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"dual" copper wire in transformer replacement.

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Pommaq

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As the title states. I'm trying to rewind a copper coil but noticed that the wire appears to be "dual" (see picture). I'm trying to find a replacement wiring and is wondering whether or not I should keep this in mind when purchasing new copper wire for it.
Also: I can't seem to find any similar copper wire, can I just replace it with a "mono" wire?
Picture:
 

alec_t

Well-Known Member
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Are the two wires of a pair insulated from each other?
What size thing are we looking at?
 

JonSea

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It's probably a bifilar winding. Start with a length of magnet wire, bend it in half at the center, and wind the coil with the parallel strands.
 

Pommaq

New Member
Thanks for the response, I don't think its a bifilar winding as both of the wires start and end at the same spot, being soldered together. So I would count them as not being insulated from each other, might aswell think of them as one wire.
Picture attempting to explain (Note: each line is supposed to represent one wire, except for the "circuit board":
 

JonSea

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Do both soldered connections go somewhere in the circuit or is one end just an anchor point?
 

Ylli

Active Member
Is this in an RF circuit? Using the two wires like that would increase the 'Q' of the coil.
 

Pommaq

New Member
Is this in an RF circuit? Using the two wires like that would increase the 'Q' of the coil.
Made a quick google what RF is (I'm relatively new to electronics) and I would say no. (If RF is used to transmit wireless signals.)
And I'm dumb. It's a transformer as there is a chunk of metal around it. Question still stands however.
 

Ylli

Active Member
More information as to how it is being used would be helpful. What does it look like with the 'chunk of metal' around it? What piece of equipment is it out of?
 

Pommaq

New Member
More information as to how it is being used would be helpful. What does it look like with the 'chunk of metal' around it? What piece of equipment is it out of?
Problem is, I'm not really sure what it does, it seems relatable to audio as there is another transformer stepping down the 230V. (and this is placed after the AC-DC conversion) . It looks nearly identical to this transformer:
http://litone.manufacturer.globalso...rmer/1033790969/EE-Type-Power-Transformer.htm

It's pulled from a Fender guitar amp (Champion 100). They were kind enough to give me a wiring diagram altough I'm not permitted to upload it, so sadly I can't upload it. However it's symbol looks like this (Note the slightly faded line, it's intentional):

Pins (I suppose that is what the numbers are for, there are spots for 12 pins total, altough there is only 11 pins on it.) Number 10, 8 and 7 are connected to ground. 8 being the iron chunk/core?
 

crutschow

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I don't think its a bifilar winding as both of the wires start and end at the same spot, being soldered together.
That's how bifilar windings work.
They consist of two or more wires in parallel that are tied together at the ends.
The purpose of this is to reduce skin effect wire resistance at higher frequencies.

Here's a calculator for that effect.
For example, it shows that at a frequency of 20kHz, you should use wire no larger than 18AWG to avoid the reduction in the wire resistance due to the skin effect.
This indicates that, since this is from a guitar amp where the signal frequencies of interest are not higher than 20kHz, using a bifilar winding is likely overkill.
 

crutschow

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If it's part of a switching supply which typically operate at above 20kHz, then that would explain the bifilar winding.
For example, at 100kHz, the skin effect is noticeable on wires larger than 25AWG.
 

Pommaq

New Member
Alright, I take it I will need to find the "dual" wire then. (As I still intend to rewind it.). Thanks for the help!
 

Pommaq

New Member
Your "dual wire" question was answered long ago.
True, and thanks for that. :)
Tough I was wondering if I could simply replace it with a single wire, which is now answered. altough I guess you sorta answered it from the get-go aswell.
 

crutschow

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popper

New Member
You can buy bifilar wire but if you want the amp to actually work, buy the thing from Fender. SMTP coil, if you screw up, you can buy another amp.
 
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