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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

Showing 3 responses by timlub

timlub
2,039 posts
 
You will have to remove the dust cap. Take acetone or nail polish remover and drop it with an eye dropper on the glue of the dust cap, this will detereorate the glue, then take a razor blade and gently cut away the glue and lift the dust cap. You will then see the voice coil and gaps that are shown in the picture that you provided. Easily put your shims in and your coil is centered. You are now ready to replace your surrounds.
Good Luck, Tim
timlub
2,039 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?
timlub
2,039 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.
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