Buzzing choke - varnish?

I have an old Stancor choke that I am using in a power supply and it is buzzing pretty badly. It does this when it is seeing 15mA and it is rated at 75mA. I want to dip it in some varnish to see if that will help. Do I have to use a special kind? Any recommendations for types or suppliers? Any DIY solutions?

Thanks,

Ben

Just about any varnish should help glue the lams together, should they be lose.

You might also try potting it in some wax., a bit messy, but it'll get into all the little spaces...

transformers can make noise when unloaded,

i wonder if you increased the load with some bleeder resistors if the buzzing would lessen,

varnish is old school, air dry epoxy is the new school,

but i like the smell of hot varnish in the morning,

it reminds me of...






transformers!


vac impregnate for best results - not!

first off, you don't have a vacuum pump,

second, it does not really need it,

preheat oven to 150 degrees and pop the choke in there,

this will make the varnish more liquidy, or vicous, depending on where your from, 


when you pull a vacuum on a transformer or choke, any air is sucked out,  except tiny air bubbles will always remain in tight places like in between the windings,

a vacuum on theses tiny bubbles makes them expand in size,

when the vacuum is released, the bubbles contract and thus pull in varnish to hard to reach areas, pretty slick eh?

however, some audio transformers leave the coils dry,

this changes the leakage C because varnish has a different constant than air,