Blowing output transformer

pazo · 23rd April 2009, 10:26 PM

Is possible destroyed output transformer of valve amplifier .
For example if you turn on aplifier without speaker. Push-pull desing with two 6L6 gc otput tubes.

DigitalJunkie · 23rd April 2009, 11:25 PM

Is it possible to fry an OPT? Yes.

Running a tube amp without a load is a bad idea because the voltage swing on the primary leads can be very high.It might arc over in the output tube(s),or arc over on the transformers primary windings and ruin the OPT.Some amps may even oscillate or show other odd behavior with no load attached.

Another potential cause of a fried OPT is over current.This might happen from running the output tubes with too much bias current,or if one (or both) of the output tubes lose bias voltage,and go 'full tilt',thus running way too much current through the OPT primary and tube(s) until finally something gives. The excessive current draw may even stress the power transformer(and the rest of the PSU) to the point of failure.

pazo · 24th April 2009, 02:21 PM

Thanks for explanation.

bigwill · 24th April 2009, 02:24 PM

B+ fuses are a very good thing

23rd April 2009, 10:26 PM	#1
pazo diyAudio Member Join Date: Jul 2008	Blowing output transformer Is possible destroyed output transformer of valve amplifier . For example if you turn on aplifier without speaker. Push-pull desing with two 6L6 gc otput tubes.

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23rd April 2009, 11:25 PM	#2
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	Is it possible to fry an OPT? Yes. Running a tube amp without a load is a bad idea because the voltage swing on the primary leads can be very high.It might arc over in the output tube(s),or arc over on the transformers primary windings and ruin the OPT.Some amps may even oscillate or show other odd behavior with no load attached. Another potential cause of a fried OPT is over current.This might happen from running the output tubes with too much bias current,or if one (or both) of the output tubes lose bias voltage,and go 'full tilt',thus running way too much current through the OPT primary and tube(s) until finally something gives. The excessive current draw may even stress the power transformer(and the rest of the PSU) to the point of failure.

24th April 2009, 02:21 PM	#3
pazo diyAudio Member Join Date: Jul 2008	Thanks for explanation.

24th April 2009, 02:24 PM	#4
bigwill General Nuisance diyAudio Member Join Date: Dec 2004 Location: UK	B+ fuses are a very good thing