Hi Guys......audio isn't really my thing but I 've a problem and it's driving me nuts....... I had, in the car a sony head unit, all channels feeding out on rca jacks to an amp in the boot.....then to the speakers :hyper: this worked brilliantly no noise and good sound reproduction. The wife has bought me a new head unit for christmas......usb in, cd player and memory card etc.....seems a good piece of kit TBH.....but no rca outputs, so went to local car audio shop and got some pre amp rca converters as advised by them, installed into the car and followed all directions to the letter. when the engine is running every dog in town can hear my motor cause I've now got a very high pitched whistle( not present with engine off) so I fitted an inductive filter(coil) to the acc on the head unit....made things a little better but not completely gone. Was in Warrinton today so called in at Halfrauds...guy was very helpful but said there units were expensive but nip to Muplins and get the same thing for a few quid less.....I liked this guy :rofl:

got the filters from muplins and fitted them( just before the amp) but still whistling (Muplins part no vw43w ... ground loop isolator). will try at the head unit later in the week

 

 

 

 

HELP THIS IS DRIVING ME NUTS.......If I can't sort it then the sonys going back in

 

 

 

 

Pete :(

right, moved the filters to the rca converters at the head unit......no difference....

 

 

c'mon guys really struggling here.....audio not my strong point, tbh I'm partially deaf and can't hear it unless i'm on top of the speakers...any speaker that is. But the wife, son and daughter are ok, they can hear it then give me grief to turn it off.

 

 

 

Pete

no real expert on this but i have a vdo head unit and i thought there was no amp out on it turns out that it was a seperate cable that plugged into the back of the head unit worth a try. on a older car radio i had to use a converter no probs was a top end one though.does your whistle gain in pitch when the engine revs are raised ?

sounds like a ground loop problem or some type of feed back why not try running a speaker cable to the rear of the car and fit rca converters there might find that because they are in same area as headunit they might be interfering with each other

you could try , balanced cables make sure they are o.f.c and you can also clip ceramic sleeves over the front and rear ends of the cables about 2 inches in. rf suppresion clips, they put them on pc screen cables they are the big thick round things on the cables, you can buy them at maplins and clip them around the cables.

 

the cable is acting as a frequency pick up, i used to have this all the time in my studio, on a good day i could pick up the local taxi firms radio on my speakers clearly!!

 

changed all my cables to top of line vanne damme cables all balanced and o.f.c i also put some ceramic clips over them and all was clear, not even a line level hiss anywhere.

if the whistle increases in pitch with the engine revs its more than likely to be interfierence from the alternator

Its definately a ground loop problem...what u'll prob find is either there is insufficent earthing in the engine bay or your alternator shielding is giving up. What it means is that any high electrical chargin or current ie alternator will send some of its earth current through the headunit or amp power cabling.

 

Pete if u want one i got a ground loop isolator here you can have.And it s a proper hefty one so it'll sort it, plus i can check ur wiring.

 

Oh and by the way i'll be moving to winsford in a month!! Hahahaha you can't escape now!!!

 

Giz a call if u want mate i'll talk you through it!

 

Rich :hyper:

Thanks for the suggestions guys, I'll have a look into everything over the next day or two......If I get completly hacked off then the sony's goin back in and I'll source one of those usb/radio transmitter thingies that plugs into the lighter socket, Rich thanks for the offer, the units I got from Muplins are ground loop Isolators....so they said :confused: . By the way I got my conzult but I'm tied up for the next few weeks unless you can get it up here or wait until you live up here.......give me time to learn a bit more.....so far I've worked out I need a left bank O2 sensor as It doesn't cycle above 2000 revs.....still not had time to sort out my own cars cutting out prob.

 

 

 

 

 

Pete :(