[TTSFan]

Hey all,

If you all been watching my sound posts you will know that today I had a JBL amp fitted back JBL slip system and it sounds AWESOME. Absolutely awesome. The ICE guys said the TT really has a nice "Housing" with all the doors closed to keep the sound going.

The only thing that is irritating the hell out of me is when the sound is off i.e. Muted there seems to be a very high pitched (its very vague but I know its there and its irritating me) sound almost like a tiny bit of feedback on a telephone. Its difficult to explain, I cant hear it when the music is one and the music is crystal clear but when its on mute I can hear it also if the radio is on and I start the car you can almost hear the starting of the car through the radio speakers?

Have the connected something incorrectly or have they forgot to put some sort of filter on the sound wires?

Thank you!

 

[markTT225]

Sounds like you have a ground loop problem. This is usually caused by a ground potential difference between your headunit and your amplifer. Or they might have routed the RCA cables along side power cables, causing an 'induced' pickup of electrical noise. A ground loop isolator in-line with your RCA cables going to the new amplifier might solve the problem. They cost about £10 so it's not going to break the bank . Alternatively, get them to re-position the grounding wire for the new amplifier to see if that helps.

 

[TTSFan]

Mark - as usual thank you very much for your help I REALLY appreciate it, I will get them to fix it tomorrow

 

[Janitor]

The only thing that is irritating the hell out of me is when the sound is off i.e. Muted there seems to be a very high pitched (its very vague but I know its there and its irritating me) sound

Tinnitus..?

[smiley=dude.gif]

:wink:

 

[TTSFan]

A ground loop isolator in-line with your RCA cables going to the new amplifier might solve the problem.

So he fitted the GLI today and it made the noise even worse :? I could hardly hear it but I knew it was there after he fitted the GLI I drove out and I could hear it as I revved the car

He said no problem I should disconnect it and he is going to order the grandaddy of GLI's for me and should be here on Monday.

He said he has had the same problem on the 2007 - 2008 GTI's but they worse when you turn the lights on you can actually hear it to....

Now I am confuzzzzzzed :? :? :? :?

 

[markTT225]

A ground loop isolator in-line with your RCA cables going to the new amplifier might solve the problem.

So he fitted the GLI today and it made the noise even worse :? I could hardly hear it but I knew it was there after he fitted the GLI I drove out and I could hear it as I revved the car

He said no problem I should disconnect it and he is going to order the grandaddy of GLI's for me and should be here on Monday.

He said he has had the same problem on the 2007 - 2008 GTI's but they worse when you turn the lights on you can actually hear it to....

Now I am confuzzzzzzed :? :? :? :?

[smiley=huh2.gif] If the GLI doesn't work, I can only guess that the RCA feeds are picking up noise from being run too close to power cables then. What route has he chosen for these?

 

[TTSFan]

So SA cars are right hand drive (I assume UK cars are the same ) he ran the RCA's from the left hand side. He said he made sure he ran the RCA's on the opposite side of the power cables. It was the first thing I asked him

I am so happy with the JBL back speakers and the JBL AMP but this sound interference is driving me nuts.

They going to fit the "grandaddy" of GLI's tomorrow so lets see if it helps I will keep everyone posted. He did say he has the same problems with the new GTI's to. He says you even hear a sound in the speakers when you turn on the lights :S.

If you think of anything else let me know

 

[markTT225]

So SA cars are right hand drive (I assume UK cars are the same ) he ran the RCA's from the left hand side. He said he made sure he ran the RCA's on the opposite side of the power cables. It was the first thing I asked him

I am so happy with the JBL back speakers and the JBL AMP but this sound interference is driving me nuts.

They going to fit the "grandaddy" of GLI's tomorrow so lets see if it helps I will keep everyone posted. He did say he has the same problems with the new GTI's to. He says you even hear a sound in the speakers when you turn on the lights :S.

If you think of anything else let me know

Lets's hope the Grandaddy GLI does the job then. I didn't think there was much to choose between GLI's - they all basically do the same job by coupling the audio through transformers thereby stripping the 'DC' component off the signal. Maybe some are better than others, using higher quality ferrite cores etc.

