Constant buzz


Thunderturkey96

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May 2, 2020
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So I just got done doing a bi- amp set up in my 95 ford thunderbird. I have a 80prs radio, a kenwood X-542 amp on Audison Voce components for mids and highs. I’m using the crossovers in-line on tweeters, and I have a crescendo bc2000d @ 2 ohm on a Rockford T1 sub. The problem I’m having is I have a constant high pitch noise that only comes through the tweeters I cannot figure out. I had coaxial speakers in place of the mid woofer and even those tweeters where doing it since then have put in the Audison mid which has no tweeter obviously. So far I have ran new rca’s made no difference, turned gains way down to see if maybe that was the culprit made no difference, tried grounding rca’s on back of radio, made new hum so promptly removed it went back to how it was. The weird thing is it’s more noticeable when the car is cold after the system has been on for awhile is gets a lot quieter till it’s almost inaudible but still there. The noise also doesn’t change with rpm and even makes it when the engine is off Completely. I also tried a different radio I had lying around and that also made no difference as well, and besides this issue the system sounds amazing..... Any ideas???
 

Lasherž

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Apr 27, 2020
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So I just got done doing a bi- amp set up in my 95 ford thunderbird. I have a 80prs radio, a kenwood X-542 amp on Audison Voce components for mids and highs. I’m using the crossovers in-line on tweeters, and I have a crescendo bc2000d @ 2 ohm on a Rockford T1 sub. The problem I’m having is I have a constant high pitch noise that only comes through the tweeters I cannot figure out. I had coaxial speakers in place of the mid woofer and even those tweeters where doing it since then have put in the Audison mid which has no tweeter obviously. So far I have ran new rca’s made no difference, turned gains way down to see if maybe that was the culprit made no difference, tried grounding rca’s on back of radio, made new hum so promptly removed it went back to how it was. The weird thing is it’s more noticeable when the car is cold after the system has been on for awhile is gets a lot quieter till it’s almost inaudible but still there. The noise also doesn’t change with rpm and even makes it when the engine is off Completely. I also tried a different radio I had lying around and that also made no difference as well, and besides this issue the system sounds amazing..... Any ideas???
It's feedback from the charging system and the amp's current draw. Did you run your power cables on the same side as the RCA? That's a no no unless you have a very strong signal and good cables. It gets louder when the system is cold because more power is drawn from the alternator when it's cold (more efficient) and you also just started the car, so the battery is charging from the starter load. Your 80PRS actually has a pretty strong signal surprisingly. When it gets to the amp is there slack coiled up on either the b+ cable or the RCAs? Coils make it worse
 

Thunderturkey96

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May 2, 2020
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So even with the car off, try changing out the voice amp. It may be a bad capacitor in it.
Yeah no engine running with just having accessories on it still does it, my power and rca’s are ran on opposite sides of the car. The amp is quite old but didn’t have any issues with it the last time it was in this car on my old setup. But it sat around for almost a year before I got around to working on my current setup.
 

Lasherž

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Apr 27, 2020
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Yeah no engine running with just having accessories on it still does it, my power and rca’s are ran on opposite sides of the car. The amp is quite old but didn’t have any issues with it the last time it was in this car on my old setup. But it sat around for almost a year before I got around to working on my current setup.
In that case maybe it's worth trying out the head unit's outputs to see if it goes away.
 

Thunderturkey96

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So I got home got some Y splitters and a AUX jack to headphone jack adapter plugged it all in Directly at the amp and the buzz is gone! But I already tried different RCA’s that I just plugged in at the amp and into to the back of the radio ran them over top of the carpet quick and it made the same buzzing so the amp is good, the rca’s and crossovers are good, so I’m lead back to the head unit again, but I tried a random JVC unit in my 80prs place and it still made the same buzz with that as well. So is it a issue with the power leads to the radio at this point????
 

audiobaun

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Check your amplifiers grounds. Make sure clean and solid ground points and add anther ground wire at the HU see if that may help.
 
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blazian87

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Mar 12, 2007
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So I got home got some Y splitters and a AUX jack to headphone jack adapter plugged it all in Directly at the amp and the buzz is gone! But I already tried different RCA’s that I just plugged in at the amp and into to the back of the radio ran them over top of the carpet quick and it made the same buzzing so the amp is good, the rca’s and crossovers are good, so I’m lead back to the head unit again, but I tried a random JVC unit in my 80prs place and it still made the same buzz with that as well. So is it a issue with the power leads to the radio at this point????
Are you using twisted pair RCA's or shielded rca's? The reason why I ask is because there's a thing called differential and single ended inputs that are built into amps. Just by using the correct type of wire, this can possibly solve your problem. It may or may not work but I think it's worth testing the ohms with a DMM and if it turns out to be single ended (<1000 ohms), I would go ahead and try getting ahold of some good shielded rca's and see if it actually fixes the problem. This would be my suggestion if all else fails.
 
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1aespinoza

Junior Member
May 22, 2013
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Pharr, Texas
Try grounding the radio chassis. I really can think of nothing else since other radios do the same thing, and also random rca cables. Maybe blazian87 is right about certain rca cables. Audiophile equipment is so clean that it picks up even the slightest noise. I had a similar problem on a Pioneer z2. I gave up and used only one set of rcas to the voice amp and from there to bass amp. Noise gone. Good luck.
 
