Isolation Transformer

[HarryHaller]

Isolation transformer made from 175 VA Signal Transformers wired back to back by connecting secondaries in parallel . Spilt bobbin construction, and capacitive coupling of secondary windings to ground, makes for very good common mode noise rejection. About $55 worth of materials thanks to surplus shopping.

http://www.signaltransformer.com/signal/products/pdfs/page_08.pdf

H.H.

 

[fcel]

Using the chop board ($2?) as the chassis and utilizing the handle for easy transporting of the Isolution Transformer ... I like it! I'm downloading the pdf file now.

 

[Peter Daniel]

Those lexan cubes are pretty popular in your projects. Are you getting them ready or you glue them yourself Harry?

 

[HarryHaller]

Plastic cubes

No glue. Screws and nuts. The one I used here is a display case for a golf ball. Plastic is easy to drill and machine and does not require extra insulators.It also has low and well damped mechanical resonance. I was a good machinist like someone here.......

H.H.

 

[rtirion]

I am sorry but I am not really sure I understand the term "spilt bobbin construction".
Does it mean that both paralleled secondaries are "floating"?
And, are there no ill effects when the transformers are that closely mounted?

 

[mrfeedback]

Hello rtirion,
Split-bobbin transformer means that the primary and secondary windings are totally seperated in compartments, as opposed to older types where the windings are on top of each other.
Split bobbin transformers are pretty much standard equipment in modern commercial equipment.
Like Harry says the benifits are low capacitive coupling.
Also pretty much infinite winding to winding breakdown voltage.
See the PDF link that Harry posted.

Eric.

 

[mrfeedback]

Bootleg Breadboard.

Hi Harry,
What sonic benefits are you getting with this arrangement ?.
Is pinching your wifes breadboard worth this ?.

Regards, Eric.

 

[rtirion]

Thanks for the split bobbin explanation

 

[mrfeedback]

No worries.

 

[rtirion]

I have just build one using two 225va toroids. (that was all i had)
It works very nice. I did put it between the wall outlet and my CD player and amplfier. Seems the sound is cleaner, and more relaxed than without.

Thanks H.H.