Mysterious static - Manville? PGT? Anybody?

[str8dwn]

I have this static that is heard in both left and right speakers regardless of whether my Cleansweep is using its Aux in or normal OEM radio input. In fact it doesn't even quit during the transition. Volums of the CS has no effect on this static either. It does it even with the OEM h/u off! I did read on another board someone else having the same issue when his was installed at the dealer. He never posted a fix though.

 

Before you go blaming the CS, JL replaced it with a completely new one when it was in for repairs (at my expense). With brand new one installed, nothing has changed. Same static. I thought it might be the OEM radio, but disconnecting the OEM input plug has no effect!

 

When I connect my iPod directly to my 300/4 via the same output RCAs used for the CS (bypassing it), the static goes away. I tested both sets of RCAs from the CS thinking one might be bad. Not the case it seems.

 

Suggestions to try to find the cuplrit? Could it be the ground for the CS? It currently comes from the H/U harness, but doesn't generate any engine noise. Should I move it to the same ground as the amps?

 

Update: I even moved the ground to the same spot as the amps and added the monster cable ground loop isolator i had lying around. Still does it!

 

I am really close to getting rid of this thing and getting a Navone LOC. I have spent way too much time and money for this type of performance. Ward, one of the tech guys at JL, was super nice, but he was not able to identify the problem.

 

Thanks in advance for the help.

 

[HighlineCA]

A few thoughts came to mind:

 

The RCA ends on the output

Connections on input side

Mounting location of CS

Unplug input side of CS, noise still there?

 

Give that a try.

 

Rich @ HCA

[str8dwn]

A few thoughts came to mind:

 

The RCA ends on the output

Connections on input side

Mounting location of CS

Unplug input side of CS, noise still there?

 

Rich @ HCA

 

Rich,

Thanks for the reply. When I unplug the input side of the CS (speaker and/or iPod) noise is still there. When I unplug the output RCAs from the CS and use a F-F coupler and connect the RCAs from the iPod input (bypassing the CS) directly to the amp, it goes away. The RCAs are new ZN7 3ft cables and work otherwise with the iPod. CS is mounted in the tirewell next to the amps. Ground is same location as amps.

 

You can see why I am baffled and at my wits end with this. Great ideas, keep them coming!

[CzarDestructo]

Just curious is this static or a hum? When you did this testing was the iPod running off the internal battery or hooked up with a car adapter? Reason I ask is almost all car adapters for small DC electronics like this use a switching power supply, which as you imagine, switch power on and off to get the desired voltage. Depending on the rate at which it flips the power on and off, cheap ones will induce a hum at its switching frequency through the ground (so it effects everything in your car, regardless). If you're hearing a hum through the speakers it could be courtesy of your iPods adapter.

 

Just a thought!

[str8dwn]

CzarDestructo,

That's a great thought. It's definitely not a hum, though I understand what you mean. It's just plain static in the background. It's very noticeable.

 

The static occurs with the iPod disconnected from the input on the CS or any inputs for that matter. Or even with the iPod disconnected from the docking cable.

 

Please keep suggestions coming!

 

To test, I think for $40 I'll order Navone's LOC and see if there is a difference. I'd still like the CS to work though since it was a pricey bugger and now I have two JL knobs in my shifter surround.

[msmith]

When you replaced the CS, did you replace the entire control knob assembly as well? If not, it could be a bad master volume control module. If you disconnect the master volume knob from the CS, does the noise stop? If it does, the fix is as simple as replacing the knob assy.

[msmith]

The only other thing I can think of is some sort of digital interference... where is your CS mounted?

[str8dwn]

Manville,

I did not replace the control assembly, but will when I return home. I did unplug it from the CS after turning the volume all the way down with the car off. Then it came on at a screamingly high volume after being silent for a few seconds. Didn't have time to listen for the static as I scrambled for the OEM knob.

