Humming Noise from Kenwood X994/8016BT

Trust_In_Thrust · 9th October 2010, 19:02

I recently added a second Amp JBL 3501 to my setup and i am getting a humming noise which is constant ,low frequency hum from speakers (attached to JBL 1004 ) .I checked complete wiring , amp , etc .Finally when i use a different head unit it all goes away.The noise is even present when i do not start the car .The noise blockers (Isolation Amplifiers ) have not been of any help.The amplitude of hum is not affected by doing anything.

I finally ended up giving the head unit to Kenwood Service Station in Rajouri Garden today.They tried removing few components called teedeas in local language but the humming persisted .So they will be sending the head unit to Kenwood office in Noida .He has said you will get the unit in 7 days .

Anyone know what could have been the issue .

thelord · 9th October 2010, 21:39

If the humming goes away with a different unit, then it's clearly the case of a faulty HU. Get it replaced/repaired if it's under warranty. Most common reasons of HU's going kaput are installers hot-swapping RCAs or not disconnecting the battery terminal before starting the install. I know of many Pioneer HU sets that started giving a strange whine when installers swapped RCAs when the units were running. The solution could be as simple as replacing a few capacitors or resistors (gurus know better). Or there is a famous Pioneer ground loop fix (search the forums). Good for you that you figured out the culprit straight away, otherwise finding out the source of noise/whine can be a very challenging and frustrating task.

DrBoom · 11th October 2010, 11:22

Any sort of intermittent noise that is gained through the cars audio systems identifies a ground loop, but the interference could be caused by the cars computer. This is one of the issues so most reputable car audio installers will do their upmost to run power and RCA wires as furthest possible so such noise will not be generated when the audio system is up and running. Secondly, if the head unit was an issue, I am assuming it is poor ground in the RCA output of the head unit itself.

Hopefully the issue will be rectified or you may get a replacement but before you take hold of it, ask the shop to "bench test" it to see that no noise is present but bear in mind the audio system will sound different in an "open" environment compared to a cars limited environment.

Good luck mate!

9th October 2010, 19:02	#1
Trust_In_Thrust BANNED Join Date: Nov 2008 Location: New Delhi Posts: 768 Thanked: 349 Times	Humming Noise from Kenwood X994/8016BT I recently added a second Amp JBL 3501 to my setup and i am getting a humming noise which is constant ,low frequency hum from speakers (attached to JBL 1004 ) .I checked complete wiring , amp , etc .Finally when i use a different head unit it all goes away.The noise is even present when i do not start the car .The noise blockers (Isolation Amplifiers ) have not been of any help.The amplitude of hum is not affected by doing anything. I finally ended up giving the head unit to Kenwood Service Station in Rajouri Garden today.They tried removing few components called teedeas in local language but the humming persisted .So they will be sending the head unit to Kenwood office in Noida .He has said you will get the unit in 7 days . Anyone know what could have been the issue . Last edited by Trust_In_Thrust : 9th October 2010 at 19:04.
	() Thanks

9th October 2010, 21:39	#2
thelord BHPian Join Date: May 2009 Location: Orange County, CA Posts: 278 Thanked: 5 Times	If the humming goes away with a different unit, then it's clearly the case of a faulty HU. Get it replaced/repaired if it's under warranty. Most common reasons of HU's going kaput are installers hot-swapping RCAs or not disconnecting the battery terminal before starting the install. I know of many Pioneer HU sets that started giving a strange whine when installers swapped RCAs when the units were running. The solution could be as simple as replacing a few capacitors or resistors (gurus know better). Or there is a famous Pioneer ground loop fix (search the forums). Good for you that you figured out the culprit straight away, otherwise finding out the source of noise/whine can be a very challenging and frustrating task.
	() Thanks

11th October 2010, 11:22	#3
DrBoom Newbie Join Date: Sep 2010 Location: Sydney Australia Posts: 24 Thanked: 28 Times	Any sort of intermittent noise that is gained through the cars audio systems identifies a ground loop, but the interference could be caused by the cars computer. This is one of the issues so most reputable car audio installers will do their upmost to run power and RCA wires as furthest possible so such noise will not be generated when the audio system is up and running. Secondly, if the head unit was an issue, I am assuming it is poor ground in the RCA output of the head unit itself. Hopefully the issue will be rectified or you may get a replacement but before you take hold of it, ask the shop to "bench test" it to see that no noise is present but bear in mind the audio system will sound different in an "open" environment compared to a cars limited environment. Good luck mate!
	() Thanks