Radio buzz only with 4 RCA's
Thread Starter
Instructor
Joined: Jun 2008
Posts: 233
Likes: 9
From: Marietta Ga
Radio buzz only with 4 RCA's
I am in the process of troubleshooting radio engine noise in a new install in my '73 and found that when front or rear RCA's are pulled at the amp the noise stops. Why would that be?
I'm hoping this leads me to something I can fix.
Amp ground, amp positive and head unit B+ are connected directly at the battery.
This is a retro sound head unit with 4 channel Sound Ordnance amp and Rockford Fosgate 6X9's
Noise is constant for Aux input or tuner...no different.
I'm hoping this leads me to something I can fix.
Amp ground, amp positive and head unit B+ are connected directly at the battery.
This is a retro sound head unit with 4 channel Sound Ordnance amp and Rockford Fosgate 6X9's
Noise is constant for Aux input or tuner...no different.
Tech Contributor
Joined: May 2003
Posts: 7,035
Likes: 134
From: North Augusta, SC
Does the noise change pitch/frequency with engine RPM?
If yes to above, a pair of GLI's between HU and amp should eliminate it.
It may be fixable with a different ground location. Try connecting amp ground to closest metal ground point available (you can leave current ground wire there for the test, but disconnect it at one end).
If yes to above, a pair of GLI's between HU and amp should eliminate it.
It may be fixable with a different ground location. Try connecting amp ground to closest metal ground point available (you can leave current ground wire there for the test, but disconnect it at one end).
Thread Starter
Instructor
Joined: Jun 2008
Posts: 233
Likes: 9
From: Marietta Ga
Yes, it does change with engine RPM. I'll try the ground change first then go after the GLI's.
Will probably ground to a seat bolt and see how that goes.
I just don't understand why it goes away with front or rear RCA's disconnected.
Will probably ground to a seat bolt and see how that goes.
I just don't understand why it goes away with front or rear RCA's disconnected.
Tech Contributor
Joined: May 2003
Posts: 7,035
Likes: 134
From: North Augusta, SC
Moving the amp ground may help, but probably not. If/when you get the GLI's try using one on just the rears first, that would leave your front signal pure at the amp (IMO GLI's don't have any effect on sound quality, but some would disagree).