Keep us posted mate :wink:

 

[TTSFan]

Right so they fitted the Audio Vox GLI and it removed 90% of the humming sound. I was really after 100% but I am not sure if you can get 100%.... (or can you?), the next thing the ICE guys said is instead of using a High \ Low converter they could do Highlevels but they haven't used that in like 10 years. The High \ Low converter is completely isolated away from any electrics

Mark your thoughts?

 

[markTT225]

Right so they fitted the Audio Vox GLI and it removed 90% of the humming sound. I was really after 100% but I am not sure if you can get 100%.... (or can you?), the next thing the ICE guys said is instead of using a High \ Low converter they could do Highlevels but they haven't used that in like 10 years. The High \ Low converter is completely isolated away from any electrics

Mark your thoughts?

So, let me see if I understand your set-up. You are converting the speaker level (high) to RCA Line-level (low) and feeding this to the amp RCA inputs? Wouldn't it have been better to simply use the line-outs straight from the headunit? (therefore no adapters required) :? Adding as few processing components in the chain as possible is always a good idea for the best sound quality.

 

[TTSFan]

So, let me see if I understand your set-up. You are converting the speaker level (high) to RCA Line-level (low) and feeding this to the amp RCA inputs? Wouldn't it have been better to simply use the line-outs straight from the headunit? (therefore no adapters required) Confused Adding as few processing components in the chain as possible is always a good idea for the best sound quality.

Ok so stick with me here (I am not technical) - Is this what they refer to as using High Levels?

They said there were no RCA outputs on the back of the concert thats why they had to use a High to Low converter..... and you right they taking the HIGH's and converting them to Lows on the RCA's

 

[markTT225]

So, let me see if I understand your set-up. You are converting the speaker level (high) to RCA Line-level (low) and feeding this to the amp RCA inputs? Wouldn't it have been better to simply use the line-outs straight from the headunit? (therefore no adapters required) Confused Adding as few processing components in the chain as possible is always a good idea for the best sound quality.

Ok so stick with me here (I am not technical) - Is this what they refer to as using High Levels?

They said there were no RCA outputs on the back of the concert thats why they had to use a High to Low converter..... and you right they taking the HIGH's and converting them to Lows on the RCA's

Yes, 'high level' refers to the signal coming from the headunit that has amplification added to it (from the internal amplifier).

I would be very surprised if there was no line-out available from your headunit. Would it be possible for you to post a picture of your headunit - I need to see the sticker on the top of the unit (pin-out diagram) and the rear connections. You will need to remove the headunit from the car for this obviously :wink: )

 

[TTSFan]

Ok let me try get the removal key's..... it is a concert I just don't want to go back to the ICE guys as they quite far from me.

 

[markTT225]

I'm 99.9% sure that you will have line-out available if you have the quadlock connector on the back. I suspect that the ICE guys are being lazy with the wiring, just taking the feeds off the front speakers. What i think you will need is a line-out adaptor like this:

http://cgi.ebay.co.uk/Line-OUT-AUX-IN-a ... dZViewItem

How have they wired the front speakers - are they wired direct off the headunit, or are they running off a separate amp?

 

[TTSFan]

I'm 99.9% sure that you will have line-out available if you have the quadlock connector on the back. I suspect that the ICE guys are being lazy with the wiring, just taking the feeds off the front speakers. What i think you will need is a line-out adaptor like this:

http://cgi.ebay.co.uk/Line-OUT-AUX-IN-a ... dZViewItem

How have they wired the front speakers - are they wired direct off the headunit, or are they running off a separate amp?

Remember the history (with my one month old car) with my car. I ordered the Concert radio and they made a mistake and it came with the chorus. They then replaced the head units only. The Chorus only comes with a speaker (not sure if its a mid or a driver...) at the bottom of the door and the little tweaters by the pillar (by the front aircon ducts by the doors.

Nothing else no AMP nothing. Thats why they added the JBL AMP into the car.

Now I was there when the swapped out the head units and I remember the TT with the concert had a connector that plugged into the back. it was a square and had a WHITE and GREEN plug in this square bracket. The Chorus had the same square bracket and a WHITE and BROWN plug in the bracket.

