Home » Public Forums » GMCnet » [GMCnet] Whiny Stereo
| [GMCnet] Whiny Stereo [message #323322] |
Mon, 04 September 2017 16:07  |
kelvin
Messages: 608
Registered: February 2004
Location: Eugene, OR
Karma: 0
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Stereo issues. Or alternator.
I have a "whine" thru my stereo speakers. Doesn't matter if I'm playing
a radio station or Bluetooth thru the phone. I'm going to guess a CD
will do it, too, but just realized I haven't tried that.
My Stereo Guy suggested there was a problem with the stereo itself but I
just happen to have the same unit in my car so I swapped it. No problem
in my car but the same whine in the GMC. He gave me a "filter" to place
on the 12V wire but didn't seem to think that would do anything. He was
right.
Sometimes louder than others and sometimes it even goes away. It does
seem to change with engine speed.
Any ideas? I can install and wire sound systems but don't really
understand all the ins and outs.
Thanks,
Kelvin
'73 23' in Eugene, OR
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| Re: [GMCnet] Whiny Stereo [message #323323 is a reply to message #323322] |
Mon, 04 September 2017 16:15  |
sgltrac
Messages: 2797
Registered: April 2011
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it could be coming through your ground circuit. Try a different ground
path. If that doesn't work check your speaker outputs for contact with
grounded surfaces.
Sully
77 eleganza 2
Bellevue
On Mon, Sep 4, 2017 at 2:08 PM Kelvin Dietz wrote:
> Stereo issues. Or alternator.
>
> I have a "whine" thru my stereo speakers. Doesn't matter if I'm playing
> a radio station or Bluetooth thru the phone. I'm going to guess a CD
> will do it, too, but just realized I haven't tried that.
>
> My Stereo Guy suggested there was a problem with the stereo itself but I
> just happen to have the same unit in my car so I swapped it. No problem
> in my car but the same whine in the GMC. He gave me a "filter" to place
> on the 12V wire but didn't seem to think that would do anything. He was
> right.
>
> Sometimes louder than others and sometimes it even goes away. It does
> seem to change with engine speed.
>
> Any ideas? I can install and wire sound systems but don't really
> understand all the ins and outs.
>
> Thanks,
> Kelvin
> '73 23' in Eugene, OR
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] Whiny Stereo [message #323324 is a reply to message #323322] |
Mon, 04 September 2017 16:22 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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kelvin wrote on Mon, 04 September 2017 14:07Stereo issues. Or alternator.
I have a "whine" thru my stereo speakers. Doesn't matter if I'm playing
a radio station or Bluetooth thru the phone. I'm going to guess a CD
will do it, too, but just realized I haven't tried that.
My Stereo Guy suggested there was a problem with the stereo itself but I
just happen to have the same unit in my car so I swapped it. No problem
in my car but the same whine in the GMC. He gave me a "filter" to place
on the 12V wire but didn't seem to think that would do anything. He was
right.
Sometimes louder than others and sometimes it even goes away. It does
seem to change with engine speed.
Any ideas? I can install and wire sound systems but don't really
understand all the ins and outs.
Thanks,
Kelvin
'73 23' in Eugene, OR
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Is this something new?
I noticed a whine coming from my stereo for a hundred miles or so just before my alternator conked out on the way to Moab a few years ago.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
[Updated on: Mon, 04 September 2017 16:40] Report message to a moderator |
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| Re: [GMCnet] Whiny Stereo [message #323326 is a reply to message #323324] |
Mon, 04 September 2017 16:26 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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Carl,
I remember issues with engine noise in aftermarket stereos when I used to
play with them in the 80s. I remember one of the causes being a non
insulated capacitor in the distributor ( points type). The other cause I
seem to remember is poor ground selection.
Sully
77 eleganza 2
Bellevue.
On Mon, Sep 4, 2017 at 2:23 PM Carl Stouffer wrote:
> kelvin wrote on Mon, 04 September 2017 14:07
>> Stereo issues. Or alternator.
>>
>> I have a "whine" thru my stereo speakers. Doesn't matter if I'm playing
>> a radio station or Bluetooth thru the phone. I'm going to guess a CD
>> will do it, too, but just realized I haven't tried that.
