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AR 7 tweeter wiring


b_sdaddy

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Apologies but it's my first venture into all things AR...

have myself a lovely pair of AR7's which I have restored to their former glory. To be honest nothing wrong save re-foaming the woofers and completely renovating the cabinets/cloth.

They sound lovely.

Anway to the tweeter problem. (apologies again, I'm a novice)

being front fed, the wiring has been damaged, but hopefully not beyond repair? The wire from the tweeter is extremely 'hair' thin which is secured/shielded to the tweeter cone with an adhesive bead. once this wire reaches the outer edge of the tweeter plate, it seems to be whiped around a length of braided copper wire (as used to the rear of the woofer)

PROBLEM; on one of the tweeters, the braided wire has come away & left a 5mm stump of the extremely hair thin wire. this is again, only 5mm from where it originates on the dome perimeter.

Q: can a-nother length of braided wire be attached? possibly with conductive adhesive given that there's so little available to work with? it's so close to the point of origin.

I have removed the old,brittle black, insulation tape that originally insulated the bare wire. Would prefer to 'update' with an insulated wire (shock horror for the purists,sorry)

can x2 brand new contacts be estasblished, or do I have too splice/solder/glue new braided wires onto the available thin wires that remain?

I assume nothing can be done to convert to a conventional rear connection? (again, sorry to the purists)

apologies, I'm a novice here and anything you can supply me with would be most appreciated,

kind regards from Belgium

ps. at this point have not bothered with photos, but can if helpful.

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Apologies but it's my first venture into all things AR...

Welcome to CSP and PLEASE don't apologize for asking questions. That's one of the main reasons we get together here. I for one knew nothing at all about classic speaker restoration when I joined a few years back. That's why I joined! So again--welcome to this club of enthusiasts.

Your specific question has been raised before, so let's wait for someone who has actually worked on those tinsel leads to reply. Carl wrote a helpful, illustrated how-to pdf file that is in the Allison section:

http://www.classicspeakerpages.net/IP.Boar...7&hl=tinsel

And here is a comment from Roy:

If you need to extend the original (copper) tinsel wire of an old tweeter, a few strands of speaker wire twisted together can be soldered to it. The small gauge wire works just fine for the very short runs required to complete the connections. Efficiency is not an issue. (The hairlike wires going into the old tweeter domes are MUCH smaller than that!)

A few questions: Are your 7s woodgrain vinyl or walnut veneer? I have the walnut veneer but most seem to be vinyl. And have you recapped the speakers? MAy not be absolutely necessary, but it's pretty simple. Did you refoam the woofers yourself?

Pictures are always welcome. Size them to 100 to 200 KB so they won't be too big and slow to download.

Hope you get some answers here.

Kent

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Hi b_sdaddy and welcome to the Classic Speaker pages.

Guys, I encouraged him to come over from DIY when he spoke of his broken tweeter wire. (I feel a little guilty as I had told him it would be okay to remove the insulating tape and try a cosmetically nicer approach.)

The main question is whether this is aluminum voice coil wire or copper. What do the experts say?

Copper can be soldered to but aluminum won't solder and will need to be splice clipped or wrapped and adhered some how.

It isn't clear whether you have 5mm of wire left from the tweeter dustcap or from the tweeter perimeter. A picture would help. If only 5mm from the dustcap, you will need to be extra careful as you will only have one shot at this!

Note that you are dealing with the actual voice coil wire. A multi turn 2 layer coil is under the dust cap and its end wires come up and across the cone. The braided wire is then attached to give a tougher extension to connect to the front panel binding posts. This is a somewhat old fashioned way to do it and most modern drivers would have rear connections coming through the back chassis.

Be aware that the wire has a varnish insulation and you won't make any contact to it without either scraping or sanding off the varnish first. I would use a very sharp "exacto" knife. Let it lie on the surface of the cone and scrape lightly until you see the wire get a little shiny. You would then need to roll it slightly and take more off the other side. Carefull not to break it shorter! You can splice to any light guage multistrand wire. That secondary wire should be attached to the speaker baffle in a way that assures no stress on the voice coil wire. You might want to cover the end of the voice coil wire with a contact glue when the job is done to secure it and prevent vibration or fatigue.

Any other advice out there?

