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 28th March 2004, 12:31 PM   #1
diyAudio Member
 
Join Date: Dec 2003
Location: At 35,000 ft
Send a message via ICQ to blackreplica Send a message via AIM to blackreplica Send a message via MSN to blackreplica Send a message via Yahoo to blackreplica
Default GC Power Supply Trouble

Hi guys

Today I used the supplied diagram to wire the twin secondaries of my transformer. I measured the AC voltage on the secondaries and got a perfect 25-0-25.

That part's fine. But once I wired the secondaries to the rectifier and turned the power on, I got a terrible mechanical "rrrrrrr" sound and the transformer and rectifier started to get VERY hot in just a few seconds. I'm thinking something must have shorted so I quickly shut it off.

What in the world could I be doing wrong? I even have 2 rectifiers and tried it with both but as long as I connect the marked AC pin to ANY other pin on the rectifier, I get that horrible sound!

The problem is that on my rectifier, only one AC pin and one + pin is marked. The other 2 are not. I assume that the corresponding AC pin is diagonally across from the marked AC pin, and same for the + pin right? Even so, I did try wiring the AC pin to every other pin, but no matter what, that sound/heat persists. The transformer works fine when its not connected to the recitifer and I measure the voltages off the secondaries.

Since then, i managed to get the pin diagram for the recitifer just to make sure i got things right and i did. So i just cant understand whats happening

I dare not go any further until I am able to solve this problem and I hate to ask simple questions like this but i've looked pretty much everywhere and no one has mentioned a similar problem. I even scoured the whole decibel dungeon site and couldn’t find anything that could help my problem.

Hope to get some help, thanks so much

P.S the recitifier is a generic 100V 25A bridge from www.partsexpress.com
  Reply With Quote
Old 28th March 2004, 12:43 PM   #2
SvErD is offline SvErD  Norway
diyAudio Member
 
SvErD's Avatar
 
Join Date: Jan 2002
Location: Norway
Swap the leads of ONE of your secondaries and everything should be OK.
__________________
I don't suffer from insanity, I enjoy every minute of it!
  Reply With Quote
Old 28th March 2004, 12:56 PM   #3
diyAudio Member
 
Join Date: Dec 2003
Location: At 35,000 ft
Send a message via ICQ to blackreplica Send a message via AIM to blackreplica Send a message via MSN to blackreplica Send a message via Yahoo to blackreplica
Hi sverd,

are you referring to the AC leads? I think i tried that, but it didnt work either...unless you mean the 0V leads?(its a twin secondary)

Apologies for the confusion
  Reply With Quote
Old 28th March 2004, 01:18 PM   #4
SvErD is offline SvErD  Norway
diyAudio Member
 
SvErD's Avatar
 
Join Date: Jan 2002
Location: Norway
Yes I mean the AC leads of one of the secondaries. If you could make an accurate sketch of how you've connected everything it would be easier to explain.
__________________
I don't suffer from insanity, I enjoy every minute of it!
  Reply With Quote
Old 28th March 2004, 01:33 PM   #5
diyAudio Member
 
Join Date: Dec 2003
Location: At 35,000 ft
Send a message via ICQ to blackreplica Send a message via AIM to blackreplica Send a message via MSN to blackreplica Send a message via Yahoo to blackreplica
Ok i've drawn a rough sketch(attached)

originally, i connected black to yellow(0V) with red and orange going to the AC terminals of the recitifer. Done this way, i get 25V from either of the secondaries to the 0V secondary and 50V from one AC secondary to the other AC secondary. When i connect this to the rectifier, i get that terrible sound and heat

Then i followed your advice and tried to swap one of the secondaries. So now the red and black wire is switched, i.e. red and yellow are joined together(0V) and black and orange are the AC leads going to the rectifier. Done this way, i get 25V from either secondary to 0V but when i measure voltage across the AC terminals, i get a very mysterious 0V AC on my multimeter. When i hook up the rectifier everything seems ok, but i get no DC voltage off the rectifier DC output terminals.

Doesnt seem to be working at all. I'm very disheartened any idea what i'm doing wrong?

