Dual secondaries with one bridge - Page 5 - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 18th October 2011, 02:14 PM   #41
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
you must add in the trace/wire routes at the PCB to complete each circuit.

Take just the Power Amp.
Look at the source @ P9 & P10.
That must be a circuit.

Remember, circuit is effectively shorthand for circular route. Electricity must flow around that route (from beginning right back to end) if it is to flow at all.
__________________
regards Andrew T.
  Reply With Quote
Old 18th October 2011, 02:51 PM   #42
diyAudio Member
 
Join Date: Apr 2007
I have all the ground conections indicated. All the tracea are there. Each blocck is a PCB p9 p10 are entry pins for power amp pcb.
  Reply With Quote
Old 18th October 2011, 02:53 PM   #43
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Including the PSU as batteries in that diagram hides the very thing we want to see! Is the preamp PSU grounded via the preamp PCB or via the PSU PCB to the star (or both?).

You have two grounds coming off the star: chassis via 10 ohms and the 'ground' symbol. If the 'ground' symbol is meant to be external ground (e.g. via third pin of supply) then this should go to the chassis, not the star.

Is there a ground connection at the signal input socket? You haven't marked one, and there should not be one, but people sometimes forget and use non-insulated sockets so creating a hum loop.
  Reply With Quote
Old 18th October 2011, 04:18 PM   #44
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
The signal comes in Hot) at P10. The signal goes out Cold) at P9. Where is the circuit for the signal current to flow around?
Without a complete circuit the signal current cannot flow !!!!!
__________________
regards Andrew T.
  Reply With Quote
Old 18th October 2011, 04:43 PM   #45
diyAudio Member
 
Join Date: Apr 2007
DF96 the preamp PSU is grounded in the preamp PCB not in star of power amp. The 'ground' symbol is threre to indicate the star nothing else.
Andrew, The complete circuit is exactly the jlh 2005 update circuit class a.
  Reply With Quote
Old 18th October 2011, 05:03 PM   #46
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Kz,
your job, if you want to get to the bottom of your hum enquiry, is to trace out the three circuits as I described and from there identify which if any of the routes share a trace or wire between two or more of those circuits.

I cannot and will not do that for you.
I cannot because I do not have the PCB in front of me, nor do I have the Power Amplifier with all it's cable routes open in front of me.
__________________
regards Andrew T.
  Reply With Quote
Old 18th October 2011, 06:03 PM   #47
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
OK. The ground symbol is usually used to indicate an actual connection, typically to chassis.

Your diagram show one channel. How are the two channels wired? There should be one and only one ground connection between them. Possibly not even that, if the source joins the two channels together.
  Reply With Quote
Old 18th October 2011, 07:40 PM   #48
diyAudio Member
 
Join Date: Apr 2007
Andrew df96 thanks for the responces so far. By all means I do not anyone to do anything for me. I done that Andrew pointed out I found two areas where the signal ground is shared by other parts of the circuit. One in the preamp and one and one in power amp. I quicly seperated them temporarely and it is true that the noise reduced a bit. This means that this is the problem and I will try to fix the other also. I will report as soon as I will do it. Thanks a lot Andrew for your help.
  Reply With Quote
Old 19th October 2011, 05:55 AM   #49
diyAudio Member
 
Join Date: Apr 2007
I stayed late yesterday and I made the changes I mention in my previous post. I tested the noise with with scope and some small earphones and is really less. Andrew you made a point. The area that was shared was about 3 and half centimeters, so I bypassed this one and it is better. Late in the afternoon, I will test it also in my very sensitive (103 db) speakers and I will also report. But so far it seems solved. Thanks
  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
One transformer with 4 secondaries or two transformers with dual secondaries Baka Chip Amps 5 28th November 2008 06:39 AM
Reopening an unfinished debate: Dual bridge vs. Single Bridge xiphmont Chip Amps 15 26th February 2008 07:22 PM
Need help with dual secondaries in series glt Chip Amps 5 12th November 2007 06:41 AM
Center Tap vs Dual Secondaries StalfoS Chip Amps 6 18th March 2005 10:10 PM


New To Site? Need Help?

All times are GMT. The time now is 05:25 AM.


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