Need tips how to repair ar-3a tweeter coil

[legopart]

after attempt to restore the tweeters 

The attempt to fix looked like that (used silicone and some useless gloe)

ends with too much glue that stock the tweeter and I burned the coil, 

 

Now I have only the  paper capes that I fixed, and the magnet

 

Need any suggestion how to restore the coil, how to fix the cap to the magnet, which material and what the right distance for the coil (the magnet form is unusual with 3 holes and the middle part lower then usual magnet by several mm).
which coil to use and how to apply it?
also, how to fix the wires on tweeter/ midrange to the top on the driver (as the newer versions of this driver)?

 

Thanks for any suggestions.

[Aadams]

6 minutes ago, legopart said:

Thanks for any suggestions.

 

Those can be repaired by RoyC.  Click on @RoyC to send him a message. 

[Giorgio AR]

legopart, in addition to the good RoyC, there is also the member Chris1this1 who reconstructs the AR3a tweeters with a final result that is both functional and aesthetic as originally while preserving the original paper domes!

[giovanni56]

On 13/8/2021 at 01:45, legopart said:

dopo il tentativo di ripristinare i tweeter 

Il tentativo di riparare sembrava così (silicone usato e qualche inutile gloe)

finisce con troppa colla che riempie il tweeter e ho bruciato la bobina, 

 

Ora ho solo i mantelli di carta che ho sistemato e il magnete

 

Ho bisogno di qualche suggerimento su come ripristinare la bobina, come fissare il cappuccio al magnete, quale materiale e quale distanza giusta per la bobina (la forma del magnete è insolita con 3 fori e la parte centrale più bassa del solito magnete di diversi mm).
quale bobina usare e come applicarla?
inoltre, come fissare i fili del tweeter/midrange alla parte superiore del driver (come le versioni più recenti di questo driver)?

 

Grazie per eventuali suggerimenti.

If you lived in Italy, I could have rebuilt them.

[Giorgio AR]

Great work Giovanni, up to now in addition to the USA repairers, you are the only one to correctly reconstruct these precious tweeters.
Gorgeous thread and great photo shoot !!

[giovanni56]

1 minute ago, Giorgio AR said:

Ottimo lavoro Giovanni, fino ad ora oltre ai riparatori USA, sei l'unico a ricostruire correttamente questi preziosi tweeter.
Bellissimo thread e ottimo servizio fotografico!!

Grazie, Giorgio, buon ferragosto! 

[Giorgio AR]

Dear Giovanni, I take this opportunity to ask if you can repair my precious AR3a tweeter which gives a value of 1 ohm when the instrument is read and does not emit a sound?
I thought of entrusting it to Chris1this1, who has a proprietary technique and brings these tweeters back to perfect efficiency!
Do you think it is better to make a pair, even if the other tweeter is OK?
Under the offending tweeter!

The non-working tweeter is on the right in the photo

Resistance value: 1.1 ohm (last photo, left tweeter with 3.2 ohm value replaced the non-working one)

[giovanni56]

1 hour ago, Giorgio AR said:

Caro Giovanni, colgo l'occasione per chiederti se puoi riparare il mio prezioso tweeter AR3a che dà un valore di 1 ohm quando lo strumento viene letto e non emette un suono?
Ho pensato di affidarlo a Chris1this1, che ha una tecnica proprietaria e riporta questi tweeter in perfetta efficienza!
Pensi che sia meglio farne una coppia, anche se l'altro tweeter va bene?
Sotto il tweeter offensivo!

Il tweeter non funzionante è a destra nella foto

Valore di resistenza: 1,1 ohm (ultima foto, tweeter sinistro con valore di 3,2 ohm ha sostituito quello non funzionante)

I have a feeling the 3.2 ohm tweeter has already been repaired, the 1.1 ohm tweeter has a shorted coil. They can be restored, but it's an awfully "heavy" job, among other things it takes a lot of time

[Giorgio AR]

Correct, there was a dent on the dome that I fixed and as you can see from the photo the soft vinyl glue that I used to isolate the three fixing dots from the environment is still drying, now and for about two years this tweeter has been working well in this AR3a.

Tweeter dent

If I do not disturb, I will send you a message because I would entrust you with the repair of the tweeter (perhaps better to be a couple? To match the 2 tweeters?)

Thank you for your patience,

Giorgio.

[giovanni56]

6 hours ago, Giorgio AR said:

Esatto, c'era un'ammaccatura sulla cupola che ho sistemato e come potete vedere dalla foto la colla vinilica morbida che ho usato per isolare i tre puntini di fissaggio dall'ambiente si sta ancora asciugando, ora e da circa due anni questo tweeter è funziona bene in questo AR3a.

ammaccatura del tweeter

Se non disturbo vi mando un messaggio perchè vi affiderei la riparazione del tweeter (forse meglio essere in coppia? Per abbinare i 2 tweeter?)

