Picked up an 8-foot refoaming project!

CoogarXR

CoogarXR

Super Member
I always wanted a set of Optimus 900 speakers. I found a guy on CL who had some Optimus gear to unload. I called him up, and turns out he had an Optimus System 600 (semi-integrated rack system, mid-grade optimus stuff, but he had the original box, rack, and all paperwork). He also had two Optimus 600 speakers, and 4 Optimus 900 speakers! Needless to say, I took it all :banana:

Of course all 6 woofers need refoamed, but that's not a huge deal. These are in great shape otherwise. Not even one dented dustcap, grille rip, or anything! He was the original owner and an employee of Radio Shack way back when these were new. Nice guy, and he gave me a great deal. Can't wait to hear 'em!

Here's some pics of the white-cone wonderland (pre-refoam):


optimus-stack1.JPG

optimus-stack2.JPG
 
Register to hide this ad
Welp, I got one of the 900's done so far. The glue is drying right now. I can't decide if I should go for another one before bedtime, heh...

These 12" woofers are heftier than I expected. Heavy magnets, large vented voice coil, thick cone, good stuff...
 
Got two of the Optimus 900s done so far. I tell ya, these aren't the easiest to refoam. The foam kit is too big, so you have to trim about 1/4 inch off the outside edge. Also, when getting the old surround off, it's hard not to smear black goo from the old foam on the white cone. I think the first two turned out OK. I haven't heard them yet, but here's how they look:

optimus-stack3.JPG
 
Nice find and nice job!
I gather you didnt remove the caps and use shims so what is your method?

I've done some using shims but the last ones I did I used a battery to lift the cone, applied the glue and disconnected the battery. Then ran a test tone of about 40hz into it while I fully seated them on the glue. I kept the tone going for about an hour. It worked well and didnt have to worry about dust cap replacement.
 
The centering on these is pretty easy. The foam is mounted on the bottom of the cone, and it fits perfectly snug the whole way around. I glue that first, then let it harden. Then I use tacky glue to glue the other side to the basket. it's a slow-drying glue; I just manually excercize the cone up and down a few times to let the foam settle into the proper position. This is also how the SimplySpeakers kit says to do it.

You probably can't see in the picture, but there is a tiny cardboard ring that lays on top of the foam. it fits exactly to the outer edge of the roll. I glue that to the top side of the foam, and clamp the whole thing to the basket (excercizing the cone every few clamps to make sure it's still in proper position).

These have a pretty strong spider, I don't think they are a lot of trouble to position. I did a set of Mach Ones this way, and they were also very easy to center.

Woofer #3 is drying right now. I wish I had more clamps so I could do more than one at a time...
 
I usually find something the right size and fairly heavy to sit on top while it's drying.
 
Here are some random pics of the refoaming process. These are woofer #3 and #4. #3 is drying, and #4 just got cleaned. As you can see, I am one clamp short, hehe. These square frame woofers take large clamps on the 4 corners, and I only have 3 (I just rotate them every so often while it's drying). I also included a basket shot, since there aren't many pics of the Optimus 900 innards on the web :thmbsp:

refoam1.JPG

refoam2.JPG

refoam3.JPG

refoam4.JPG
 
Well, I got the four 12" woofers done. On to the 8". I have one snag already- the original glue is harder on the 8" woofers. It's more difficult to get off. And, the new foam roll's diameter is slightly too small for me to mount the surround in the original position (underneith). I am going to have to put it on top. According to the SimplySpeakers directions, this is ok. I don't like doing things different than the original, but it just won't fit the other way, unless I trimmed the cone (and I really don't feel comfortable doing that!).
 
CoogarXR said:
Well, I got the four 12" woofers done. On to the 8". I have one snag already- the original glue is harder on the 8" woofers. It's more difficult to get off. And, the new foam roll's diameter is slightly too small for me to mount the surround in the original position (underneith). I am going to have to put it on top. According to the SimplySpeakers directions, this is ok. I don't like doing things different than the original, but it just won't fit the other way, unless I trimmed the cone (and I really don't feel comfortable doing that!).
Click to expand...

If it was me, I'd send those back and call on those here that can help find the right foams. Rick Cobb comes to mind, he's found me some pretty oddball foams before.

All the big shops say it's OK to swap positions front to back or back to front, but it does not mean they are right. The voicecoil will be offset if you put the foam on the front, and it just looks wrong...
 
4343 said:
If it was me, I'd send those back and call on those here that can help find the right foams. Rick Cobb comes to mind, he's found me some pretty oddball foams before.

All the big shops say it's OK to swap positions front to back or back to front, but it does not mean they are right. The voicecoil will be offset if you put the foam on the front, and it just looks wrong...
Click to expand...

Thanks for the input, but it's too late, heh. I already did the front-mount job.