>>
>> My Stereo Guy suggested there was a problem with the stereo itself but I
>> just happen to have the same unit in my car so I swapped it. No problem
>> in my car but the same whine in the GMC. He gave me a "filter" to place
>> on the 12V wire but didn't seem to think that would do anything. He was
>> right.
>>
>> Sometimes louder than others and sometimes it even goes away. It does
>> seem to change with engine speed.
>>
>> Any ideas? I can install and wire sound systems but don't really
>> understand all the ins and outs.
>>
>> Thanks,
>> Kelvin
>> '73 23' in Eugene, OR
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> Is this something new?
>
> I noticed a whine coming from my stereo for a hundred miles or so just
> before my alternator conked out o9n the way to Moab a few years ago.
>
> --
> Carl Stouffer
> '75 ex Palm Beach
> Tucson, AZ.
> Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive,
> Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American
> Eagles,
> Solar battery charging. GMCSJ and GMCMI member
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] Whiny Stereo [message #323334 is a reply to message #323322] |
Mon, 04 September 2017 17:53 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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If you have a scope you can look at the alternator and be sure you have 3 "humps" per rotation. If not it won't have full output and be very noisy. When I replace the older 4D house battery my alternator got quiter. I think the impedance of the old battery was loading it down.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Whiny Stereo [message #323399 is a reply to message #323322] |
Tue, 05 September 2017 13:19 |
GatsbysCruise
Messages: 261
Registered: January 2017
Location: Waukegan, Illinois
Karma: 3
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I had a bad whine sound come through my boat radios. As I recall, the fix was a choke installed on the alternators output.
If I remember right, the choke was basically a #10 wire wrapped 10 times, connected inline of the alternator output.
A second wire, doesn't have to be #10, smaller is ok, wrapped around that coil, can't recall how many times, 10 or 20 times then both ends connected to ground. This cleared the whine from the alternator completely. I don't believe there were any caps used.
This is one of the most difficult interferrence sounds to remove. Even the boat dealers had no clue how to neutralize that whine. I searched the internet and found different so called fixes, and the choke was the fix. Best part, you can make your own. The coil is only about 1 to 1.5 inches diameter, very small and if it kills the noise, thats a great help.
EDIT: I thought I might mention that one of the fixes I was told to do was to have the alternator checked. I sent it to a shop and they said nothing was wrong. that cleared the regulator and diodes. The whine I had varied with RPM and was the Alternator. The choke worked for me.
Good luck.
slc
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center
[Updated on: Wed, 06 September 2017 11:38] Report message to a moderator |
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| Re: [GMCnet] Whiny Stereo [message #323421 is a reply to message #323322] |
Tue, 05 September 2017 20:49 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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Run a ground wire directly to the battery from the radio to test the ground. Make sure the antenna ground is not providing the ground for the radio. Check the voltage and load capability of the battery, and vary a load on the charging system while you listen to the radio to see if the noise is louder with more load. A simple tester (actually a toaster) is available at Harbor Freight for $20 that will help. Many times a battery going south will load the charging system to the point of noise, like John"s experience, especially when other loads come on line.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
[Updated on: Wed, 06 September 2017 01:10] Report message to a moderator |
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| Re: [GMCnet] Whiny Stereo [message #323443 is a reply to message #323395] |
Wed, 06 September 2017 12:53 |
kelvin
Messages: 608
Registered: February 2004
Location: Eugene, OR
Karma: 0
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Drove the coach to a local shop and had the alternator tested. There
were phase issues.
I found the receipt from 2003 and it's a Duralast, which has a lifetime
warranty. I'll be replacing it tonight and I'll let you now if it was
the fix.
If not, well, I have a new alternator and can look further. All the
grounding and 12V power issues might be applicable if the whine was
there 2 years ago when I installed this stereo. I have to admit I
thought alternator all along but it kept charging, so how could it be bad?
Shows how much I know about alternators...
Kelvin
'73 2' in Eugene, OR.
On 9/5/2017 9:34 AM, Kelvin Dietz wrote:
> I've gotten this answer from others, Bruce. I'm kind of leaning to
> this being the problem.
> The stereo was in there for a couple years with no problem and the
> whine started instantly during a trip last year.
>
> The alternator has been in there since 2003. Only about 30,000 miles
> but we know they work harder than your average car alternator.
>
> Time to take that sucker out and deliver to my local Auto Electric
> guy. At least we'll know THAT isn't the problem.
