Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Loud POP
Loud POP
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th May 2014, 10:44 PM   #1
BoTcH2001 is offline BoTcH2001
diyAudio Member
 
Join Date: May 2014
Default Loud POP

Hello All,

My system is making a LOUD pop sound when changing sources, turning on/off, turning vol up from zero.
I'll explain below the setup, history and my trouble shooting

I have a Pioneer P6900UB headunit, connected to 2 sony xplod XM475.
1 amp powers up the 4 door speakers, and the other powers up 2 rear 6x9s and my rockford punch.

when I first put in the system, It was all RCA wired, and worked perfectly, except only my front left channel (2 left doors) had a little pop sound when changing sources, turning unit on/off, turning volume up from 0.
I thought I could live with that, especially that all the system was bought second hand from various seller...I had no doubt that it was the HU, especially that it does the same when using the other amp.

Then all of a sudden the pop was too loud to stand, knowing that the front RCA out from the HU is faulty, I moved the front channels to High level inputs, and the pop was still there, only as low as it was previously, and that I could live with....again believing that its a faulty headunit.

all that was a year ago,
Yesterday, a LOUD pop came from my rear left speaker, I checked wiring and found that the wire out of the amp was loose, so I tighten, sound was gone.
Trip back home, functioning normally.

Then again today, the pop reappeared, as loud as before, from both speakers and the sub :S
checked wiring, all perfect, checked ground, everything...so I thought I'd leave it alone till I get back home, as I drove sound was gone...then I hit a street bump...Sound reappears....I suspected loose wiring.

Now I'm back home, with 3 hours of taking the whole system apart, and putting it back together, still sounds the same.
I'm still thinking it's the headunit...so trying to isolate the cause, and find a work around, I removed the remote power on going into the amp.
and with the headunit turned on, I connect the remote into the amp, and it works flawlessly.

I'm thinking this has to do with the remote on/mute signal from the head unit to the amp, weird enough it happens in one amp only.

I connected the remote wire to a relay inline with the amp, hoping that this will cause a delay in the power on signal, making the pop fade...but still no joy.

what are your thoughts on this?
  Reply With Quote
Old 24th May 2014, 11:06 PM   #2
BoTcH2001 is offline BoTcH2001
diyAudio Member
 
Join Date: May 2014
Further to the above,
Since I already have high level inputs in the trunk, I tried connecting the remote from that, and still the pop exits with changing source, powering on/off
Does anyone know some sort of device that would delay the power on signal from the remote....I think that might be a good work around
Even though I'd like to know if it's really the Head unit or the amps that iscausing these pops
  Reply With Quote
Old 24th May 2014, 11:09 PM   #3
Perry Babin is offline Perry Babin  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Check the RCA output shield ground on the head unit.
__________________
Anyone who purchased the repair tutorial, email me (babin_perry@yahoo.com) if you want to download the latest version.
  Reply With Quote
Old 24th May 2014, 11:11 PM   #4
BoTcH2001 is offline BoTcH2001
diyAudio Member
 
Join Date: May 2014
Quote:
Originally Posted by Perry Babin View Post
Check the RCA output shield ground on the head unit.
RCA has been checked, I already had it grounded to the head unit as it was making a whining sound with the engine revs
  Reply With Quote
Old 24th May 2014, 11:22 PM   #5
Perry Babin is offline Perry Babin  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
If the shield ground was open, the RCA shields likely contacted a 12v wire. When that happened, the center conductor may have also made contact with the 12v source and damaged the muting transistors.

A remote delay won't fix the pop when you change sources.
__________________
Anyone who purchased the repair tutorial, email me (babin_perry@yahoo.com) if you want to download the latest version.
  Reply With Quote
Old 24th May 2014, 11:30 PM   #6
BoTcH2001 is offline BoTcH2001
diyAudio Member
 
Join Date: May 2014
Quote:
Originally Posted by Perry Babin View Post
If the shield ground was open, the RCA shields likely contacted a 12v wire. When that happened, the center conductor may have also made contact with the 12v source and damaged the muting transistors.

