Dual Mono PSU with shared earth.. - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 25th April 2005, 08:43 PM   #1
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Default Dual Mono PSU with shared earth..

how to implement? I've been building an amp for a friend of mine. The Cleo V by triode Dick. It uses a dual mono PSU but i've used a common earth. (I'm having major HUMM problems)

When discussing that with another friend and forum member Mark25, he suggested that I change the phase on one channel because your transformers should have the same phase when you have a common earth. I guess he was right because the amp is a lot quiter...but now I'm curious...:
How do you guys implement such a scheme? 2 seperate earths or a common one...and if one earth...then should they be in or out of phase?

Regards,
Bas
  Reply With Quote
Old 26th April 2005, 09:37 AM   #2
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Default How many lumps Sir? 1, 2 or 3

Bas,

If the dual power suplies and amps are on the same chassis, then follow the same rules as normal for a single PSU.
Determine the main frequency of the hum - 50Hz or 100Hz or sometimes a sharp buzz containing lots of harmonics, and report back

If the PS is remote, then the problem may be more complex.
  Reply With Quote
Old 26th April 2005, 09:41 AM   #3
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Hallo John,

It's all on the same chassis. What are the normal rules?
My rules are simple :
If I build an amp simple there is one start earthing point all roads lead to it.

I did the same with this amp..but apparently different rules apply? Or at least there are some extra considerations.. The plot thickens because there is a phono amp with seperate supply in there also. I have made a seperate star earth for that and one wire from that star earth to the main one.

Regards,
Bas

Click the image to open in full size.
  Reply With Quote
Old 26th April 2005, 09:53 AM   #4
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Default Baz' rulz

Bas,

What is the hum frequency? Or describe how it sounds...

What is the orientation of the transformers'?
  Reply With Quote
Old 26th April 2005, 09:55 AM   #5
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Click the image to open in full size.

100Hz with lotsa other noise...hash
  Reply With Quote
Old 26th April 2005, 10:05 AM   #6
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Bas,

Firstly you need to turn your output transformrts 90 deg.

Gotta go to work. I'll try to pick this up there....
  Reply With Quote
Old 26th April 2005, 10:13 AM   #7
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Quote:
Firstly you need to turn your output transformrts 90 deg.
You mean rebuild the amp?
  Reply With Quote
Old 26th April 2005, 11:11 AM   #8
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Quote:
Originally posted by Bas Horneman
You mean rebuild the amp?
'Fraid so. You have coupled your mains transformers straight into your output transformers. You could turn either the output transformers or the mains transformers. Turning the mains transformers would be better because you have pointed their hum at your delicate audio circuitry.

You also appear to have AC wiring running down the left hand side that then feeds a rectifier and capacitor, but passes near to the inputs. Very bad. Move that rectifier/capacitor and regulator up to the noisy end of the chassis and feed clean DC past the inputs.
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 26th April 2005, 11:35 AM   #9
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Hi EC8010,

Those small transformers are chokes.

Cheers,
Bas
  Reply With Quote
Old 26th April 2005, 11:42 AM   #10
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
So are the big ones the output transformers, and the little one at the end the mains transformer?
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  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
s/500 dual to mono joegio Pass Labs 3 27th April 2009 12:12 AM
making dual mono jack from single mono jack dubmunkey Analog Line Level 2 12th October 2006 02:16 PM
Why dual mono? preiter Chip Amps 11 21st September 2006 09:37 PM
Single Mono's or Dual Mono? Tazzy Pass Labs 8 3rd October 2002 02:03 PM
Dual Mono - Anti Mono Power Supplies pmkap Everything Else 3 16th February 2002 05:10 AM


New To Site? Need Help?

All times are GMT. The time now is 04:51 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