Output transformer Question

keithgreenhalgh · 28th July 2008, 06:06 AM

The amp is a Leak(British company)Amplifier from about 1960.See Schematic.I am restoring this but when I measured the output resistance this is the readings I got.First don't the reading seem low for a output transformer and second,why is the center tap not equally resistance from the ends. I thought at first that the output transformers were bad but they are both identical.Why is't the center tap in the middle of the transformer?

Tweeker · 28th July 2008, 06:12 AM

On a cheaper (less interleaved) transformer, it can simply be because the turns get longer as you get further from the core. Each side has the same number of turns, but the ones further from the bobbin are longer and thus have higher resistance.

I do not see a schematic.

keithgreenhalgh · 28th July 2008, 06:16 AM

I can't seem to upload the schematic. So you are saying that the coil is really tapped in the middle? Also isn't 100 ohms low for an output transformer.

keithgreenhalgh · 28th July 2008, 06:19 AM

I try again with schematic

sorenj07 · 28th July 2008, 06:20 AM

http://imageshack.us/

Copy the code from the box marked "Thumbnail for forums (1)" into your post, and the picture will appear.

keithgreenhalgh · 28th July 2008, 06:29 AM

[IMG]http://[/IMG] I,m trying to upload from my computer

keithgreenhalgh · 28th July 2008, 06:32 AM

hope its here now its saying the schematic is too big.

analog_sa · 28th July 2008, 06:49 AM

The transformer seems perfect.

keithgreenhalgh · 28th July 2008, 06:51 AM

OK thanks

ocha · 2nd August 2008, 02:34 PM

I have a pair of OPT (picture)

I have some questions:

-Which tube can be used with this OPT?
-How to use this OPT with SE and PP?
Please give me some schematics (if possible)

Thanks a lot.

28th July 2008, 06:06 AM	#1
keithgreenhalgh diyAudio Member Join Date: Feb 2007 Location: victoria canada	Output transformer Question The amp is a Leak(British company)Amplifier from about 1960.See Schematic.I am restoring this but when I measured the output resistance this is the readings I got.First don't the reading seem low for a output transformer and second,why is the center tap not equally resistance from the ends. I thought at first that the output transformers were bad but they are both identical.Why is't the center tap in the middle of the transformer?

28th July 2008, 06:12 AM	#2
Tweeker diyAudio Member Join Date: Dec 2004 Location: Cincinnati, Ohio	On a cheaper (less interleaved) transformer, it can simply be because the turns get longer as you get further from the core. Each side has the same number of turns, but the ones further from the bobbin are longer and thus have higher resistance. I do not see a schematic. __________________ Be sure your foil hat has a good low impedance ground.

2nd August 2008, 02:34 PM	#10
ocha diyAudio Member Join Date: Jul 2005 Location: Hanoi	I have a pair of OPT but I have no clue... I have a pair of OPT (picture) I have some questions: -Which tube can be used with this OPT? -How to use this OPT with SE and PP? Please give me some schematics (if possible) Thanks a lot.

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
Se output transformer question	nhuwar	Tubes / Valves	5	4th March 2008 02:06 PM
Output Transformer Question?	Cloth Ears	Tubes / Valves	9	3rd April 2007 04:37 PM
1:1 output transformer question	Tyimo	Solid State	31	16th January 2007 01:14 PM
Output Transformer Question	316a	Tubes / Valves	3	14th June 2004 02:58 PM

28th July 2008, 06:16 AM	#3
keithgreenhalgh diyAudio Member Join Date: Feb 2007 Location: victoria canada	I can't seem to upload the schematic. So you are saying that the coil is really tapped in the middle? Also isn't 100 ohms low for an output transformer.

28th July 2008, 06:19 AM	#4
keithgreenhalgh diyAudio Member Join Date: Feb 2007 Location: victoria canada	I try again with schematic

28th July 2008, 06:20 AM	#5
sorenj07 diyAudio Member Join Date: May 2006	http://imageshack.us/ Copy the code from the box marked "Thumbnail for forums (1)" into your post, and the picture will appear.

28th July 2008, 06:32 AM	#7
keithgreenhalgh diyAudio Member Join Date: Feb 2007 Location: victoria canada	hope its here now its saying the schematic is too big.

28th July 2008, 06:49 AM	#8
analog_sa diyAudio Member Join Date: Aug 2002 Location: Sofia	The transformer seems perfect.

28th July 2008, 06:51 AM	#9
keithgreenhalgh diyAudio Member Join Date: Feb 2007 Location: victoria canada	OK thanks

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

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