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Radio shack Optimus 7 1973 floor speakers
- Thread starter Kybronco
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- optimus 7 1973
It is more common than you might think. I’m taking apart a JBL Lancer 99 that has no back panel access.
Smiley
Smiley
RTally
Speaker addict
Commonly, there are two ways to access the internals of a speaker cabinet, either through the woofer (or other driver) opening or through the speaker terminal panel. It is rare for the back panel to be removable. In order to make the speaker cabinet as rigid as possible, all the panels (sides, top, bottom, front and rear) are at least glued together.
Many of the older vintage speakers had less rigid cabinets with thin panels. The backs were commonly removable. Less old vintage speakers accessed the crossover through the woofer opening. Many newer speakers use a terminal cup that is easily removable from the back of the cabinet. It is common for the crossover to be attached to the back side of the terminal cup.
The backs of my Optimus 7 are nicely finished, better than most speakers I've seen. The only access is through the front of the cabinet. Fortunately, the 12" woofer has a big hole for accessing inside the cabinet.
Looking great, indeed! And I love the avatar!
Gnesen
Super Member
Thanks. Aside from a few very superficial scuffs these are in outstanding shape. My first impression is that these speakers are especially terrific with vocal, acoustic, jazz, folk, etc.
At first I was a little afraid because there was no output from one of the tweeters, but playing with the L-pads on the back brought back the sound. So these will definitely benefit from a cleaning and new caps.
Gnesen
Super Member
I recapped mine over the weekend (per @ukfan4sure! in this thread) and also cleaned the L-pads. This service has made a huge difference. Specifically, the tweeters have much more output and extension -- everything sounds so much clearer than before. It's like a veil has been lifted.
One very important thing to note: the outer edge of the surrounds on the mids of both speakers were starting to detach from the frame. I glued those back down all the way around the outer perimeter by using some leftover white glue from a re-foam project. The cone and surround material (paper?) seemed to be somewhat brittle, so I applied the glue with a sharp toothpick that I slid underneath the outer edge of the surrounds where it attaches to the frame. It was a tedious process but very worth it in the end. If you have a pair of Optimus-7s, I strongly checking the mids for separation of the surrounds from the frame.
Here's a photo of the mid after re-gluing the outer edge of the surrounds.
One very important thing to note: the outer edge of the surrounds on the mids of both speakers were starting to detach from the frame. I glued those back down all the way around the outer perimeter by using some leftover white glue from a re-foam project. The cone and surround material (paper?) seemed to be somewhat brittle, so I applied the glue with a sharp toothpick that I slid underneath the outer edge of the surrounds where it attaches to the frame. It was a tedious process but very worth it in the end. If you have a pair of Optimus-7s, I strongly checking the mids for separation of the surrounds from the frame.
Here's a photo of the mid after re-gluing the outer edge of the surrounds.
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woofercooker
Well-Known Member
Almost all the mids from the four pair of Optimus 7 I had, had that same separating as yours. Very nice job you did. I used super glue on some of mine and it ate some of the black paint on the flange. I leaned my lesson. Lol. And I agree with the tweeter output extension with new caps. I set my tweeter control at high noon or lower for most listening sessions.
Gnesen
Super Member
Four pair?! Wow, that’s a lot considering how rare (and large) they are.
I have recapped a bunch of RS speakers and none them look tidy. The new caps are just too huge to fit neatly on the crossover.
Nova 10s
Optimus 1s
Optimus 27s
Optimus 1s
Gnesen
Super Member
A quick update to say that I’m really enjoying these speakers. They seem to do everything right.
Unsolicited, one of my 13 yo boys asked me how something so old could sound so good. That’s probably because he’s been paying attention and knows that I tend to run newer/modern speakers in my system. For the record, I think the engineering behind newer speakers tends to make them sound better, or at least more accurate, than older ones, but there are no absolutes.
STA-120B?
I'm helping a neighbor deal with his brother's stuff and have the same setup in my garage, looking forward to cleaning it up and hearing 1973.