AR 8in woofers 200037-0 and 200001-1

[lARrybody]

Last summer I found a pair of AR18 speakers in a antique shop on the county seat square while on jury duty. I had a pair of AR 15 speakers I was working on and they had radioshack replacement speakers. I borrowed the 20001-1 woofers from the AR18 speakers, but still wanted to finish the 18's someday. Looking around, finding a pair of these 20001-1 woofers on the auction site is not easy. I finally picked up a pair of 200037-0 woofers freshly refoamed and from some 18S speakers along with both inter seal gaskets, outer rings and even screws. I wanted to convert them to look like the AR18 woofers, but decided they were way too nice to alter.  Then I run across two (not a matching pair) of 18S speakers in a small town on my way back from Chicago.  Both woofers were correct 200037-0 and ohmed out at 5 and 5.2 ohms. I finally had my candidates.

I have refoamed probably 30 woofers and the hardest part has always been cleaning the old glue off the woofer cone edges without damaging the cone material. I read this post from DougG in the Advent section and It made a lot of sense. I tried his method with the heat gun and was quite surprised with the outcome.

http://www.classicspeakerpages.net/IP.Board/index.php?/topic/9707-easiest-refoam-method-yet-for-both-masonite-and-all-metal-woofers/

Here are the woofers ready to receive new Boston type "filled Fillet" surrounds. Notice the tick marks I use to center the new surround to the cone.

 

 

Notice how one of the poly (more like rubbery vinyl) dust caps was installed off center. I cut new flat dust caps from the top of a organic egg carton.

Here they are with 64 mm fabric mesh dust caps added and foam gaskets added around the perimeter. I need more practice using my circle cutter for they are less than perfect.

Here they are next to a original 200001-1 woofer. Not a bad visual match.

Here are the differences I can see by inspection. The original AR18 woofer has a 70mm dust cap, but 64mm was the closest I can find.The 20001-1 has eight holes and the 200037-0 has four holes. I have never seen more than four holes used. Both magnets appear identical and are 3 5 /8 in square. The 200037-0 weighs in at 3lbs.10.7 oz.and the 200001-1 is 1 oz. heavier at 3 lbs. 11.8 oz. The 200037-0 has a stamp in a circle of SFT 8 and the 200001-2 SFT 7 with a date code of ROL-7717. I don't know if the voice coils are much different. The 200001-1 ohmed out at 5.3, about the same. My next step is to reform the 200001-1 woofers with the same surrounds and rebuild two sets of AR 18's with the same capacitors and resistors utilizing the identical tweeters. Maybe I will hear a difference, when they are A-B tested together together. 

Will report back what I perceive.

[ra.ra]

Hi Larry, here's just a few observations that come from looking at the drawings for these two drivers. They appear very similar and while they do have minor differentiations, it is unclear how this affects performance specs. The 001 woofer drawing (date 1976) suggests its use in the AR-15, AR-17, AR-18, AR-25 and AR-94. The 037 woofer drawing (date 1980) mentions use in models AR-18s and AR-28s.

All of the major components are fully identical: the sub assembly (basket and magnet); the cone and skiver; and the spider and coil. Other components do show different part numbers, like the dust caps (two caps on the 001; one on the 037) and adhesives. Also, I just noticed that the 001 woof has something called a "weight" (item 11, made of lead) which is epoxied to the cone under the flat dust cap.

Both AR drawings do show eight holes along the outer basket perimeter. The only 8" woofers I am familiar with that actually use all eight holes are early EPI woofers with rubber surrounds - - those use eight wood screws and no T-nuts.