Grazie per la vostra pazienza,

Giorgio.

The tweeters are always better to be in pairs, then given the age, it would be necessary to disassemble them both, arrange them, check them to align as much as possible the T&S parameters

[legopart]

I'm not from Italy.
Any professionals that can restore the dome or send another one please send me  a private message

 

On 8/14/2021 at 12:34 PM, giovanni56 said:

If you lived in Italy, I could have rebuilt them.

do you know where can I buy another paper domes?, which voice coil can you suggest, and how do you attach the cone to the magnet (the 3 dotes and do some addition glue required)?

 

accidently smash the dome again 😢

I still want to repair this one by myself somehow,
I will order addition pair someday (its too much work to send this one abroad).

about this one:
I decided the remained caps to attach to the regular surround of 0.75" tweeter, from titanium 8ohm from aliexpress (unfortunately the soft it too much but it still good) so I attach it to the paper cone

still waiting for some repair coil and maybe for some ferrofluid 

I checked the option about some regular tweeter, my 1" pair too small. and any 0.75" have this small size (and 8ohm, I need 4ohm one )
yes, the standard tweeter today is 1" one and smaller diameter and magnet 

AR tweeter twice bigger with bigger magnet
for compare:

Found only several options on ebay for original sizes new tweeter for ar-3a with paper cone

this one  (that looks more easy for future repair if needs) https://www.ebay.com/itm/152673689795
or this one that looks more like the original https://www.ebay.com/itm/162689998131

can someone recommend one of them?

 

[giovanni56]

1 ora fa, legopart ha detto:

Non vengo dall'Italia.
Tutti i professionisti che possono ripristinare la cupola o inviarne un'altra mi mandi un messaggio privato

 

sai dove posso acquistare un'altra cupola di carta?, quale bobina mi puoi suggerire e come si collega il cono al magnete (i 3 puntini e un po' di colla aggiuntiva necessaria)?

 

rompi di nuovo accidentalmente la cupola  ?

Voglio ancora ripararlo da solo in qualche modo,
un giorno ordinerò una coppia aggiuntiva (è troppo lavoro per inviarlo all'estero).

a proposito di questo:
ho deciso che i tappi rimasti da attaccare al normale surround del tweeter da 0,75", da 8ohm in titanio da aliexpress (purtroppo il morbido è troppo ma va comunque bene) quindi lo attacco al cono di carta

sto ancora aspettando qualche bobina di riparazione e forse un po' di ferrofluido 

Ho controllato l'opzione su alcuni tweeter normali, la mia coppia da 1 "è troppo piccola e qualsiasi 0,75" ha questa dimensione piccola (e 8 ohm, ho bisogno di uno da 4 ohm)
sì, il tweeter standard oggi è 1 "uno e diametro più piccolo e magnete 

Tweeter AR due volte più grande con magnete più grande
per:

Trovate solo diverse opzioni su ebay per le dimensioni originali nuovo tweeter per ar-3a con cono di carta

questo (che sembra più facile per riparazioni future se necessario)  https://www.ebay.com/itm/152673689795
o questo che assomiglia di più all'originale  https://www.ebay.com/itm/162689998131

qualcuno può consigliarne uno?

 

MidWest MT 4121-4 4ohm. Ar3a, Ar3aMigliorato, Ar11, Ar10pigreco, Ar LST

MidWest MT 4121-8 8ohm Ar5, Ar2ax, Ar LST2. 

On Ar3a and ArLST the filter must be modified by adding an inductance of 0,105 mH in parallel to the tweeter that must be connected with inverse polarity, same thing for the 8 ohm tweeter on Ar2ax, Ar5 and Ar LST2, but with inductance of different value 0,15 mH.

[legopart]

17 minutes ago, giovanni56 said:

MidWest MT 4121-4 4ohm. Ar3a, Ar3aMigliorato, Ar11, Ar10pigreco, Ar LST

MidWest MT 4121-8 8ohm Ar5, Ar2ax, Ar LST2. 

On Ar3a and ArLST the filter must be modified by adding an inductance of 0,105 mH in parallel to the tweeter that must be connected with inverse polarity, same thing for the 8 ohm tweeter on Ar2ax, Ar5 and Ar LST2, but with inductance of different value 0,15 mH.

what the usage of the coil ?,
I will use one when I set the crossover for the speaker.

[giovanni56]

1 hour ago, legopart said:

qual è l'uso della bobina?,
ne userò una quando imposterò il crossover per l'altoparlante.

The coil is used to increase the attenuation slope of frequencies below the Fc of the tweeter's high-pass filter to avoid "breaking" the component

[legopart]

2 hours ago, giovanni56 said:

The coil is used to increase the attenuation slope of frequencies below the Fc of the tweeter's high-pass filter to avoid "breaking" the component

I plan to build some DIY crossover 2nd level.
I have umik-1 microphone to test the speakers/elements.