 

The CS is mounted in the tire well with the amps and crossovers.

http://legacygt.com/forums/attachment.php?attachmentid=44994&d=1194126297

[msmith]

When you disconnect the Master volume cable from the CS, the CS will "remember" the last volume setting it received from the knob. So, turn down your OEM volume, turn up the CS master vol. and disconnect it. Then play the system using the OE Vol to see if the static persists. If it goes away, chances are that you need replace a defective knob assy.

 

I have my CS mounted in the same place as yours without any issues, so I doubt it's interference.

[str8dwn]

Manville you were right. The static goes away when I disconnect it and use the OEM volume as you indicated. I'll swap it out when I get back.

 

Only two odd things that seem to be coming into the system from CS are the ground loop (alternator whine) and high gain noise floor with no volume. None of this is present with the CS removed and the iPod is wired directly to the 300/4. The ground for the CS and my iPod adapter is at the same location as the amps (a JL Masterlug in the tire well).

 

I'd also like to thank you on behalf of all of LGT members for taking the time to answer our questions and be a part of the community.

[msmith]

Manville you were right. The static goes away when I disconnect it and use the OEM volume as you indicated. I'll swap it out when I get back.

 

Good to hear.

 

Only two odd things that seem to be coming into the system from CS are the ground loop (alternator whine)

 

Okay... some more questions

 

Is the alternator whine equal with the OEM and Aux Source?

Is the noise also present when the iPod is disconnected from power?

Did you twist the signal wires going to the spare tire well from the OEM radio?

Did you set the amp gains by ear or using the voltage meter technique?

If you disconnect the OEM input plug from the CS and put the CS in aux mode with a pair of shorted RCA's at the aux input, is the noise still there?

 

and high gain noise floor with no volume.

When using the CS vol. control or the OEM vol. control. If it's the latter, that is unavoidable, I'm afraid (and one of the reasons for the Master vol. knob). If it's the former, your gain structure or calibration might be off.

 

In my system, the iPod is powered and grounded at the cig. lighter plug inside the center console, the radio is grounded to its factory harness and the amps and CS are grounded to the master ground lug in the spare tire well. The signal wires are tightly twisted in pairs to avoid induced noise. My system is calibrated with the OEM radio flat and at Vol 25 and I have zero noise floor issues using the CS master vol. I have no alt. whine or excessive hiss.

 

We'll figure it out and get your system clean.

[str8dwn]

Update:

I almost completely gutted all wire from the car and re-ran it.

• JL 9-conductor twisted bundle for the OEM to Cleansweep connection and moved it opposite the power wire.
  
• Streetwires 4ga power on the opposite side
  
• Moved ground for CS to the cigarette lighter
  
• Swapped the CS knob assembly to the new one
  
• Left the iPod power connector and RCAs disconnected

All this....and....the static was still there.

 

I did finally get the static to go away by switching the signal input on the 300/4 amp from low to high. Of course now the amp will not put out the proper AC voltage, but volume seems decent enough in my late night, not pissing the wife off, low volume.

 

I am not sure if the engine noise is fixed as it's late. I'll test more tomorrow.

[msmith]

:confused:

 

Did you replace the CS control cable as well? If not, check the plugs carefully to see if any of the pins are bent, pushed in or missing on the cable.

[Wales Garage]

does this happen when the radio is on? this may be a shot in the dark but, is ther tint on the back window?

[str8dwn]

does this happen when the radio is on? this may be a shot in the dark but, is ther tint on the back window?

 

Wales,

Actually it does it when the radio is off and even when the source in the CS is switched to the Aux-in.

 

I have a few things to try tonight. We'll see.

[integroid]

str8dwn, sorry to hear of all the problems you are having with your system. I would still like to compare our systems when you get it together. Good Luck!

