online transformer info for newbies - 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 17th June 2007, 05:35 PM   #1
diyAudio Member
 
Join Date: Dec 2003
Location: earth
Default online transformer info for newbies

In response to posts looking for info about transformers, I thought i would bring all these together!!

http://www.valveheart.com/theory/transformer.html

http://www.geofex.com/Article_Folde...des/xformer.htm

http://members.tripod.com/richard98...former_math.htm

http://www.turneraudio.com.au/output-trans-theory.html

http://europa.spaceports.com/~fishbake/ot1/ot.htm

http://www.magnequest.com/mq_magnetics.htm

all sorts of info. in the MQ forum, too, do some searching

Feel free to add your own!!

May make sense to make this a sticky as there are all sorts of questions that crop up.
  Reply With Quote
Old 17th June 2007, 06:17 PM   #2
diyAudio Member
 
Join Date: Dec 2003
Location: earth
http://members.tripod.com/richard984...ormer_math.htm

http://www.geofex.com/Article_Folder...es/xformer.htm
  Reply With Quote
Old 20th June 2007, 01:38 AM   #3
jnb is offline jnb  Australia
diyAudio Member
 
Join Date: Dec 2006
Quote:
Originally posted by Mike LaFevre
[once you remove the dc current from the primary of the OT (either SE or PP) then the copper current density is made much better because you don't have the heating effect (and I squared R losses) that accrue from the DC being added vectorially to the AC signal current. Or, in plainer english, the primary copper circuit (say it were wound with a 31 gauge wire) will appear effectively as though it were a larger guage wire once you remove the heating effects of the dc supply current.
How is this so?
  Reply With Quote
Old 20th June 2007, 10:16 AM   #4
diyAudio Member
 
Join Date: Dec 2003
Location: earth
hmmm, not sure, I am sure tho that its talking about parallel feed, in both series feed cases with se and pp, you have the dc flowing : I think in push pull, even tho its supposed to cancel magnetically, you still get the primary heating effect of the current?

so in parallel feed, that only flows via the load choke, and the outupt tx is free just to use the ac only, thus, with only ac, effectively, you give the wire more headroom, as say, 1/2 of the capacity of the wire isn't taken up any more with dc

I think thats what he's saying, its poorly worded, as it gives the impression that the wire magically appears larger, whearas in reality it doesn't, its still got, say 31 guage capacity, but as you have taken away the dc, more is available for use by the ac signal

I really wish i understood transformers better.

Could anyone out there actually tell me the equation for the impedance calculation of the tx, ie not the ratio, or putting 8 ohms on the secondary will give 3000 ohms say.

but how you work out the Z from the inductance, load and winding resistances and all that....really struggling to put the pieces together
  Reply With Quote
Old 20th June 2007, 10:52 AM   #5
jnb is offline jnb  Australia
diyAudio Member
 
Join Date: Dec 2006
I think the measured resistance of the winding will apply to the AC regardless of what DC is upon it. I have not heard of cable having a current carrying capacity like this.

Quote:
Originally posted by lt cdr data
Could anyone out there actually tell me the equation for the impedance calculation of the tx, ie not the ratio, or putting 8 ohms on the secondary will give 3000 ohms say.

but how you work out the Z from the inductance, load and winding resistances and all that....really struggling to put the pieces together
The primary impedance (ie the reactance of the inductance) is
2 x pi x f x L.

For example, a 40H primary inductance at 20Hz.
2 x 3.142 x 20 x 40 equals approx 5,000 ohms.

DC resistance of the copper is supposed to be much lower than this so it has little effect.

If the primary has 20 times more turns than the secondary, the ratio is 20. 20 squared times an 8 ohm speaker equals 3200 ohms. That is what the speaker will look like to the primary. This needs to be less than the 5000ohms (which it is) or you need a different transformer.

BTW, I'm trying to view the valveheart websit you have recommended but it's been unavailable for some time.
  Reply With Quote
Old 20th June 2007, 11:06 AM   #6
diyAudio Member
 
Join Date: Dec 2003
Location: earth
core materials:

http://www.audioasylum.com/forums/ma...sages/102.html
  Reply With Quote
Old 20th June 2007, 11:10 AM   #7
Yvesm is offline Yvesm  France
diyAudio Member
 
Yvesm's Avatar
 
Join Date: Jul 2004
Location: Ardeche
Quote:
. . .
I really wish i understood transformers better.

Could anyone out there actually tell me the equation for the impedance calculation of the tx, ie not the ratio, or putting 8 ohms on the secondary will give 3000 ohms say.

but how you work out the Z from the inductance, load and winding resistances and all that....really struggling to put the pieces together [/B]
You can find equations anywhere.

For the most part they are used inside that :
http://www.dissident-audio.com/OPT_da/Page.html

Just a tool that helps putting pieces together.

Yves.
  Reply With Quote
Old 20th June 2007, 12:02 PM   #8
diyAudio Member
 
Join Date: Apr 2003
Location: Portland,Oregon
Blog Entries: 4
Send a message via AIM to DigitalJunkie
Some more tidbits: (scroll down a bit)
http://geek.scorpiorising.ca/articles.html

  Reply With Quote
Old 20th June 2007, 03:03 PM   #9
diyAudio Member
 
Join Date: Dec 2003
Location: earth
Bonjour Yves.

I can't seem to install that program, any ideas?
  Reply With Quote
Old 20th June 2007, 06:17 PM   #10
Yvesm is offline Yvesm  France
diyAudio Member
 
Yvesm's Avatar
 
Join Date: Jul 2004
Location: Ardeche
Quote:
Originally posted by lt cdr data
Bonjour Yves.

I can't seem to install that program, any ideas?
Damned ! That is the worst that could occur

Where does it stop ? wich message ? if any !

Of course, you browsed the readmefirst file

Try to tell me more.

Yves.
  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
DIY output transformer info site smoking-amp Tubes / Valves 9 12th April 2010 11:35 PM
Kenwood Power AMP KM-X1 transformer info space2000 Solid State 0 21st June 2008 11:08 AM
Help finding Info For Hammond Transformer dismalonyx Parts 2 11th June 2008 02:06 PM
ST-70 Power Transformer Info rudy129 Tubes / Valves 4 10th March 2007 09:23 PM
info wanted about a output transformer goudfazant Tubes / Valves 9 22nd December 2004 05:16 PM


New To Site? Need Help?

All times are GMT. The time now is 01:49 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