How on earth...? - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 6th April 2004, 12:29 PM   #1
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
Default How on earth...?

I have had a few problems with my hi-fi system lately after (but not all resulting from) the addition of a sub woofer.

I had located and remedied a problem in the sub woofer controller circuit and another in my CD player but somehow, things just didn't sound right.

The music played, imaging was OK, but the timing was out, clarity a little impaired and it just didn't sound right.

Today I tracked down the problem. I have a separate PSU for each channel of my Gainclone amp and on one supply, the neutral mains connection had become disconnected.

BUT the PSU still measured +/- 26 VDC on its output and I can't understand how this could be.

At first, I thought that perhaps the circuit was being made through the zero volt wires in the amp circuit but the PSU still measured correctly even without the amp being connected.

Can anybody explain this one?
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 6th April 2004, 12:42 PM   #2
diyAudio Member
 
Join Date: May 2002
Location: Switzerland
Quote:
I have a separate PSU for each channel of my Gainclone amp and on one supply, the neutral mains connection had become disconnected.
It depends on what you actually mean by "neutral mains connection".

If it is the conection between the tranformer center-tap and ground then the voltage might very well look symmetric (to some degree at last) if measured without load.

The best thing to understand what was going on would be to draw a small diagram showing where exactly the connection was missing.

Regards

Charles
  Reply With Quote
Old 6th April 2004, 12:51 PM   #3
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
The connection that was 'broken was from the mains supply to the input (fuse) of the PSU.

Click the image to open in full size.

(Hope thiswill do, I have to go out now)
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote
Old 6th April 2004, 01:15 PM   #4
owen is offline owen  United Kingdom
diyAudio Member
 
Join Date: Mar 2004
Location: Shilton
Default Easy....

The break works like a capacitor.... AC voltage would then fluctuate as normal (50 Hz cycles), but would be massively current limited. Your break may well have had a small touch contact patch as well, that would bring the current availibility up to a more usable level, but transients would have been delivered from the meagre charge in the caps.. no small wonder the sound was 'off'....

Breaks in the flex really does it for DC....

Owen
  Reply With Quote
Old 6th April 2004, 01:55 PM   #5
Nuuk is offline Nuuk  United Kingdom
diyAudio Member
 
Nuuk's Avatar
 
Join Date: Feb 2003
Location: Somerset, SW England
Thanks for the reply Owen. The break was 'complete' ie the wire had come out of the terminal block altogether.

As you say, 'no wonder the sound was off'
__________________
The truth need not be veiled, for it veils itself from the eyes of the ignorant.
  Reply With Quote

Reply


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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hi All in the EARTH zeonrider Car Audio 0 30th December 2006 05:29 PM
Earth again Pbassred Solid State 20 10th July 2005 07:44 AM
Car amp earth sidewz Car Audio 0 20th April 2004 10:47 PM
Earth Connection Sherman Chip Amps 16 16th April 2004 12:59 PM
Should I come down to Earth ? Prof Chip Amps 19 12th June 2003 02:05 PM


New To Site? Need Help?

All times are GMT. The time now is 05:48 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2