>
> Kelvin
>
>
> On 9/4/2017 4:43 PM, Bruce Hislop wrote:
>> That's called "Alternator Whine". The alternator is actually a
>> 3-phase AC generator. The AC is rectified to DC by 6 diodes inside
>> the alternator, but
>> the output is pulsing DC. The battery then acts as a big filter
>> capacitor to smooth the rectified AC into pure DC.
>>
>> Usually when we see alternator whine, it is a precursor to to an
>> alternator failure. Generally one of the 6 rectifier diodes has
>> shorted and is now
>> allowing a pulse of AC through. Fairly soon thereafter more diodes
>> fail and the alternator will not charge. The whine changes pitch
>> with the RPM of
>> then engine.
>>
>
>
> _______________________________________________
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> Unsubscribe or Change List Options:
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| Re: [GMCnet] Whiny Stereo [message #323445 is a reply to message #323443] |
Wed, 06 September 2017 13:20 |
GMC.LES
Messages: 505
Registered: April 2014
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Would this still be the case with radio whine on AM only when in a tunnel where the radio signal is lost? I have a VW that has been doing this for 7-8 years.
Les Burt
Montreal
'75 Eleganza 26'
> On Sep 6, 2017, at 1:53 PM, Kelvin Dietz wrote:
>
> Drove the coach to a local shop and had the alternator tested. There were phase issues.
> I found the receipt from 2003 and it's a Duralast, which has a lifetime warranty. I'll be replacing it tonight and I'll let you now if it was the fix.
>
> If not, well, I have a new alternator and can look further. All the grounding and 12V power issues might be applicable if the whine was there 2 years ago when I installed this stereo. I have to admit I thought alternator all along but it kept charging, so how could it be bad?
>
> Shows how much I know about alternators...
>
> Kelvin
> '73 2' in Eugene, OR.
>
>
>> On 9/5/2017 9:34 AM, Kelvin Dietz wrote:
>> I've gotten this answer from others, Bruce. I'm kind of leaning to this being the problem.
>> The stereo was in there for a couple years with no problem and the whine started instantly during a trip last year.
>>
>> The alternator has been in there since 2003. Only about 30,000 miles but we know they work harder than your average car alternator.
>>
>> Time to take that sucker out and deliver to my local Auto Electric guy. At least we'll know THAT isn't the problem.
>>
>> Kelvin
>>
>>
>>> On 9/4/2017 4:43 PM, Bruce Hislop wrote:
>>> That's called "Alternator Whine". The alternator is actually a 3-phase AC generator. The AC is rectified to DC by 6 diodes inside the alternator, but
>>> the output is pulsing DC. The battery then acts as a big filter capacitor to smooth the rectified AC into pure DC.
>>>
>>> Usually when we see alternator whine, it is a precursor to to an alternator failure. Generally one of the 6 rectifier diodes has shorted and is now
>>> allowing a pulse of AC through. Fairly soon thereafter more diodes fail and the alternator will not charge. The whine changes pitch with the RPM of
>>> then engine.
>>>
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
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| Re: [GMCnet] Whiny Stereo [message #323457 is a reply to message #323445] |
Wed, 06 September 2017 19:05 |
Bullitthead
Messages: 1411
Registered: November 2013
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When the signal drops in amplitude, automatic gain control (AGC) in the radio's tuner amp will increase the gain to keep the signal level steady for the preamp. That will also amplify the noise that was at a lower amplitude than the signal before entering the signal-loss zone (the tunnel or bridge overhead).
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] Whiny Stereo [message #323463 is a reply to message #323457] |
Wed, 06 September 2017 20:23 |
GMC.LES
Messages: 505
Registered: April 2014
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The whine changes with engine RPM, so I know it is alternator related. The car is a TDI, so no ignition system.
Several years ago when i tried resolving the issue, I figured it was something to do with the radio AGC circuit and suspected a faulty antenna as part of the problem. These antennas are amplified, so I put in a new one, but it didn't help. I also swapped the alternator with a used spare. Got the same results, so I gave up. I'm now wondering if I have two bad alternators. They both maintain good voltage and output under varying loads, and haven't gotten worse over several years of daily use.
