Output Transformer Windings in parallel - 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 30th January 2015, 03:37 PM   #1
apnneto is offline apnneto  Brazil
diyAudio Member
 
Join Date: Dec 2011
Default Output Transformer Windings in parallel

When the secondary are connected in parallel, as in the drawing below, which is the final impedance? I need this information to adjust the feed back loop.

Any help is welcome.
Attached Images
File Type: png TVA1.PNG (38.6 KB, 272 views)
  Reply With Quote
Old 30th January 2015, 04:02 PM   #2
diyAudio Member
 
ruffrecords's Avatar
 
Join Date: Jun 2007
Location: Holt, Norfolk
It will be one quarter of what they were in series.

Cheers

Ian
  Reply With Quote
Old 30th January 2015, 04:13 PM   #3
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
That OT diagram looks a lot like the setup that Hammond uses (or used to on older OTs). An 8 Ohm winding with a 4 Ohm tap. Connecting the other 4 Ohm winding across the 0 and 4 Ohm tap just increases the current output capability, still 4 Ohm across the 0 to 4 tap and 8 Ohm across the 0 to 8 taps.

You connect the extra 4 Ohm winding in series with the 0 to 4 Ohm taps to get 16 Ohm out from the series combo. Looks like the diagram has the extra winding connected across the wrong taps. (will smoke the OT in that case since the 4 to 8 Ohm taps are actually a 2 Ohm winding, not 4)
__________________
If it isn't broken, take it apart and mod it.

Last edited by smoking-amp; 30th January 2015 at 04:17 PM.
  Reply With Quote
Old 30th January 2015, 04:21 PM   #4
apnneto is offline apnneto  Brazil
diyAudio Member
 
Join Date: Dec 2011
Quote:
Originally Posted by apnneto View Post
When the secondary are connected in parallel, as in the drawing below, which is the final impedance? I need this information to adjust the feed back loop.

Any help is welcome.
Ok, Thank you ,

but is this true if the windings impedance were with different values? In this case, 4-8 is in parallel with 0-16.
  Reply With Quote
Old 30th January 2015, 04:25 PM   #5
diyAudio Member
 
jazbo8's Avatar
 
Join Date: Jan 2011
Location: In Transient
"0-16" is actually another 4R winding as smoking-amp said, here is the wiring diagram for the Hammond OPT, which should be similar to the one used in TVA-1.

Click the image to open in full size.
  Reply With Quote
Old 30th January 2015, 04:27 PM   #6
apnneto is offline apnneto  Brazil
diyAudio Member
 
Join Date: Dec 2011
Quote:
Originally Posted by smoking-amp View Post
That OT diagram looks a lot like the setup that Hammond uses (or used to on older OTs). ...
Thank you, but this is Michaelson & Austin power amplifier and the drawing is ok.

Unfortunately, I don't have a unit to do some measurements. It uses half of 8 ohm (winding) to connect in parallel with 0-16 windings.
  Reply With Quote
Old 30th January 2015, 04:29 PM   #7
apnneto is offline apnneto  Brazil
diyAudio Member
 
Join Date: Dec 2011
Quote:
Originally Posted by jazbo8 View Post
"0-16" is actually another 4R winding as smoking-amp said, here is the wiring diagram for the Hammond OPT, which should be similar to the one used in TVA-1.

Click the image to open in full size.
Got it. Now makes sense. Thank you.
  Reply With Quote
Old 30th January 2015, 05:03 PM   #8
diyAudio Member
 
Tom Bavis's Avatar
 
Join Date: Jun 2002
Location: Macedon NY
It's labeled in a misleading way - windings need to the same number of turns to be connected in parallel, or it will be effectively a number of shorted turns.
  Reply With Quote
Old 30th January 2015, 05:18 PM   #9
apnneto is offline apnneto  Brazil
diyAudio Member
 
Join Date: Dec 2011
Quote:
Originally Posted by Tom Bavis View Post
It's labeled in a misleading way - windings need to the same number of turns to be connected in parallel, or it will be effectively a number of shorted turns.
That's why it makes sense. Two windings of 4r in parallel.

Thank you for confirm that.
  Reply With Quote
Old 30th January 2015, 05:39 PM   #10
apnneto is offline apnneto  Brazil
diyAudio Member
 
Join Date: Dec 2011
That interesting the label on the OT, as shown in the picture below ... Why that

Maybe to avoid clone the power amp?
Attached Images
File Type: png OT_TVA1.PNG (358.8 KB, 218 views)
  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
Parallel transformer output rodrigosalvati Analog Line Level 26 22nd June 2014 09:46 PM
Parallel Output transformer question deicide67 Tubes / Valves 5 19th November 2012 09:47 PM
FS: 2 EXO-050 SINGLE-ENDED PARALLEL FEED (PARAFEED) OUTPUT TRANSFORMER NICKEL LAMS makingmoney Swap Meet 1 21st February 2012 02:59 PM
FS: ONE EXO-050 SINGLE-ENDED PARALLEL FEED (PARAFEED) OUTPUT TRANSFORMER makingmoney Swap Meet 0 18th February 2012 08:09 PM
Parallel secondary windings jlm Pass Labs 6 27th March 2004 10:39 AM


New To Site? Need Help?

All times are GMT. The time now is 03:19 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2