buzzing toroid transformer

[supernet]

I built my power amp some days ago and I found that his 1500VA toroid transformer start to buzzing for some time and then stops.

Could be transformer affected by AC mains?
It is normal to sound like that?


Supernet

 

[hifi]

Probobly DC on the powergrid. try connecting two power diodes in parallell butt in opposite direction paralelled with a 2200uf/35v cap. that should suffice it is very likely that something in your house or a nearby hose have something that puts a little Dc...



............I---|<---I
............I--->|---I
---------I---| |---I---------
ignore the dots


/ micke

 

[wessol]

I am having this same issue.
Where would you insert this device??

Thanks,
Shawn

 

[Peter Daniel]

There are some examples in this thread http://www.diyaudio.com/forums/showthread.php?s=&threadid=3924&highlight=schematic+explanation

 

[supernet]

No, I can´t hear any noise in my speakers, this buzzzing makes toroid winding or ferite core of transformer!!

 

[UrSv]

?

Exactly. The noise is from the transformer which is most likely due to DC on the mains AC. You might need to filter this out by following the direct advice in the reply from hifi or carefully reading the link provided by Peter. All suggestions so far have given you the answer to your question.

Wessol, read the thread Peter gave and suddenly it will become clear...it goes in series with the primary of the transformer.

/UrSv

 

[tiefbassuebertr]

in this case this thread could be of interest:
http://www.diyaudio.com/forums/soli...t-buzzing-toroid-transformers-what-right.html

 

[jemswillam]

Overloading the transformer or the presence of a small DC offset on your mains could be contributing to the mechanical noise.

Toroidal transformers seem to be the most prone to mechanical noise. A few EI transformers from Hammond that I have used also buzz. So far the few Edcor transformers I have used have been good.

Are the transformers running hot?