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Thunderturkey96

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May 2, 2020
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Check your amplifiers grounds. Make sure clean and solid ground points and add anther ground wire at the HU see if that may help.
Are you using twisted pair RCA's or shielded rca's? The reason why I ask is because there's a thing called differential and single ended inputs that are built into amps. Just by using the correct type of wire, this can possibly solve your problem. It may or may not work but I think it's worth testing the ohms with a DMM and if it turns out to be single ended (<1000 ohms), I would go ahead and try getting ahold of some good shielded rca's and see if it actually fixes the problem. This would be my suggestion if all else fails.
I am using Rockford fosgate twisted pair rca’s
 

audiobaun

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Most wiring harnesses have a weak ground wire plugged in. Sometimes Ive had to add a single ground wire along with splicing the ground wire on the harness and attach to a solid grounding point behind or under the dash of which helped out in the past on a couple HUs ive installed.
 
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audiobaun

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14ga or 12 ga wire works just fine.. You can use 16 ga speaker wire doubled up twisted together as one wire if thats all you have that works just as well.
 

Thunderturkey96

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14ga or 12 ga wire works just fine.. You can use 16 ga speaker wire doubled up twisted together as one wire if thats all you have that works just as well.
14ga or 12 ga wire works just fine.. You can use 16 ga speaker wire doubled up twisted together as one wire if thats all you have that works just as well.
So my buddy at work says that I should run both power and ground for the radio directly to the battery with 12 ga any thoughts on this/ would it be a good idea to do so in my case???? Or would running a 12 ga ground only be just as good?
 

audiobaun

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So my buddy at work says that I should run both power and ground for the radio directly to the battery with 12 ga any thoughts on this/ would it be a good idea to do so in my case???? Or would running a 12 ga ground only be just as good?
I wouldnt run either wiring to battery.Power wire will be on Constant and run your battery down.Running a ground wire all the way to the battery is a waste of time and wiring when you can simply run approx 2-4 ft of 14-12 ga single wire to a SOLID GROUND to Bare Metal with a Screw and Ring terminal and maybe a washer= approx $2-5 bucks. I would recommend not taking any advice from your Buddy at work on this or you"ll end up stranded needing a jump start to get somewhere
 

Lasherž

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Apr 27, 2020
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So my buddy at work says that I should run both power and ground for the radio directly to the battery with 12 ga any thoughts on this/ would it be a good idea to do so in my case???? Or would running a 12 ga ground only be just as good?
Absolutely not. The ground wire is shorter than the power wire for a big reason, and that's safety. What's the point of having a fuse if the longest length of wire generating heat is an unfused ground? The ground cable should be short. Use the chassis, it's an amazing ground without needing a terminal right to the battery (electrically it basically is, vdrop on ground is minimal). You won't necessarily drain your battery because the ignition cable is, I assume, still going to be connected in line with your key wiring, but it's proper to just screw the terminal into solid metal somewhere behind the radio. Some radios provide a black ground right from the harness and I believe that goes back to the fuse box to ground, which is just fine too, why not both?

audiobaun's suggestion of splicing the ground wire from the harness to a grounded chassis terminal is a great idea if that's all you have, a lot of radios come with a ground terminal point already but there's no harm in adding one if you think it's a grounding issue (which are quite common).
 

Thunderturkey96

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May 2, 2020
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Absolutely not. The ground wire is shorter than the power wire for a big reason, and that's safety. What's the point of having a fuse if the longest length of wire generating heat is an unfused ground? The ground cable should be short. Use the chassis, it's an amazing ground without needing a terminal right to the battery (electrically it basically is, vdrop on ground is minimal). You won't necessarily drain your battery because the ignition cable is, I assume, still going to be connected in line with your key wiring, but it's proper to just screw the terminal into solid metal somewhere behind the radio. Some radios provide a black ground right from the harness and I believe that goes back to the fuse box to ground, which is just fine too, why not both?

audiobaun's suggestion of splicing the ground wire from the harness to a grounded chassis terminal is a great idea if that's all you have, a lot of radios come with a ground terminal point already but there's no harm in adding one if you think it's a grounding issue (which are quite common).
Right
I wouldnt run either wiring to battery.Power wire will be on Constant and run your battery down.Running a ground wire all the way to the battery is a waste of time and wiring when you can simply run approx 2-4 ft of 14-12 ga single wire to a SOLID GROUND to Bare Metal with a Screw and Ring terminal and maybe a washer= approx $2-5 bucks. I would recommend not taking any advice from your Buddy at work on this or you"ll end up stranded needing a jump start to get somewhere
Right on I thought it would be a waist of time but figured I would at least ask and see if anyone else has tried it with any success
 

Thunderturkey96

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May 2, 2020
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So yesterday I have removed and cleaned all grounds to shiny bare metal, added a new 12ga ground to the existing ground in the dash for the radio Which is the only ground I found that metered on the high side of things, used my multi meter to test my rca’s they are all good, Tested all my grounds with said multimeter, and everything is good there, I put a different cheapo pioneer in it, and nothing has changed and the sound still is there. If I hook up my phone to the rca’s in dash with the Y splitters, barrel connectors, and the headphone to rca adapter there is no buzz... I literally feel like I’m about to rip my hair out over this. I dont think it’s a grounding issue anymore as I tested all grounds for the audio system and everything meters out fine. What should I do next to try to resolve my issue. If I Where to have a bad capacitor in the amp is there anyway to test for that? And would there be a logical explanation of why it would go away when I play the system off of my phone?
 

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