Simple basic question quick

guitvinny · 8th October 2006, 11:41 PM

Ive build my amplifier, do I have to isolate the output tranny ? because when I dont do it I got a short on my power sup... and when I isolate them from the chassi it work perfecly...

thank

Wavebourn · 9th October 2006, 12:23 AM

Primary is shorted. I would not use such a transformer.

HollowState · 9th October 2006, 12:43 AM

After reading your question, my first thought was that you may have a shorted transformer. Specifically a short of the primary to the core or possibly to the secondary, assuming the secondary common is grounded.

On second reading you mention isolating "them" meaning two (2). Is this a stereo amp, and do both transformers cause a short? If so, perhaps you have made a wiring error. What are we dealing with here? Push-Pull or singel ended? What transformers are you using and where did they come from?

Output transformers should never need isolation from the chassis or ground.

Victor

guitvinny · 9th October 2006, 12:46 PM

Only one made this, its a 2 channel push pull, those tranny came from edcore`s custom shop...hopefully I`ve buy 3 tranny instead of only 2... maybe should I try the other one next week

Sheldon · 9th October 2006, 02:56 PM

A few simple measurements with a DMM should tell you if you have a short and where it is. Measure primary to core, primary to secondary, and secondary to core. You should see an open circuit in all cases.

It might be possible that a shorted primary will not show up without high voltage on the core. That can be measured (very carefully) by checking the voltage from core to ground with the transformer isloated from the chassis and power on. Before you do that, though, you might remove the bells and check that you don't have an obviously pinched wire.

Sheldon

8th October 2006, 11:41 PM	#1
guitvinny diyAudio Member Join Date: Nov 2005 Location: Québec	Simple basic question quick Ive build my amplifier, do I have to isolate the output tranny ? because when I dont do it I got a short on my power sup... and when I isolate them from the chassi it work perfecly... thank

9th October 2006, 12:23 AM	#2
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Primary is shorted. I would not use such a transformer. __________________ The devil is not so terrible as his mathematical model! Wavebourn: We Create Creativity!

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Quick Amp6-Basic Question	revans	Class D	2	2nd August 2008 04:12 AM
simple and quick question	rinx	Multi-Way	6	20th March 2008 03:13 PM
A few simple questions about basic TL's.	O_ROD	Full Range	21	8th February 2007 11:08 PM
The Need For a New Quick Simple Project...	Rino odorico	Digital Source	4	2nd September 2003 07:22 PM
quick and simple question	McBain	Solid State	3	16th August 2002 05:38 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

9th October 2006, 12:43 AM	#3
HollowState diyAudio Member Join Date: Aug 2006 Location: Taxland, New Jersey	After reading your question, my first thought was that you may have a shorted transformer. Specifically a short of the primary to the core or possibly to the secondary, assuming the secondary common is grounded. On second reading you mention isolating "them" meaning two (2). Is this a stereo amp, and do both transformers cause a short? If so, perhaps you have made a wiring error. What are we dealing with here? Push-Pull or singel ended? What transformers are you using and where did they come from? Output transformers should never need isolation from the chassis or ground. Victor

9th October 2006, 12:46 PM	#4
guitvinny diyAudio Member Join Date: Nov 2005 Location: Québec	Only one made this, its a 2 channel push pull, those tranny came from edcore`s custom shop...hopefully I`ve buy 3 tranny instead of only 2... maybe should I try the other one next week

9th October 2006, 02:56 PM	#5
Sheldon diyAudio Member Join Date: Dec 2003 Location: San Diego	A few simple measurements with a DMM should tell you if you have a short and where it is. Measure primary to core, primary to secondary, and secondary to core. You should see an open circuit in all cases. It might be possible that a shorted primary will not show up without high voltage on the core. That can be measured (very carefully) by checking the voltage from core to ground with the transformer isloated from the chassis and power on. Before you do that, though, you might remove the bells and check that you don't have an obviously pinched wire. Sheldon

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)