It's funny, These woofers are nearly identical to the fisher DS-810 woofer (I have a set here). The basket and magnet probably came down the same assembly line. I have a pair here and they both say Made in Japan, and are made of the exact same materials except the dust cap and surround (the fisher had a cloth surround and dustcap). The flange is identical dimensionally. If this surround job doesn't work out, I can drop in this set of fishers. I bet they have nearly identical specs too.

Here's the difference in the rear-mounted old surround verses the new front-mounted surround. it's definitely different, but I don't think it looks too bad...
refoam5.JPG
 
Last edited:
I dont really think it matters much. It may look a little neater on the back of the cone but for functionality should be the same. Looks like a wider roll on the new one too and that could change the characteristics but in this case, the speakers arent that exotic.
 
Thanks for your compliments guys. They are all finished today. I tested them and they all sound great. The 600s actually impressed me. Nice full sound. The 900s sound great too, but I just had lower expectations of the 600s, heh.

Here's a couple pics. A close up of the finished 8" woofers, and a pic of the whole stack complete:


refoam6.JPG


optimus-stack4.JPG
 
While I had my refoaming junk out, I went ahead and did a pair of 6x9 car speakers I had too. These were Radio Shack's Top-O-The-Line speakers in 1983. Here's a shot from the 1983 Radio Shack Catalog Page 65:

optimus69-6.JPG


Here's a few of the seller's pics from when I bought them. They are new old stock, but the foam rotted away right in the box:

optimus69-3.JPG

optimus69-4.JPG

optimus69-5.JPG


Unfortunately, nobody makes an orange 6x9 foam :thumbsdn:. I couldn't find one anywhere, so I had to use the standard gray. It does seem to take some of the 80s-bling magic away from it. Oh well, they sound great, and are ready to drop into my 80s-mobile :banana:

optimus69-1.JPG

optimus69-2.JPG


I think all of my refoaming work is finally done! And that, kiddies, is how I spent my Memorial Day weekend!
 
CoogarXR said:
While I had my refoaming junk out, I went ahead and did a pair of 6x9 car speakers I had too. These were Radio Shack's Top-O-The-Line speakers in 1983. Here's a shot from the 1983 Radio Shack Catalog Page 65:

optimus69-6.JPG


Here's a few of the seller's pics from when I bought them. They are new old stock, but the foam rotted away right in the box:

optimus69-3.JPG

optimus69-4.JPG

optimus69-5.JPG


Unfortunately, nobody makes an orange 6x9 foam :thumbsdn:. I couldn't find one anywhere, so I had to use the standard gray. It does seem to take some of the 80s-bling magic away from it. Oh well, they sound great, and are ready to drop into my 80s-mobile :banana:

optimus69-1.JPG

optimus69-2.JPG


I think all of my refoaming work is finally done! And that, kiddies, is how I spent my Memorial Day weekend!
Click to expand...

Those 6x9's are cool. I know component-separates are the best way to go nowadays, but a pair of good-quality 6x9's in the back of a vintage car is something special (Back in the '90's, I had a restored '71 Bonneville that had a good pair of 6x9's and a good-quality cassette-deck, and when I'd be driving along in the summertime with 4-5 people in the car and all the windows rolled down and music blaring, there was no describing it. I loved that car. Had a big 455 (or 454.5... I can't remember) and tight springs and had a really-nice ride to it. It was like a wine-red/maroon color.
 
Gang-Twanger said:
Those 6x9's are cool. I know component-separates are the best way to go nowadays, but a pair of good-quality 6x9's in the back of a vintage car is something special (Back in the '90's, I had a restored '71 Bonneville that had a good pair of 6x9's and a good-quality cassette-deck, and when I'd be driving along in the summertime with 4-5 people in the car and all the windows rolled down and music blaring, there was no describing it. I loved that car. Had a big 455 (or 454.5... I can't remember) and tight springs and had a really-nice ride to it. It was like a wine-red/maroon color.
Click to expand...

Yeah, there's just something about that vintage sound in a vintage car. I have some NOS speakers for the front too. The 5.25" 3-ways from '87 are pretty impressive. Huge magnets, large voice coil, and foam that is still good! I am going to put these in the doors (behind the factory grilles).

I also have a set of 1998 3.5" speakers for the dash, I bought them new, and used them briefly in one car, so they are almost NOS, but not quite, heh. I would have opted for some vintage dash speakers from RS, but they didn't really make any good ones back then.

Here's some pics of the other speakers:

optimus69-7.JPG

optimus69-8.JPG

optimus69-9.JPG
 
Wow that takes me back. I forgot about those speakers.

Those were the first HIFI speakers my dad bought for me when I was 14... :banana:

I loved the smell they had when new..


..
 
You must log in or register to reply here.
Back
Top Bottom