Hi!

I have found a pair of burnt-out vintage Celestion HF1300 tweeters, and I would like to endeavor into the task of re-winding the voice coils to get them working again. The VC "body" seems quite robust, so I have some hope to succeed. However, the copper is so damaged that I have a hard time figuring out the number of turns, or even if it is a single layer or double layer coil, etc.

One hint is the specs, I think I know that this tweeter has a specified coil inductance of 0.2mH, nominal impedance 16 ohms, dc resistance 13 ohms. If I use a coil inductance calculator, and just guess a wire diameter of 0.1mm, coil diameter of 25mm, a double layer of about 4.5 mm length, and a wire length of 6 meters I get 13 ohms and around 208uH in air.

Is this approach reasonable?

I know that an air coil will NOT have the same inductance as when the magnet iron is present, but as the speaker magnet system is not a closed magnetic circuit (only half-way) the magnet might not add too much anyway?

I think I understand that it is not the inductance itself which is the primary goal, but it is rather the motor properties which is important.

But if the resistance and inductance are in the right ballpark for the selected coil geometry, will not the motor be just about right too in the given magnet system?

Comments and suggestions are very welcome.

And YES, I have scouted eBay. Parts for 16 ohms HF1300 seems unusual and are not very likely to be found.

BN

I have found a pair of burnt-out vintage Celestion HF1300 tweeters, and I would like to endeavor into the task of re-winding the voice coils to get them working again. The VC "body" seems quite robust, so I have some hope to succeed. However, the copper is so damaged that I have a hard time figuring out the number of turns, or even if it is a single layer or double layer coil, etc.

One hint is the specs, I think I know that this tweeter has a specified coil inductance of 0.2mH, nominal impedance 16 ohms, dc resistance 13 ohms. If I use a coil inductance calculator, and just guess a wire diameter of 0.1mm, coil diameter of 25mm, a double layer of about 4.5 mm length, and a wire length of 6 meters I get 13 ohms and around 208uH in air.

Is this approach reasonable?

I know that an air coil will NOT have the same inductance as when the magnet iron is present, but as the speaker magnet system is not a closed magnetic circuit (only half-way) the magnet might not add too much anyway?

I think I understand that it is not the inductance itself which is the primary goal, but it is rather the motor properties which is important.

But if the resistance and inductance are in the right ballpark for the selected coil geometry, will not the motor be just about right too in the given magnet system?

Comments and suggestions are very welcome.

And YES, I have scouted eBay. Parts for 16 ohms HF1300 seems unusual and are not very likely to be found.

BN

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