Kevin
Attached Images
File Type: jpg transformer.jpg (8.0 KB, 1452 views)
  Reply With Quote
Old 28th March 2004, 01:36 PM   #6
matjans is offline matjans  Netherlands
diyAudio Member
 
matjans's Avatar
 
Join Date: Aug 2003
Location: Utrecht, NL
Send a message via MSN to matjans
ok then, to avoid confusion and to prevent anybody from getting killed, the rectifier bridges should be hooked up like this:
Click the image to open in full size.

I've used the standard (EU?) toroid color coding scheme. If you're not sure, just check the resistance. red-yellow should have some resistance, the other pair too. infinite resistance means you've got the wrong wire (not the same secondary winding)

this should do it...

/matti
__________________
Si fractum non sit, noli id reficere!
  Reply With Quote
Old 28th March 2004, 01:42 PM   #7
diyAudio Member
 
Join Date: Dec 2003
Location: At 35,000 ft
Send a message via ICQ to blackreplica Send a message via AIM to blackreplica Send a message via MSN to blackreplica Send a message via Yahoo to blackreplica
Oh dear,

You mean i need to use both my rectifiers(i originally bought the second as a spare). The colour coding is a little different to the one on my transformer though, how do i interpret it? Is there a way for me to just use one? My transformer has twin 25V secondaries. I'm aiming to get 25V AC to 36V ac for the rails of the amp(my gc will be the LM3875 version)

BTW i hope my nick doesnt offend. I got an email once from a guy who asked me to change it but i think people misunderstand, its actually a tongue-in-cheek kinda name, not meant to offend or anything. Maybe thats why hardly anyone helped me in my earlier threads

Just to update:

I have tested the leads as mentioned in the above post for resistance. I have found the matching secondaries and tried wiring them to the rectifier AC terminals again as explained in the diagram above. It made that sound/heat again!!! What in the world...??
  Reply With Quote
Old 28th March 2004, 02:07 PM   #8
matjans is offline matjans  Netherlands
diyAudio Member
 
matjans's Avatar
 
Join Date: Aug 2003
Location: Utrecht, NL
Send a message via MSN to matjans
don't forget to use a fuse in front of the toroid, that might make it a little safer...

i can't reccomment using only one bridge, i've tested it and somehow it degrades the sound. makes it sound very dull.

what are the rectifier's specs? are you shure you haven't blown them up in previous attempts to get a working bridge ?

25v secondaries will, after rectification provide you with ~35V DC.

(ans yes, i think your nick might be the reason for not getting too much help on these fora)
__________________
Si fractum non sit, noli id reficere!
  Reply With Quote
Old 28th March 2004, 08:56 PM   #9
diyAudio Member
 
Devil_H@ck's Avatar
 
Join Date: Dec 2003
Location: Belgium
Send a message via ICQ to Devil_H@ck Send a message via AIM to Devil_H@ck Send a message via MSN to Devil_H@ck
Well, I had some fun with a toroid today...
I soldered one diode on my PCB the other way 'round. When I turned on the power to test/calibrate the output voltage I got a nice buzz and stinking smoke . Be sure to check your diodes again!
  Reply With Quote
Old 28th March 2004, 10:47 PM   #10
diyAudio Member
 
Join Date: Dec 2003
Location: At 35,000 ft
Send a message via ICQ to blackreplica Send a message via AIM to blackreplica Send a message via MSN to blackreplica Send a message via Yahoo to blackreplica
hello everyone,

Is there a way to check with a multimeter if the rectifier is spoilt? I have subjected the bridges to that buzzing/heat many times but never more than a few split seconds at a time. I never saw any smoke or heard any explosions thus far(basically from the exterior, nothing seems to be burnt)

The rectifier i am using is this one:
http://www.partsexpress.com/pe/showd...number=050-060

I have 2 of them at this point.

Just to recap, i tried to wire it the way matjans described in his post diagram but the buzz/heat persists.

Really appreciate any help!
  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
Trouble choke loading tube in regulated supply phrarod Tubes / Valves 19 14th June 2009 06:13 PM
TubelabSE power supply trouble wicked1 Tubelab 26 14th December 2008 07:59 PM
More GC Power Trouble rampage101 Chip Amps 1 8th April 2004 01:58 AM
Having trouble building a power supply for a phono preamp SideA Solid State 1 4th April 2003 06:34 AM


New To Site? Need Help?

All times are GMT. The time now is 01:53 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