Les Burt
Montreal
'75 Eleganza 26'
> On Sep 6, 2017, at 8:05 PM, Terry wrote:
>
> When the signal drops in amplitude, automatic gain control (AGC) in the radio's tuner amp will increase the gain to keep the signal level steady for
> the preamp. That will also amplify the noise that was at a lower amplitude than the signal before entering the signal-loss zone (the tunnel or bridge
> overhead).
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
>
>
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| Re: [GMCnet] Whiny Stereo [message #323469 is a reply to message #323443] |
Wed, 06 September 2017 21:11 |
kelvin
Messages: 608
Registered: February 2004
Location: Eugene, OR
Karma: 0
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Alternator installed and I don't have any whine at idle or when revving
it. The problem is that's not unusual. Mostly have to drive it a
little before the whine starts. No time for that tonight. Loading for
a trip. I'll know tommorrow morning when we hit the road to Port
Townsend, WA.
Kelvin
On 9/6/2017 10:53 AM, Kelvin Dietz wrote:
> Drove the coach to a local shop and had the alternator tested. There
> were phase issues.
> I found the receipt from 2003 and it's a Duralast, which has a
> lifetime warranty. I'll be replacing it tonight and I'll let you now
> if it was the fix.
>
> If not, well, I have a new alternator and can look further. All the
> grounding and 12V power issues might be applicable if the whine was
> there 2 years ago when I installed this stereo. I have to admit I
> thought alternator all along but it kept charging, so how could it be
> bad?
>
> Shows how much I know about alternators...
>
> Kelvin
> '73 2' in Eugene, OR.
>
>
> On 9/5/2017 9:34 AM, Kelvin Dietz wrote:
>> I've gotten this answer from others, Bruce. I'm kind of leaning to
>> this being the problem.
>> The stereo was in there for a couple years with no problem and the
>> whine started instantly during a trip last year.
>>
>> The alternator has been in there since 2003. Only about 30,000 miles
>> but we know they work harder than your average car alternator.
>>
>> Time to take that sucker out and deliver to my local Auto Electric
>> guy. At least we'll know THAT isn't the problem.
>>
>> Kelvin
>>
>>
>> On 9/4/2017 4:43 PM, Bruce Hislop wrote:
>>> That's called "Alternator Whine". The alternator is actually a
>>> 3-phase AC generator. The AC is rectified to DC by 6 diodes inside
>>> the alternator, but
>>> the output is pulsing DC. The battery then acts as a big filter
>>> capacitor to smooth the rectified AC into pure DC.
>>>
>>> Usually when we see alternator whine, it is a precursor to to an
>>> alternator failure. Generally one of the 6 rectifier diodes has
>>> shorted and is now
>>> allowing a pulse of AC through. Fairly soon thereafter more diodes
>>> fail and the alternator will not charge. The whine changes pitch
>>> with the RPM of
>>> then engine.
>>>
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
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> Unsubscribe or Change List Options:
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| Re: [GMCnet] Whiny Stereo [message #323481 is a reply to message #323463] |
Wed, 06 September 2017 23:23 |
Bullitthead
Messages: 1411
Registered: November 2013
Karma: 5
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I had a Hyundai a few years ago that I fixed the radio noise with a ground wire from the alternator bracket to the shock tower, which had a factory ground right to the battery. Even though checking with a voltmeter and a test light showed bracket was grounded, connecting the test light changed the noise, and directly grounding with a jumper wire silenced it. That had to be just luck finding that as I was just testing the test light! I don't remember whether any dissimilar metals were in the setup; except for the bolts, it may have been all aluminum.
Terry Kelpien
ASE Master Technician
73 Glacier 260
Smithfield, Va.
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| Re: [GMCnet] Whiny Stereo [message #323488 is a reply to message #323481] |
Thu, 07 September 2017 02:07 |
JohnS
Messages: 126
Registered: December 2014
Location: Vacaville, CA
Karma: -2
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Bruce mentioned that a bad diode in the alternator can be a source of that noise. That has been my experience with Delcotron alternators and alternators in light aircraft over the years. One diode can be bad and the unit will put out close to it's rated output, (so we may not notice the problem) but it will introduce a lot of noise. Filters seldom help except for improving the cash flow of those who sell them.
John
John Shutzbaugh, Vacaville, CA, ncserv@aol.com;
78 Buskirk stretch, "What were we thinking?"
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