!!!

[redz_UK]

if there are two units with the same problem then i would say it is down to the quality of the output stage..

an amp running of the rca outputs may help.. you could pick up a decent amp for about £100..

amp

Stav how have you got yours wired up??

It would seem to be no coincidence. I was reading that some people are having problems running the standard speakers on aftermarket amps. Whats the best approach? Lexus wiring diagrams would be a help if anyone out there could help?

Did you use the same iso lead as me Stav? I was thinking of rewiring a bit to allow the DVD video to play whilst moving. Time to get the multimeter out!!!

to get the dvd to plat whilst moving all you need to do is identify the lead that connects to the handbrake and ground it..

fronts will work ok with standard speakers, rears are actually 2 x speakers on each side so you will have to rewire them to 3 ohms (not ideal) or put new ones in..

[Dego]

I contacted the seller about the noise and got this short vague reply:

"we have not heard of hissing noice - if possible please recheck the wiring to the speakers and make sure they are connected correctly and securely."

Needless to say this was no help whatsoever. So I remain clueless. Would an ICE shop be likely to hook up an amp to test the HU on the understanding that if it eliminated the hiss I would be buying the amp? Surely they would have opened box products lying about? I can't justify spending money on an amp that might not fix the problem.

[sparkystav]

I have it running soley throught the RCA,s and not i dont use the ISO lead.

Stav

[redz_UK]

if stav has it running off rca leads and an amp then it's just how the unit is. adding an amp wont help by the looks of it,

u can try taking it to a car hifi shop but doubt they will be able to help mate..

sorry...

[Dego]

to get the dvd to plat whilst moving all you need to do is identify the lead that connects to the handbrake and ground it..

fronts will work ok with standard speakers, rears are actually 2 x speakers on each side so you will have to rewire them to 3 ohms (not ideal) or put new ones in..

I successfully grounded the proper wire and it plays all the time now, but I was wondering would that safety feature ever have to be demonstrated as working to either the police or at MOT tests?

[aaronabbott]

when i had my dvd player in on the mot nobody said anything,not to sure about the police though.to be honest its to low down to see from behind anyway and you could always press the button to switch it off anyway,how did you get on with the hissing anyway cos i was looking at the same hu on eBay?

[Dego]

when i had my dvd player in on the mot nobody said anything,not to sure about the police though.to be honest its to low down to see from behind anyway and you could always press the button to switch it off anyway,how did you get on with the hissing anyway cos i was looking at the same hu on ebay?

I've nearly grown used to it. I'm a bit of a perfectionist and would prefer to fix it if possible but its not the end of the world. I'll keep trying to find a solution for a while yet. I had wired in a switch to enable the wire to be connected one way as normal, and the other way to chasis ground, but for some reason it didn't work. Couldn't figure it out so it's now permanently grounded. Has anyone else made such a switch setup?

[redz_UK]

when i had my dvd player in on the mot nobody said anything,not to sure about the police though.to be honest its to low down to see from behind anyway and you could always press the button to switch it off anyway,how did you get on with the hissing anyway cos i was looking at the same hu on ebay?

I've nearly grown used to it. I'm a bit of a perfectionist and would prefer to fix it if possible but its not the end of the world. I'll keep trying to find a solution for a while yet. I had wired in a switch to enable the wire to be connected one way as normal, and the other way to chasis ground, but for some reason it didn't work. Couldn't figure it out so it's now permanently grounded. Has anyone else made such a switch setup?

just put a normal swith on the lead that you have grounded if you really want to do this...