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AR3a Tweeter Voice Coil Wire Gauge

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Hi all,

Just took apart one of the tweeters on my AR3a Improved as it is producing very low output and the impedance is quite low - I think it is less than 0.5 ohms. I want to try to rewind the coil ! Can anybody able to give me some information on the gauge and type of wire I should be getting ? I have got nothing to lose but try.

It looks like some of the wires kind of short circuited but not quite all the way. So the tweeter is still working but very quiet.

I will attach a picture or 2 later.

Best regards,

David.

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Hello David,

The AR drawing (DRG. NO. 202029, ISS. C of 14 May 1982) reports the use of N. 38 AWG insulated copper wire for the 3/4" lambda driver voice coil. It also reports 22-24 turns in all  and a DC resistance from 3 to 3.7 ohms REF.

Taking into account that AR 3a tweeter voice coil has about 20 turns, (that is 10-20 % less than lambda driver's),  using the same wire gauge, the resulting DC resistance should be OK. 
Examining some AR 3a voice coil by a biomicroscope, I have counted about 8 and 12 turns for the outside and inside layer respectively.
 
Luigi

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Thanks Luigi,

It is something that I want to try since the original tweeter has such a low output and low impedance. It feels as if some of the wires got short circuited but can't be certain. I will still need to find some glue to fix the cone but think the glue should be quite stiff in order to produce high frequencies. If all these don't work, I may find a new diaphragm and try or get the hivi-q1r.

Best regards,

David

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I have no doubt that Chris will do a good job with my tweeters. But being a DIY guy, I would want to try it out myself first before sending them to the States side.

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Before I get the wire to rewind the tweeter coil,  I have done a bit of quick Frankenstein style on the AR3a Improved. Made a rough blanking plate to fit a pair of AR94s tweeters for testing. Low volume testing sounds ok and hope that I have destroyed anything in the process.

Please don't laugh.

 

IMG_20170404_203459.jpg

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Well, it is proving quite difficult to rewire the coil. I kind of half destroyed the paper former. I will need to find the right paper to make a new coil. But at the mean time, I replaced the coil with a new 4 ohm diaphragm. It sounds reasonably ok. Will add the inductor later but it is sounding much better than before. I will listen to them as now and think about the inductor later.

IMG_20170408_220351.jpg

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Is that the china dome?

 

what is your impression?

I have used one on a ar11.   It outputs less than the ar11 tweeter, but its not too bad.

 

 

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Hi Harry398,

 

Yes, the dome is the Chinese made.

It sounds reasonably good. Since I do not have a tweeter working to the original specs, I can't really compare. But it is far better than the old one that wasn't outputting much.

If I am adventurous enough, I would order just the coils (without the dome) and attach to the old original 3 dome. But so far I can't get any specification information out from the  seller and I will have to order a minimum of 100 units.

David.

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What type of glue did you end up using around the outside of that fabric?

 

I am actually surprised someone hasnt marketed a 3/4 dome tweeter for the ar3a.......

 

I have used the Hivi on another set of ar3a's.....and they actually arent too bad either.   Really good on bells and high freq sounds.....and not too bad on dispersion as some have said.   Overall acceptable!   Need to add the recomended coil........and actually I had better results with stock sized cap as well.....

 

keep us posted.

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8 hours ago, harry398 said:

What type of glue did you end up using around the outside of that fabric?

 

I am actually surprised someone hasnt marketed a 3/4 dome tweeter for the ar3a.......

 

I have used the Hivi on another set of ar3a's.....and they actually arent too bad either.   Really good on bells and high freq sounds.....and not too bad on dispersion as some have said.   Overall acceptable!   Need to add the recomended coil........and actually I had better results with stock sized cap as well.....

 

keep us posted.

I have pair of HiVi tweeters ready to go into my 3as.  Coil and cap included.  I just never have tried them out. Guess I should give them a go since I went to all the trouble. 

der

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The cone was from the AR3a when I destroyed the coil trying to fix it. The coil was from a Chinese supplier.

There is still lots to experiment if I want to put it back to the original tweeter body !

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I never saw a ar3a dome that dark in color.

Looks like a later model dome, like the ar11., but the ar 11 had a little fabric overhang which you glue to the assembly.   I guess that "improved" model could be slightly different, and I do notice its more like the late model ar3a with wiring on the backside.

I wonder how you will affix that dome........kinda like the factory did with some type of snot glue?

 

yes, I also tried the china dome out....its not too bad, but it does output less than the factory ar11 tweeter and the ar58bxi tweeter.   I havent done enough testing to see if its as good (even though the output is less), I have been to sidetracked and busy

I am enjoying your progress, keep it coming.

 

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I'm also interested in this. I have a number of tweeters, 48ls and 28s spring to mind which I would like to re-coil.

Also in the UK. If you can provide any hints in removing the old wire and applying the new wire that would be great.

I'm also pondering a number of woofers. So far only found the correct spec wire for those.

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