David

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dear all..

in answer to the questions; they're definately wood veneer but NOT walnut...too red. (unless this particular walnut veneer is very red)

Holland is just next door and to the foot of the paper label on the back, there's a reference to AR Holland. perhaps like our cars, they're a slightly different spec. cosmetically??

yes, I re-foamed myself having studied a few on-line tutorials... (I'm not venturing inside just yet, until I really need too)

anyway, photos show:

rear paper label with serial No.

rear of woofer with serial No.

tweeter with missing wire

rear of tweeter with serial No.

perhaps with these serial Nos. someone can establish their origin?

the photo of the front of the tweeter is here for all to see. the white arrow marks where the thin wire ends. and yes, I have scraped away the covering to expose a few presious millimeters to hopefully splice/weld/attach to.

for now,

continued thanks from belgium

post-105774-1286902723.jpg

post-105774-1286902783.jpg

post-105774-1286902810.jpg

post-105774-1286902828.jpg

post-105774-1286902851.jpg

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kent,

thanks for the info..

as you can see from the photos, it's not the tinsel that I wish to extend. It's that much thinner wire that connects to the tweeter. it has snapped off about 5mm or so from point of origin actually on the tweeter card. have scraped away some of the varnish to reveal just a few millemeters of the wire.

Q. with so little available, whiping/splicing onto a length of thicker wire seems to be out of the question..

Q. can I start again, and initiate a new contact on the tweeter.?

cheers

stephen

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Q. with so little available, whiping/splicing onto a length of thicker wire seems to be out of the question..

This is your only choice you will have to solder or clip on an extension wire. It may be best to do it in 2 parts, start with thin guage "magnet" wire to get up to the metal chassis and then connect to either braided wire, as before, or to some heavier guage wire.

Q. can I start again, and initiate a new contact on the tweeter.?

This is the only contact path available. it is the actual voice coil as it comes up from below the cone.

If you can do delicate soldering you have a chance, otherwise search Ebay for a new tweeter.

The question of copper vs. aluminum remains. Does you scraped wired have light copper color or is it colorless silver (therefore probably aluminum)?

David

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For what it's worth, the AR literature states that the 1.5" wide-dispersion domed tweeter is "essentially" the same as that used in the AR6. I don't believe that tweeter was used in any other AR speaker but maybe Ken or some other member would know.

Kent

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This is your only choice you will have to solder or clip on an extension wire. It may be best to do it in 2 parts, start with thin guage "magnet" wire to get up to the metal chassis and then connect to either braided wire, as before, or to some heavier guage wire.

This is the only contact path available. it is the actual voice coil as it comes up from below the cone.

If you can do delicate soldering you have a chance, otherwise search Ebay for a new tweeter.

The question of copper vs. aluminum remains. Does you scraped wired have light copper color or is it colorless silver (therefore probably aluminum)?

David

I have repaired a number of AR tweeters with this problem, after a couple of failed attempts along the way. It is definitely copper wire, but removing the coating and soldering the hair-like wire is not an easy task. AR only used aluminum in some earlier tweeters and mids manufactured in the 60's. The AR-6/7 tweeter is firmly in the "copper" 70's.

Unfortunately, the AR-6/7 tweeter is rather unique and very scarce. A later back-wired version used in later models is more available, but the magnet is too large for the AR-6 and 7 cabinet holes. The later version also has slightly different response characteristics.

Roy

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For what it's worth, the AR literature states that the 1.5" wide-dispersion domed tweeter is "essentially" the same as that used in the AR6. I don't believe that tweeter was used in any other AR speaker but maybe Ken or some other member would know.

Kent

I've been looking for that driver myself. According to the library literature, it's number 200005-0 used on AR-6, 7, 8 and 4xa.

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wow,

thanks all for the info. seems that plan A: 2-stage welding is my only hope.....?

having looked closely, I can confirm that the wire indeed, has a copper hint, and not a pure white appearance.

luckilly, I have an electronics enginneer who plays at weekends restoring old TV's...when I called him, I could almost hear him rubbing his hands together at the thought of this challenge...it'll be his first speaker!

upon (successful) completetion, will let you see his handy work,

kind rgds from belgium.

kent advised me of an ebay item AR6 complete which i could use for spares...at $40 could have solved the problem..

but living in Belgium, the other side of the pond..the $120+ postage was a bit price prohibitive.

cheers anyway

stephen

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For what it's worth, the AR literature states that the 1.5" wide-dispersion domed tweeter is "essentially" the same as that used in the AR6. I don't believe that tweeter was used in any other AR speaker but maybe Ken or some other member would know.

Kent

This tweeter was first used in the AR-6, then the AR-4xa, AR-7 and AR-8. Variations on the design with different mounting flange configurations but the same dome/cone shape showed up in some later two-way AR models as well.

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This tweeter was first used in the AR-6, then the AR-4xa, AR-7 and AR-8. Variations on the design with different mounting flange configurations but the same dome/cone shape showed up in some later two-way AR models as well.

I see some "AR-ax" tweets on ebay. Do you suppose they are "xa" and would be right for the 7?

Kent

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