Output Transformer Power Rating Question - 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 27th February 2012, 08:23 PM   #1
mfaughn is offline mfaughn  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Sylva, NC
Question Output Transformer Power Rating Question

What does the power rating of an output transformer mean?

I've read about people extracting more power from output transformers than their erstwhile ratings would indicate.

Is this safe?

What are the results on sonics?

How much is too much?

Supposing I have some output transformers that are being used in an amplifier that is capable of more power than the transformers are rated for BUT I never turn up the gain so high as to actually produce more output power than the transformers are rated for. What then?

Do the answers vary depending on whether the amplifier is class A or A/B?
  Reply With Quote
Old 27th February 2012, 10:25 PM   #2
diyAudio Member
 
trobbins's Avatar
 
Join Date: Feb 2009
Location: Melbourne, Oz
Depends entirely if you're a guitarist - using 60W OT's for 100W overdrive is often a real pleasure.
  Reply With Quote
Old 27th February 2012, 10:36 PM   #3
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Issues include heating, DC core saturation (for SE), primary inductance, insulation quality. As trobbins says, it also depends on whether you are making an instrument or a reproducer.
  Reply With Quote
Old 27th February 2012, 10:45 PM   #4
mfaughn is offline mfaughn  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Sylva, NC
Well, I'm interested in both but my immediate interest is in reproducers.
  Reply With Quote
Old 28th February 2012, 12:09 AM   #5
diyAudio Member
 
HollowState's Avatar
 
Join Date: Aug 2006
Location: Taxland, New Jersey
Quote:
Originally Posted by mfaughn View Post
What does the power rating of an output transformer mean?
It refers the maximum power output level it can pass over it's entire frequency range without overload distortion. The lowest octave is the main limiting factor.

Quote:
I've read about people extracting more power from output transformers than their erstwhile ratings would indicate.
This is true, but there are restrictions and/or consequences. If you do not need the lowest octave (30-60Hz), then you can pass more wattage then it's rating. As an example, I use 60 watt OPTs with PP 6550's and because I crossover at 60Hz before the amplifier, I can easily push 100 watts through it. And that's a nice clean sine wave, not simply music. The lower frequencies would overload and distort at that level.

Quote:
Is this safe?
Within the constraints noted above it is safe for normal program material. I would not consider steady state high power waveforms (sine waves) to be safe for the transformer's useful life.

Quote:
What are the results on sonics?
For a quality transformer, not much provided you stay within the limited frequency range.

Quote:
How much is too much?
This is dependent on the individual transformer. But I would speculate no more then 50% above maximum above 60Hz.

Quote:
Supposing I have some output transformers that are being used in an amplifier that is capable of more power than the transformers are rated for BUT I never turn up the gain so high as to actually produce more output power than the transformers are rated for. What then?
No sweat, provided you keep the power level below maximum rating. You'll hear the distortion when it goes above.

Quote:
Do the answers vary depending on whether the amplifier is class A or A/B?
Generally no. Power is power regardess of the class of operation.
__________________
"It is hard to imagine a more stupid or more dangerous way of making decisions than by putting those decisions in the hands of people who pay no price for being wrong." ~Thomas Sowell
  Reply With Quote
Old 28th February 2012, 12:15 AM   #6
mfaughn is offline mfaughn  United States
diyAudio Member
 
Join Date: Nov 2009
Location: Sylva, NC
Thanks HollowState. That was just what I was looking for
  Reply With Quote
Old 28th February 2012, 09:12 AM   #7
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
frequency response and power levels are inter-related:

Click the image to open in full size.
__________________
the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....
  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
output transformer power rating mr2racer Tubes / Valves 8 19th September 2011 09:16 AM
Power transformer rating rsumperl Tubes / Valves 12 1st October 2010 02:54 PM
Transformer primary rating question gary h Tubes / Valves 2 26th June 2008 06:24 PM
Question: Toroidal transformer rating siuguyguy Power Supplies 4 26th September 2006 02:08 AM
Aleph 2 transformer power rating lawka Pass Labs 17 16th January 2004 08:26 AM


New To Site? Need Help?

All times are GMT. The time now is 06:33 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