Isolation Transformer

HarryHaller · 4th August 2002, 05:32 PM

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/sig...fs/page_08.pdf

H.H.

fcel · 4th August 2002, 05:55 PM

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 · 4th August 2002, 06:00 PM

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

HarryHaller · 4th August 2002, 06:47 PM

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 · 4th August 2002, 11:08 PM

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 · 5th August 2002, 01:53 AM

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 · 5th August 2002, 02:04 AM

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

Regards, Eric.

rtirion · 5th August 2002, 09:12 AM

Thanks for the split bobbin explanation

mrfeedback · 5th August 2002, 11:14 AM

No worries.

rtirion · 5th August 2002, 12:30 PM

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.

4th August 2002, 06:00 PM	#3
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	Those lexan cubes are pretty popular in your projects. Are you getting them ready or you glue them yourself Harry? __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

4th August 2002, 06:47 PM	#4
HarryHaller Banned Join Date: Feb 2002 Location: Dallas,Texas	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.

5th August 2002, 02:04 AM	#7
mrfeedback diyAudio Member Join Date: Feb 2002 Location: Perth, Australia.	Bootleg Breadboard. Hi Harry, What sonic benefits are you getting with this arrangement ?. Is pinching your wifes breadboard worth this ?. Regards, Eric.

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4th August 2002, 05:55 PM	#2
fcel diyAudio Member Join Date: Sep 2001 Location: LA County	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.

4th August 2002, 11:08 PM	#5
rtirion diyAudio Member Join Date: Nov 2000	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?

5th August 2002, 01:53 AM	#6
mrfeedback diyAudio Member Join Date: Feb 2002 Location: Perth, Australia.	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.

5th August 2002, 09:12 AM	#8
rtirion diyAudio Member Join Date: Nov 2000	Thanks for the split bobbin explanation

5th August 2002, 11:14 AM	#9
mrfeedback diyAudio Member Join Date: Feb 2002 Location: Perth, Australia.	No worries.

5th August 2002, 12:30 PM	#10
rtirion diyAudio Member Join Date: Nov 2000	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.

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