A remote delay won't fix the pop when you change sources.
You are making perfect sense
But I doubt that they had been in contact with a 12v wire...All my +ve wires are well isolated.

Or maybe the transistors were burnt on their own, all this setup is pretty old now
  Reply With Quote
Old 24th May 2014, 11:32 PM   #7
BoTcH2001 is offline BoTcH2001
diyAudio Member
 
Join Date: May 2014
What doesn't make sense though, how could both transistors fail at the same time.
I suppose it's a transistor per RCA pair
  Reply With Quote
Old 24th May 2014, 11:38 PM   #8
Perry Babin is offline Perry Babin  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
The muting transistors aren't likely to fail on their own.

If the shield ground was open, the shields contacted a 12v source.

Maybe the damage wasn't done all at once.

Yes. One transistor pair per pair of RCAs.

It's also possible that there is a problem with one of the amps.

If you measure the DC voltage on the input RCA shields of both amplifiers, do you rean anything more than a fraction of a volt?
__________________
Anyone who purchased the repair tutorial, email me (babin_perry@yahoo.com) if you want to download the latest version.
  Reply With Quote
Old 26th May 2014, 11:31 AM   #9
BoTcH2001 is offline BoTcH2001
diyAudio Member
 
Join Date: May 2014
Quote:
Originally Posted by Perry Babin View Post
The muting transistors aren't likely to fail on their own.

If the shield ground was open, the shields contacted a 12v source.

Maybe the damage wasn't done all at once.

Yes. One transistor pair per pair of RCAs.

It's also possible that there is a problem with one of the amps.

If you measure the DC voltage on the input RCA shields of both amplifiers, do you rean anything more than a fraction of a volt?
I was able to identify the faulty equipment while testing the RCA shields voltage (didn't exceed 0.2V)
I noticed that the sub was moving in and out ( even though the headunit was on AUX source with no input).
I took out the sub's RCA, and still the sub was moving!!!!
I took out the rear speakers' RCA, then the sub stopped moving.
Putting in the sub's RCA, sub moves.
there is a voltage fluctuation on the sub output, and the rear speakers output from the amp.

that last i did, was try the RCAs in the amp i use for my front speakers, no POPs at all, i tried both rear and sub RCAs in my front amp, and they work flawlessly.

so it's definitely the amp, but do you think it's something that is fixable, or i will have to replace it? :S
I'm afraid that it was the headunit that caused it to blow....even though i doubt it, but you never know.
  Reply With Quote
Old 26th May 2014, 06:54 PM   #10
Perry Babin is offline Perry Babin  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
To clarify, only one amplifier has problems with the audio popping (and/or other problems) when ANY of the RCAs of the head unit are plugged into the rear input on that amp. ALL of the head unit outputs work perfectly when plugged into ANY of the inputs except for the rear input on one amplifier. Is that correct?

Push on the RCAs while looking at the connections on the bottom of the board. Do you see any connections broken like the one in the attached image?

The damage may not be as severe and may take a lighted magnifying glass to see the break due to all of the silkscreen in that area.
Attached Images
File Type: jpg IMG_0180x.jpg (172.0 KB, 42 views)
__________________
Anyone who purchased the repair tutorial, email me (babin_perry@yahoo.com) if you want to download the latest version.
  Reply With Quote

Reply


Loud POPHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
LM3886 loud pop when turned off nige838 Chip Amps 36 8th October 2011 12:44 AM
Loud pop every few seconds? toufu Analogue Source 1 27th April 2010 09:09 PM
Loud pop on Squelch FoKale Solid State 0 9th May 2009 10:32 PM
206ES-R loud pop on startup tubesdude Multi-Way 1 13th August 2007 06:44 AM
Loud POP 555mkII moderate volume. digital desire Solid State 2 28th February 2007 01:02 AM


New To Site? Need Help?

All times are GMT. The time now is 09:22 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki