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Nashville TJ's Build Continued

Mike_H

But bird brains are
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Grand Rapids, MI, United States
I did a test using the high level input, and the same result - so no joy there either.

I also tried to swap the RCA cables again since the last time I did that was before I redid the ground connection. Same deal, no change. I even tried one channel at a time, swapping connections back and forth, to try to identify a bad channel. The static is the same no matter what I do.

On a whim I wired the + power connection directly to the battery to bypass the PDC. Same deal.

I've rechecked all my wiring to make sure I didn't cross something up, but I can't find anything.

Dammit.
Do you have a spare head unit to swap in and check? Kind of a PITA, because the connector probably wouldn't be the same...
 
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NashvilleTJ

NashvilleTJ

I miss the snow...
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Well, I took the time to go through and disconnect all the connections from the amp, and then slowly started reconnecting things double checking everything as I went. No change.

But then a little positive progress. I read through the Sony article that @JMT posted (Thanks Dude!), and one thing caught my eye. It said to set the volume to normal listening level with the music on pause, and if you hear static reduce the gain and increase the volume until you and find a balance between the two.

So I adjusted the gain knob (increased it, according to the markings) and sure enough the static was markedly reduced. Now in the documentation on the amp it said to set the gain to the voltage output on the head unit - 4 volts in my case. The documentation was clear: Do not set the gain by ear - set it to the proper voltage, which is what I had done.

The 3 gain adjustment dials are marked with voltage from 12 - .5 volts, clockwise, so I had originally set it at where 4 volts should have been according to the markings. I played with the gain a bit and found a setting which balanced the static and the volume. Funny, it wound up about where the 8 volt mark would be according to the markings - or at about where the 4 volt mark would be if the markings were reversed - which I'm thinking they are...

Still a little static, but a hell of a lot better than it was. I'll play with it a bit more tomorrow.
 

Trevlaw

Sketchy Machinist
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It's been a while since I've messed with this stuff, and any electrical advice from me is liable to get you in more trouble than you have already, but have you measured resistance from your ground point to your battery negative post yet?

Did you clean the paint down to bare metal real well, or just use a star washer to bite through the paint? I've been trying to sort out the grounds on my truck and decided to try just fastening connectors to bare metal with some NO-OX ID A conductive grease for the first try, no star washers or anything
 

JMT

The Jeep Guy
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Well, I took the time to go through and disconnect all the connections from the amp, and then slowly started reconnecting things double checking everything as I went. No change.

But then a little positive progress. I read through the Sony article that @JMT posted (Thanks Dude!), and one thing caught my eye. It said to set the volume to normal listening level with the music on pause, and if you hear static reduce the gain and increase the volume until you and find a balance between the two.

So I adjusted the gain knob (increased it, according to the markings) and sure enough the static was markedly reduced. Now in the documentation on the amp it said to set the gain to the voltage output on the head unit - 4 volts in my case. The documentation was clear: Do not set the gain by ear - set it to the proper voltage, which is what I had done.

The 3 gain adjustment dials are marked with voltage from 12 - .5 volts, clockwise, so I had originally set it at where 4 volts should have been according to the markings. I played with the gain a bit and found a setting which balanced the static and the volume. Funny, it wound up about where the 8 volt mark would be according to the markings - or at about where the 4 volt mark would be if the markings were reversed - which I'm thinking they are...

Still a little static, but a hell of a lot better than it was. I'll play with it a bit more tomorrow.
It is odd that the Voltage markings go down as you rotate the knob clockwise. That is counter to every dial we use. Maybe it was wrong and you’re really on 4V now as you suggest. I hope you can get the rest dialed out today.
 
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NashvilleTJ

NashvilleTJ

I miss the snow...
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It's been a while since I've messed with this stuff, and any electrical advice from me is liable to get you in more trouble than you have already, but have you measured resistance from your ground point to your battery negative post yet?

Did you clean the paint down to bare metal real well, or just use a star washer to bite through the paint? I've been trying to sort out the grounds on my truck and decided to try just fastening connectors to bare metal with some NO-OX ID A conductive grease for the first try, no star washers or anything
Yeah, I took my time on that ground. Ground down to bare metal, then used a 1/4” through bolt and nut tightened hard. Then the eyes go on the bolt, a flat washer, a split washer, and a second nut to hold it all together. 0 resistance to the battery. And now that both the amp and the head unit are grounded there, I don’t think I have a ground issue.
 
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NashvilleTJ

NashvilleTJ

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It is odd that the Voltage markings go down as you rotate the knob clockwise. That is counter to every dial we use. Maybe it was wrong and you’re really on 4V now as you suggest. I hope you can get the rest dialed out today.
I’m definitely thinking that’s the problem. When I turn the gain knob counterclockwise, toward the 12v mark, the volume slowly goes to 0. Kind of a dead giveaway…
 
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NashvilleTJ

NashvilleTJ

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Well, the gain adjustment did the trick. Adjusted it to about +8 volts according to the knob, +4 volts in the real world, and it pretty much took care of all of the static. The damned markings on the gain control definitely sent me on a wild goose chase for a couple of days. But, it's done. To my untrained ear, at this gain setting the sound is better as well.

Let this be a lesson to you kids - don't follow the directions!

I tucked the amp up into its final resting spot (remember that bracket I made like six months ago??? :rolleyes:), secured all the cables, and buttoned everything back up. Turned out to be a bigger project than planned, but I'm happy with the results.

Jeep - Stereo Amp 5 - 1-24-2022 (12).JPG


And now I get to go play with the new band saw.... :cool:
 
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NashvilleTJ

NashvilleTJ

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What are those hooks you used to hang your half doors? Can I get a close up of what’s going on back there?

I made those hooks many years ago out of cut-up u-bolts and some tubing.

IMG_0017.JPG


The soft uppers for those doors are in the bag against the wall. My windows go in the bag to the left when not on the rig.


IMG_0014.JPG


I also hang my full doors by the window frame on that rack, which is the reason it is padded.
 

Lonewolf

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Mar 4, 2019
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Pittsburg, CA
I made those hooks many years ago out of cut-up u-bolts and some tubing.

View attachment 305245

The soft uppers for those doors are in the bag against the wall. My windows go in the bag to the left when not on the rig.


View attachment 305243

I also hang my full doors by the window frame on that rack, which is the reason it is padded.
I really like that idea! I might have to copy it
 

rasband

Balls Deep
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I made those hooks many years ago out of cut-up u-bolts and some tubing.

View attachment 305245

The soft uppers for those doors are in the bag against the wall. My windows go in the bag to the left when not on the rig.


View attachment 305243

I also hang my full doors by the window frame on that rack, which is the reason it is padded.
How long have you hung the full doors? I was doing that for a bit but read that some people have seen stress cracks around the window frame and stopped (well, mostly since it's winter and they're on :p )