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

ADS PQ20 amp- anyone worked on?
ADS PQ20 amp- anyone worked on?
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
Thread Tools Search this Thread
Old 24th March 2007, 01:48 PM   #1
GordonW is offline GordonW  United States
diyAudio Member
GordonW's Avatar
Join Date: Mar 2005
Location: Marietta/Moultrie GA
Default ADS PQ20 amp- anyone worked on?

Got a working ADS PQ20 amp... it's fine, except it creates ground loop noise (alternator whine) with EVERY component combination its been connected to.

I have a FAINT memory, of someone once telling me that there was an isolation diode (or cap, or whanot), between chassis ground and signal ground... and that the diode/cap/whatever could be blown, by operating the amp with a bad main ground... at which point, the chassis ground would short to signal ground... voila, ground loop...

Can anyone either verify or debunk my recollection? And if it's true, any clues on WHERE the little bugger is in the amp?


Speaker Design, Restoration and Repair- since 1985.
  Reply With Quote
Old 24th March 2007, 08:14 PM   #2
Perry Babin is offline Perry Babin  United States
diyAudio Member
Join Date: Nov 2003
Location: Louisiana
I'm not sure about the ADS but some amps have a diode between the chassis ground and the audio (RCA shield) ground. When the diode shorts, it will cause ground loop noise. If the amp had a direct short between the RCA shields and the chassis ground, it's likely a shorted diode. If the resistance between the two grounds is relativly high, the problem is likely something else.

Does it play without noise on the bench?
  Reply With Quote


ADS PQ20 amp- anyone worked on?Hide 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
a/d/s pq20 for sale?? mike49504 Car Audio 15 27th March 2012 09:38 PM
Wanted: A/d/s/ Pq20 Jonny Hotnuts Swap Meet 2 4th January 2008 07:58 AM
a/d/s pq20 question mike49504 Car Audio 4 20th December 2007 04:52 AM
ads pq20 mike49504 Car Audio 3 8th August 2007 01:11 AM

New To Site? Need Help?

All times are GMT. The time now is 05:21 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio