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Old 5th July 2005, 04:42 PM   #1
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Default Pirmary over secondary in a toroid

I'm planning on ordering some custom toroids for GC (from Europe) using amorphous core.

I have here a Definitive Technlogy toroid (from Apex Jr) with primary done over the secondary windings.

I was wondering if there is any specific advantage for audio, winding transformers in this way. It definitely produces less inrush current, and the sound is very good, but does it indeed have much advatnatge (or disadvantage) over more coventional methods of transformer winding?
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Old 6th July 2005, 01:54 PM   #2
Leolabs is offline Leolabs  Malaysia
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If u r looking for a low inrush current stuff,stick to the old EI.Tell us what they talk about thier special winding method.
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Old 6th July 2005, 02:37 PM   #3
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They were probably just mistakenly made
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Old 8th July 2005, 08:18 PM   #4
Vidalgo is offline Vidalgo  Israel
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Primary, when winded over secondary, have a more resistance - that why inrush current is lower.
Such traffo need a very good outer insulation.
It must be really hard - wind thick wire first, around rectangular shape (assuming core is not so-called "R-core").
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Old 8th July 2005, 08:53 PM   #5
jleaman is offline jleaman  Belgium
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peter you should try one of these.

http://eshop.diyclub.biz/product_inf...products_id=56
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Old 8th July 2005, 09:00 PM   #6
steenoe is offline steenoe  Denmark
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Quote:
- that why inrush current is lower.
I think this is right, I have an old "donut" ,made like this! It is smoother at startup than any other torroid I have tried! I didnt initially think it was because of the windings, but this might be the answer
I am not totally confirming this, though. But what else could it be?

Steen
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Old 9th July 2005, 12:54 AM   #7
Magura is offline Magura  Denmark
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AFAIK such way of winding also brings magnetic shielding issues to the table. I have had one of those and ditched it cause it made everything around it noisy


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Old 15th September 2005, 01:24 AM   #8
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So I ordered 2 pairs of transformers: one with secondary on the outside, the other with primary over secondary, both with amorphous cores.

The one with secondary closer to the core sounds better (to me).
No issues with a noise either.

Those are 300VA units with 50% larger dia. secondary wire.
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