[str8dwn]

update:

Today I did the following:

• with CS fully connected and 300/4 with the input in the high position (no static), I switched it to low (static came back)
  
• made shorting plugs per Manville, disconnected RCAs on amp coming from CS (static stopped) and connected shorting plugs, a faint static sound with amp in low. High input, no static
  
• reconnected RCAs from CS to 300/4, put amp in low, disconnected control knob cable (still static), then disconnected OEM speaker input, (still static). Switched amp to high, no static
  
• Switched amp to low, changed source on CS to Aux in (static) and connected shorting plugs to aux in (still static)
  
• Switched CS back to OEM input, amp in low, switched from 2ch to 4ch input (amp is bridged - left is 1+2, right is 3+4), static only in left channel, switched to 2ch again, static in both channels (as was the case in all tests)

So then I:

• Completely disconnected the CS
  
• Connected the new Navone 4ch LOC
  
• Amp still in low position, faint static
  
• Switched to high, no static
  
• Re-adjusted the gains using the Sine wave voltage method
  
• No static, hiss and only a very minimal hint of engine noise

I still cannot figure out what is really causing the static. It may be the low input portion of the 300/4, but at this point, I have 9+ volt input from the Navone and it sounds great. I don't think it's the CS at this point since it is a brand new one. So for now the drama is finished. Thanks all for the help.

[msmith]

Based on your latest tests, it's clear to me that the problem is in the amplifier.

 

It's possible that it's just a scratchy potentiometer (sweep the gain and crossover pots through their full-range of motion several times to see if it fixes it). If not, you probably should send the amp in to us for service.

 

Sorry for all the issues,

 

Manville Smith

JL Audio, Inc.

[str8dwn]

I really am at my wits end with this. My system sounds terrible and I am not sure what to do. CS has been removed and sold CS on Ebay. Navone LOC has been put in its place and amps are in 'high' input. LOC did eliminate the static issue. Though engine noise is back.

 

Basically the issues are:

• 10w6v2 (in Stealthbox) sounds like it's blown, though it clearly has 2 ohm impedance and no air leaks (I did buy this from another member on the board) At moderate volume it 'pangs' making me think it's blown.
  
• Mounting of the box is pure crap. It makes noise over bumps and doesn't sit tightly, but the original bolt is as tight as I can get it.
  
• Gains on both JL amps were set using the AC voltage method, yet overall volume is still sub-par.
  
• Gains set with OEM vol at 25, yet when volume goes over ~15, it doesn't increase in volume. Even when turned all the way up to 25.
  
• Overall bass of the system sounds muddy and weak.

Should I take this into a shop and see if they can fix? Can anyone recommend a decent shop in Atlanta? I am ready to rip everything out and go back to the factory garbage.

[Colonel Lingus]

HiFi Buys still around? If so, not sure if they are any good still. There was a good one in Alpharetta

[str8dwn]

Yeah, I've thought about taking it to them. Over the phone they sounded more like they just install new stuff, but maybe they'd help. I had bad experience with Cartunes. They make you feel like if you're not Jermaine Dupri or Ludacris you're not worthy.

[PGT]

sorry I missed this...I'm not on as much as I used to be with the little one keeping me busy.

 

glad you could get things sorted. I had recurring FM issues....Manville got me another 500/1 which improved things, but even after getting the car retinted with non-metallic tint, the issue stayed. Open the hatch, works fine. Sometimes, noise is just a PITA and there's not much you can do.

[starhm]

another off the cuff...is the rear defroster on when there is an issue or is it constant?? i talked to someone with an 05 that talked about a problem with the radio and the defroster with reception. i am off base since you said the radio was not inputting, but it is the season for defroster. dont crucify me, just trying to help...i will go back and sit down now.

[integroid]

Hey Man, I know you probably looked at this but make sure your power and ground wires are NOT crossing over your RCA cables. I had a similar problem once...had the amp replaced under warranty...and still ahd noise. I put my old Alpine amp in and noise went away so I thought it was a bad amp. One day I moved the ground wire and the noise would get louder/quiter depending on how close it was to the input cables. I re-routed the grounds far away fromt he input cables and the noise went away. If that doesnt help, wait until Fry's has stiffening capactiors on sale for $29 and pick one up. They do wonders on giving good clean power to your amps.

 

Sadly, I am having some issues with my setup now too.