Refinishing aluminum 075 tweeter

I'd like to diassamble 075 tweeter in order to refinish the aluminum bullet and cone. Can anyone advise a procedure that doesn't disrupt the integrity of the tweeter? Thx!

Attachment 91177

Attachment 91178

Attachment 91179

The bullet nose should just unscrew (counter-clockwise) without much effort, but it has been on there perhaps half a century so you might need to grab it with one of those rubber can-opening helpers. I'd probably try some (brass) "steel" wool and see what you get. Obviously you won't' want to mess with those original red-wax seals. Often the Japanese restorers will polish the aluminum to a chrome-like shine or even plate them in gold. I'm assuming you just want them to look like they looked when new.

Phil,

That's bad advice to give to "hifi".

Unscrewing that central phase plug will twist//grind the base of the phase-plug against the inner//central clamping ring of the diaphragm and then distort the working portion of the diaphragm ( ultimately ruining it's performance ).

Complete ( careful ) disassembly is required here all with the attendant loss of value ( due to losing the red wax-plugs ) just to gain a more pleasing look.

:)

Here's what happens with twisting;

https://www.audioheritage.org/vbulle...1&d=1427281776

https://www.audioheritage.org/vbulle...3&d=1427234854

Earl, thanks for the advice and glad I didn't jump in! What would you suggest for a refinishing procedure without diassambley?

My advice is to leave it as is.

:)

Quote:

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Originally Posted by Earl K

Phil,

That's bad advice to give to "hifi".

Unscrewing that central phase plug will twist//grind the base of the phase-plug against the inner//central clamping ring of the diaphragm and then distort the working portion of the diaphragm ( ultimately ruining it's performance ).

Complete ( careful ) disassembly is required here all with the attendant loss of value ( due to losing the red wax-plugs ) just to gain a more pleasing look.

:)

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Thanks for the correction. But it begs the question: What is the original order of assembly? Or is it meant never to come apart without diaphragm replacement?

Quote:

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Originally Posted by BMWCCA

Thanks for the correction. But it begs the question: What is the original order of assembly? Or is it meant never to come apart without diaphragm replacement?

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[A] Remove the rear decal hiding the through-bolt that holds the phase plug in-place ( here; the "phase-plug" = bullet-shaped nose-cone .

[B] Remove the outer horn next ( this means, removing the 4x wax seals ).

[C] While firmly holding the phase-plug to prevent it from turning ) remove the central screw/bolt.

[D] Carefully lift phase-plug ( straight-off ) of the central clamping-ring of the diaphragm

[E] Diaphragm is now ready to be un-soldered

:)

Quote:

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Originally Posted by Earl K

[A] Remove the rear decal hiding the through-bolt that holds the phase plug in-place ( here; the "phase-plug" = bullet-shaped nose-cone .

[B] Remove the outer horn next ( this means, removing the 4x wax seals ).

[C] While firmly holding the phase-plug to prevent it from turning ) remove the central screw/bolt.

[D] Carefully lift phase-plug ( straight-off ) of the central clamping-ring of the diaphragm

[E] Diaphragm is now ready to be un-soldered

:)

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Thanks again. Once more JBL hides the goodies under a foil-cal!
Mine are about 65-years-old. I think I'll leave them be.