Can you recommend how to build the crossover for this speakers, with the potentiometers ? 

[giovanni56]

5 ore fa, legopart ha detto:

Ho intenzione di costruire un crossover fai-da-te di secondo livello.
Ho un microfono umik-1 per testare gli altoparlanti/elementi.

Mi consigliate come costruire il crossover per questi diffusori, con i potenziometri? 

 

But which speakers are you going to install those tweeters in?

 

[legopart]

  

On 8/14/2021 at 3:58 PM, Giorgio AR said:

Correct, there was a dent on the dome that I fixed and as you can see from the photo the soft vinyl glue that I used to isolate the three fixing dots from the environment is still drying, now and for about two years this tweeter has been working well in this AR3a.

Tweeter dent

If I do not disturb, I will send you a message because I would entrust you with the repair of the tweeter (perhaps better to be a couple? To match the 2 tweeters?)

Thank you for your patience,

Giorgio.

If you want to take some risk, you can try to wet it (for minute or more) with distilled water and then suck it with you're mouth

10 hours ago, giovanni56 said:

 

But which speakers are you going to install those tweeters in?

 

AR-3A,

I think to use some voice coil with 4ohm (or 8ohm) for the tweeters.
each element have 4ohm (the resistance is less, something like 3+ohm)

something like that

925 point example,

where put the potentiometer (before the crossover?) ?
why do I have to choose only between 8:3 or 10:3.4 octave (do it the best preference)?
I have only 6ohm amp, how can I mod this speaker to works with it?

[giovanni56]

5 hours ago, legopart said:

  

Se vuoi correre qualche rischio, puoi provare a bagnarlo (per un minuto o più) con acqua distillata e poi succhiarlo con la bocca

AR-3A,

Penso di usare una bobina mobile con 4ohm (o 8ohm) per i tweeter.
ogni elemento ha 4ohm (la resistenza è inferiore, qualcosa come 3+ohm)

qualcosa del genere

925 punti esempio,

dove mettere il potenziometro (prima del crossover?) ?
perché devo scegliere solo tra 8:3 o 10:3.4 ottava (fai la preferenza migliore)?
Ho solo un amplificatore da 6 ohm, come posso modificare questo altoparlante per farlo funzionare?

If you have Ar3a's, I don't understand the reason to build a new crossover filter, the Ar3a's sound good with the filter that Ar came up with, it doesn't make any sense to change it, especially in the way you outlined.

[legopart]

On 8/16/2021 at 3:23 PM, giovanni56 said:

If you have Ar3a's, I don't understand the reason to build a new crossover filter, the Ar3a's sound good with the filter that Ar came up with, it doesn't make any sense to change it, especially in the way you outlined.

I need to replace the original caps, recap the speaker.
so I plan to make a changes, measurements or even change the crossover.

 

 

what the secret behind this tweeter structure?
what is the 3 orange dots (some foam)? how they surround the dome with transparent flexible (thin glue) material ?

it not like todays caps with mesh surround that I want to apply on the cap because I cant find another method to restore it.

 

in addition the original foam material inside the tweeter dried.
(think that the same happened with the midrange and the woofer but I can't and don't want to fix it)
so I think how to repair it.
still don't know which dimensions and which foam to use
*the cracked side fixed.

 

 

Also tried to make some dome from some tv speaker paper cap,
it little bit smaller and shorter then AR-3A one, but I still can try 

the question is do it necessary, the titanium/mesh tweeters could be better,
and maybe the 8ohm tweeters is the same as 4ohm one ?

[Aadams]

Legopart

Are you in the US?  If so, there are two small, reputable service locations that can repair these tweeters.  If this were a simple mechanical repair more of us would be doing it. The tweeters are restored in matched pairs. 

This forum is dedicated to the restoration and maintenance of AR speakers with emphasis on originality.  If your intent is to rebuild yours with modified crossovers and drivers then this discussion more properly belongs in  the mods forum.

Aadams

[legopart]

2 hours ago, Aadams said:

Legopart

Are you in the US?  If so, there are two small, reputable service locations that can repair these tweeters.  If this were a simple mechanical repair more of us would be doing it. The tweeters are restored in matched pairs. 

This forum is dedicated to the restoration and maintenance of AR speakers with emphasis on originality.  If your intent is to rebuild yours with modified crossovers and drivers then this discussion more properly belongs in  the mods forum.

Aadams

Thanks!
I not from US, but I still like to contact with the stores, please send me a P.M with any information that could help to restore.
About my mode, I first plan to repair the original parts, tweeters, capacitors, potentiometers.
And then try to improve this speakers if needed.
I really like to keep the original parts from the speakers as I can. too much resources gonna waste because of this tweeter issue.   

I ordered "Vifa D19" tweeters (0.75" 8ohm much smaller then AR-3A tweeter) with some plastic adapter. but I dont think that I will use it. (I can mod it to 4ohm... but I think that the original is better even for 8ohm )