AR48s : 200041-0 mid's rebirth

[Giorgio AR]

Some time ago I renewed the foam (woofer and mid) of my pair of AR48S, no problem for the refoaming of the woofers, instead in removing the old yellow foam of the mid's I have mistakenly removed and ruined the thicknesses present between the foam and the basket!
I remedied by using gasket paper for engine casings of corresponding thickness, thus restoring the correct height of the cones after refoaming, under the photographic equipment of the work.

Mid with original deteriorated foam

Old ring near new rebuilt

New ring, glued and painted in black

AR48S pair mid's

New correct foam (provided by Larry Vintage AR)

New dustcap installed

Mid's reinstalled in AR48S cabinets

[lARrybody]

When I re-foamed the midranges on my AR48S speakers I was unaware or I did not pay attention to the paper spacer ring. I glued the new surround to the metal frame. Now I probably don't have the proper cone height.  Just when you think you might have some expertise in restoring these speakers authentically you run across new information. I don't know how adversely I have compromised the performance. 

  

 

I remember reading a post about re-foaming 4 in midranges in some AR12's by GD70. Fortunately my 12's came to me with midranges already done. I left the dust caps in place using a tone generator app on my iPhone to center the voice coils. If I ever revisit my AR48S's I may correct the foams. I wonder if you can paint them cream like the originals.

[Giorgio AR]

As always, the experience arises with the attempts and mistakes that are made over time, in my case after removing the paper rings and therefore ruined, I asked Larry (AR-v) when I ordered the new surrounds about these thicknesses and he said which were needed to get the mid's back to original specs.
I too am fascinated by the original yellow color of these mid's surrounds, but now after 40 years we have to settle for these foams which are the most similar in characteristics to the original ones.
P.S. As already written in another thread in my opinion these are the best cone mids ever listened to.

[AR55]

I am in the process of renovating a pair of 38Bxi's and wasn't able to remove the existing foam surround and glue without damaging the paper gasket.  Let's face it.  It's a 1/64" thick piece of cardboard.   I'm just not sure what purpose it served.   I can't see how 1/64" makes that much difference.

I may try to cut new gaskets, but if I can't, I'll just glue the new surrounds to the frame and not worry about it.  

 

 

[Giorgio AR]

I don't think the AR38BX mid has this thickness (the AR datasheet from what I read is from 1981, corrected for AR48S).
The 200041-0 AR48S mid shares the magnet with the later 200053-0, but the gasket flange is round and larger in diameter.
I have the mid / high section of the AR48B, slightly earlier than your AR38BXI with mid 200053-0 and during the refoaming, removing the old material, no traces of thickness, note however greater thickness of glue! Same situation in the refoaming of later TNG 2100460, no thickness.

AR48S mid

AR48B mid

AR TNG Mid or Mid/W

This belongs to late AR1MS, early use AR components, in this case the cone is identical to the 200041-0 mid!!

[AR55]

I don't know about the 48B's 4" MR, but the 38Bxi's 4" MR was made by Tonegen & it definitely has a cardboard/fiberboard gasket.  It may not be exactly the same as the gasket on 48S, but it is there.  That is torn cardboard not glue in the second photo.  I had already removed the remains of the glue from the old surround.

[Giorgio AR]

Perfectly visible!

Your attempt to reconstruct the paper gasket deserves: thick paper and the right stiffness, compass and scalpel blade, good dexterity.

I add (I searched my photo archive) a 200041-0 mid, not mine with the intact original paper ring before receiving the new foam.