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Help me resurrect my AR-90s

So, I pulled my AR90s out after many years of storage and it looks like the woofers as well as the surround need to be replaced.

My dad bought these back in England in the late 70s for $350 for the pair..."the only time I ever bounced a check he says!" Anyway, he gave them to me in 1997 when I joined the Air Force and I've drug them all over the world from Maine to Pennsylvania to Colorado to Italy to Alaska and now back to Colorado. I haven't used them for over 10 years. I've recently gotten back into vinyl records and I'm wanting to set up as system with the old AR-90s.

Where can I find replacement woofers that won't change the factory sound? Anything else I should check on them before I crank them (once the woofers are fixed?
dtotheatothevtothee
dtotheatothevtothee OP
18 posts
 
One more question...

Do I need to save that dust cap to reinstall it or is the dome replacement one I got sufficient?
timlub
1,649 posts
 
The dust cap is the center of the woofer. If you have cut your old one off, the voice coil should be uncovered ready to shim. As far as a replacement dust cap? If the caps are made of a harder material, you will most likely have a bit more extention in the mids. If it is a softer material, you will most likely have a earlier roll off in the mids... I say most likely, it depends on crossover points and slopes.
You said that you had a friend that has done this. Have you gotten him involved?
dtotheatothevtothee OP
18 posts
 
There was a domed cover over top of the other black circle you see in the picture above. Are they both dust caps or is the flat black circle something I need to remove?
I don't see a gap to slide the shims in as the black goop seems to make a seal all the way around

I haven't heard from the guy that was going to help so I'm winging it!
timlub
1,649 posts
 
On the photo that you have provided. The center is a magnet. Around the magnet is a voice coil former. They have slid paper in place between the magnet and former to make an even gap. This is the voice coil gap. Without that gap, your voicecoil will rub when the woofer is working. This must be done. You put the shims to balance this gap, You replace the surround. Then remember to remove the shims before you re glue your dust cap back on. For what ever reason. I get the idea that they had a small dust cap, and another larger dustcap over that. If they did that, then yes, put the second (larger) dust cap back on. It can affect the mid range as well as the bass performance if it has much weight.
arnettpartners
312 posts
 
Some 90's had larger dustcaps. It is apparent from your pic that the driver had a large dustcap over a smaller one. You will have to replace the dustcap(s)--after you have removed both of them so that you can shim the voicecoil--with the larger alternative dustcap in order to cover the ring of glue. If Larry gave you the smaller dustcap in the kit, you will have to have him send you the larger ones.
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