I remember when they plugged the Chrous into the TT that had the concert all the speakers where playing no problem. Obviously mine didn't have speakers in so only the front and tweeters played.

I am going to phone them now and ask them what they have done I wasnt there and you know I am not technical Mark you awesome thanks for ALL the help so far!!!!!!! Do you suspect the noise is coming from the High to low converter?

 

[TTSFan]

Ok so just got off the phone with them, they said they use to use those connectors but found with a separate (external) AMP when you switched the car on (i.e. power was supplied) there was a popping sound on the speakers so they stopped using them.

What they did is the harness that goes into the radio they tapped into those - don't know what terminology that is.....

The fronts are connected to the AMP and so are the new backs. The AMP is a JBL GT Series

 

[TTSFan]

http://www.jbl.com/car/products/pro...age=ENG&Country=US&Region=USA&cat=AMP&ser=CSS

Thats a link to the JBL Amp

 

[markTT225]

I'm 99.9% sure that you will have line-out available if you have the quadlock connector on the back. I suspect that the ICE guys are being lazy with the wiring, just taking the feeds off the front speakers. What i think you will need is a line-out adaptor like this:

http://cgi.ebay.co.uk/Line-OUT-AUX-IN-a ... dZViewItem

How have they wired the front speakers - are they wired direct off the headunit, or are they running off a separate amp?

Remember the history (with my one month old car) with my car. I ordered the Concert radio and they made a mistake and it came with the chorus. They then replaced the head units only. The Chorus only comes with a speaker (not sure if its a mid or a driver...) at the bottom of the door and the little tweaters by the pillar (by the front aircon ducts by the doors.

Nothing else no AMP nothing. Thats why they added the JBL AMP into the car.

Now I was there when the swapped out the head units and I remember the TT with the concert had a connector that plugged into the back. it was a square and had a WHITE and GREEN plug in this square bracket. The Chorus had the same square bracket and a WHITE and BROWN plug in the bracket.

I remember when they plugged the Chrous into the TT that had the concert all the speakers where playing no problem. Obviously mine didn't have speakers in so only the front and tweeters played.

I am going to phone them now and ask them what they have done I wasnt there and you know I am not technical Mark you awesome thanks for ALL the help so far!!!!!!! Do you suspect the noise is coming from the High to low converter?

Using the High to Low converter probably isn't helping matters, but is probably not the source of the noise. The fact that you are 'attenuating' (lowering) a large signal, and then boosting it again (with your new amp) is going to add noise into the system - as you are then amplifying noise as well as signal after this point.

 

[markTT225]

http://www.jbl.com/car/products/pro...age=ENG&Country=US&Region=USA&cat=AMP&ser=CSS

Thats a link to the JBL Amp

If they absolutley HAVE to use the 'high' level outputs from the headunit, why have they used the high -low converter? That amplifier has input level adjustments on it (look at the PDF file image and zoom in).

 

[TTSFan]

If they absolutley HAVE to use the 'high' level outputs from the headunit, why have they used the high -low converter? That amplifier has input level adjustments on it (look at the PDF file image and zoom in).

Ok so after the Audio Vox GLI install and about 85 - 90% of the noise gone - I still can't live with the buzzz, what makes it worse is I can hear a increase for about 4 seconds when I switch the Xenons on.....

He has guaranteed me the following:

1. The RCA's are installed on the opposite end of the car than the power cables are run.
2. They say they tapped into the the wire harness at the back as the Audi Concert had not RCA's outputs - I don't know why they would use a High to Low converter then (Not technical - Any idea's Mark?)
3. They said because of the radio setup they couldn't get the Front \ Back to fade they can get left right but no front back (anyone know why?)

So -- what options I am left with (please add some {if its valuable input})

1. Get the RCA addons as per Mark's post -- thanks once again -- will this really help or are we trying trial and error?
2. They are going to try and move the High to Low converter around to try and get it away from ANY electronics (even though they have already guaranteed me that its no where close to electronics.
3. They currently have a GLI fitted to the front speaker inputs only, they going to fit one to the back speakers as well (By the amp).

Any questions I should be asking them tomorrow when I am standing there watching them doing this ... I want to make sure they do this.

This is so frustrating when you know the sound is there it just gets to you EVERY time....