How to simulate OPT in LTspice? - 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 18th September 2008, 04:39 AM   #1
Akita is offline Akita  Malaysia
diyAudio Member
 
Join Date: Dec 2006
Location: Kuala Lumpur
Default How to simulate OPT in LTspice?

Anyone know how to simulate OPT in LTspice?

Let say 2500:8
  Reply With Quote
Old 18th September 2008, 11:08 AM   #2
diyAudio Member
 
Ty_Bower's Avatar
 
Join Date: Mar 2007
Location: Newark, DE
Try using two inductors with a K directive. According to the help file, the inductance ratio should be the same as the transformer's impedance ratio.

Click the image to open in full size.
  Reply With Quote
Old 18th September 2008, 12:53 PM   #3
oshifis is offline oshifis  Hungary
diyAudio Member
 
Join Date: Mar 2004
Location: Budapest, Hungary
Could anybody explain me what is the compatibility between PSpice and LTSpice? Can the PSpice .lib (library), .slb (schematics symbol library), .olb (OrCAD capture library) and .sch (schematics) files be used in LTSpice?
  Reply With Quote
Old 18th September 2008, 02:15 PM   #4
diyAudio Member
 
Join Date: Jul 2006
Since the engine is SPICE either way, you should be able to import the model files with some minimal work. If I remember correctly, LTSpice will let you build schematic symbols and associate its ports with a SPICE model. The code's the important part, as long as the guts are the same you should be able to make it work.
  Reply With Quote
Old 18th September 2008, 04:11 PM   #5
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
You can use most .lib files if their syntax is similar enough to ltspice's native format, however I have never had any success with importing symbols or schematics from other flavors of spice.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 18th September 2008, 11:59 PM   #6
diyAudio Member
 
Join Date: May 2005
Location: Stittsville, Ontario, Canada
Default how to model OPT in LTSpice

Quote:
Anyone know how to simulate OPT in LTspice?
Here's how I do it. I use the attached spreadsheet that I developed. Note that this is just something I whipped up for myself, I have not made it super user friendly, it assumes you know about excel, and copying and pasting etc.

It handles single ended, push pull, UL of either SE or PP type, and does multiple output taps if wanted. Its only a linear model, just gives the overall frequency you specify. It doesnt model core effects, ie saturation. A lot of the parameters such as winding resistances are just guesses on my part, put in better ones if you know them.

Brief instructions :
Go to the first worksheet ( "Main Data" ) and either select from a transformer already there, or enter specs for one of your own. For example for the 2500 to 8 ohm you asked about you may pick the HAM12627SE type. Copy and paste the data given for that into the first line of the appropriate worksheet, in this case the SE UL tab. Change the cells with tap values if you wish. The spreadssheet calculates the values, and shows two LTSpice models, one with output taps and one without. Copy and paste the one you want into your .lib file of transformers subcircuits or onto your spice schematic or however you prefer to get it into spice, and away you go.
Attached Files
File Type: zip transformer models rev1.zip (27.9 KB, 288 views)
__________________
Robert McLean
  Reply With Quote
Old 19th September 2008, 02:19 AM   #7
Akita is offline Akita  Malaysia
diyAudio Member
 
Join Date: Dec 2006
Location: Kuala Lumpur
Ty,

I get your idea. Thank.

Robert,

Great job! Thank for sharing the file.
  Reply With Quote
Old 25th June 2010, 02:16 PM   #8
diyAudio Member
 
Join Date: Jan 2003
Location: Saint Mathieu de Treviers
Hi Robert

Thanks a lot for your shared files
I use it for a short time now

But I've something to ask to you

Can you complete your spreadsheet with a CFB section

near like the UL tap in the Inductance, in fact, to simulate
far away my OPT

If it's possible and if you need real value about my OPT
Ask it , of course

I have on hand SE and PP with CFB and the way to do it is very similar
in front of UL

Best regards
  Reply With Quote
Old 25th June 2010, 04:07 PM   #9
diyAudio Member
 
Michael Koster's Avatar
 
Join Date: Jan 2008
Location: Eureka, CA
Quote:
Originally Posted by Ty_Bower View Post
..the inductance ratio should be the same as the transformer's impedance ratio.
Why?
The 2 coils are on the same core so both the impedance ratio and inductance ratio will be = turns_ratio^2 according to Faraday

Quote:
Originally Posted by Robert McLean View Post
Here's how I do it. I use the attached spreadsheet that I developed. Note that this is just something I whipped up for myself, I have not made it super user friendly, it assumes you know about excel, and copying and pasting etc.
Interesting!

It looks like you are taking the transformer frequency response spec, making some assumptions about the source and load resistance, and then deriving an estimate for inductance from those assumptions. I wonder how accurate this is going to be from manufacturer's FR specs if they don't also specify the source and load resistance conditions.

I'm not quite following the derivation of the coupling factor K. Is the leakage inductance buried in the computation somewhere? Guess I need to study it some more...

Cheers!
  Reply With Quote
Old 25th June 2010, 05:02 PM   #10
diyAudio Member
 
Join Date: May 2007
Ty_Bower is so right. Check post 1 and 2! The picture together says it all!
Winding ratio in relation to inductance or impedance is another thing that works with the formula above.
  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
Please simulate my headphone amp Nico Ras Headphone Systems 55 1st April 2008 09:01 PM
Need some help to simulate Aleph 5 guitvinny Pass Labs 7 1st January 2008 03:11 PM
Someone willing to simulate a TL for me? tubee Multi-Way 21 27th November 2007 02:25 PM
Paid to simulate steve_mak Solid State 3 8th July 2007 05:34 AM
With which can i Simulate a Zen Amplifier! bulrot Parts 6 31st May 2006 02:14 PM


New To Site? Need Help?

All times are GMT. The time now is 02:18 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