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Twin Sons of Different Mothers KLH 5/Optimus 5

Wolverine

Wolverine

AK Subscriber
Subscriber
I had seen in a couple of places that the Optimus 5's design was licensed from KLH or at least very closely copied. As noted in another post I recently have become the owner of a pair of KLH 5's and have owned a pair of Optimus 5's for awhile. Both a very good speakers but at this point even though it has only been a few days I have to give a slight edge to the KLH's. They seem to do bass slightly better than the Optimus and they seem very close in the mids and highs.
 

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They really do look similar, I have to admit. The Optimus woofer from that era was actually pretty impressive. I've got an old Optimus 1B parts speaker around here and the magnet on the woofer is huge.
The tweeter section on those is kind of weird, though. They use multiple tweeters wired in series for the 1B. I wonder if the 3 tweeter models just added a tweeter to the same crossover or if they actually have a different x-over point.
 
audiojones said:
They really do look similar, I have to admit. The Optimus woofer from that era was actually pretty impressive. I've got an old Optimus 1B parts speaker around here and the magnet on the woofer is huge.
The tweeter section on those is kind of weird, though. They use multiple tweeters wired in series for the 1B. I wonder if the 3 tweeter models just added a tweeter to the same crossover or if they actually have a different x-over point.
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I am not sure since I have never opened them up. given their very good condition and sound I just thought it best to leave them alone.
 
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Optimus 5

Picked up a pair of these last night for a great price (free). The cabinets are a little rough but the drivers all look in good shape. 3 tweeters and a 12" woofer. Haven't had a chance to hook them up yet and see how they sound. Are these well regarded? Thank you.
Tiga
 
They are very good speakers. There is quite a bit of information and a lot of favorable comments posted about them here on AK, and elsewhere too. The Optimus 5 is a close cousin, perhaps a twin, of the highly regarded Nova 8 speakers that have the lattice grilles. I am sure that they will benefit from having the crossover capacitors replaced due to their age. If you are not already familiar with doing so, it is a very easy and inexpensive thing to do.

They are keepers! Enjoy! :music:
 
Thanks - just learned how to do a recap this past weekend so that will be part of the plan. Wanted to be sure they were worth putting some work into. Impressed with how solid and heavy they are.

Just did a quick search through an old Radio Shack catalog and it says they go down to 20hz. Really????


Ultra-Hog said:
They are very good speakers. There is quite a bit of information and a lot of favorable comments posted about them here on AK, and elsewhere too. The Optimus 5 is a close cousin, perhaps a twin, of the highly regarded Nova 8 speakers that have the lattice grilles. I am sure that they will benefit from having the crossover capacitors replaced due to their age. If you are not already familiar with doing so, it is a very easy and inexpensive thing to do.

They are keepers! Enjoy! :music:
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Still researching and found where someone thought these were designed/built by KLH. Is that true? Seems to have a resemblence to the KLH 5.
 
tiga said:
Still researching and found where someone thought these were designed/built by KLH. Is that true? Seems to have a resemblence to the KLH 5.
Click to expand...

No, KLH had nothing to do with those - they're just kind of laid out like the KLH Model Five. The Optimus 5 and 5b are really great sounding speakers, however, and are definitely worth recapping and cleaning up. *EDIT> The 3 high frequency drivers all look like the same unit, but the two midrange units differ from the tweeter unit. <END EDIT* The 2 next to each other are wired together and are crossed over at a lower point to act as midranges, whereas the 3rd upper driver crosses at a higher frequency to act as the tweeter. Great looking and great sounding speakers, IMO. :yes:
 
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tiga said:
Still researching and found where someone thought these were designed/built by KLH. Is that true? Seems to have a resemblence to the KLH 5.
Click to expand...

As Audio stated they are a good speaker but only resemble the KLH 5 but were not built by KLH.
 
Thanks for the information. I'm looking forward to hooking these up to see how they sound and make sure all the drivers are working. The cabinets are pretty rough however - the rear corners on one are a little damaged. If I can everything in working order / recapped I'll do some repair of the damaged areas and paint them. I'll try to get some pics posted.
 
Just picked up a pair of these today at GW for $10, thought I had a pretty good score! Got them home, one tweeter/mid array isn't working (hopefully some deoxit will clean that up, in the process of moving so might be a little while...) and the woofer on the other isn't working.

Took the woofer off, tested the speaker wire directly to the woof terminal at low volume and nothing. Any ideas on why it doesn't work?

Also, as for the crossover, two inductors, two 10 ohm l-pads, three different caps (Elna caps...50v) and one metal oxide (looks like) resistor. All point to point wiring. Didn't have a lot of time to look at it too closely.

As for the question about the tweeters, two are the same (mid I think) and one is by itself (tweet). Didn`t notice series or parallel.
 
Year's ago, my older brother managed some Radio Shack stores. I sometimes helped him out with late night inventories and we alway's had lot's of music playing at decent level's. The Nova 8's were alway's are choice, and pretty much the best speaker's in the store. We never even considered the Mach One's. My younger brother owned the smaller 10" Nova 7's and weren't to bad either.
 
One of my woofers wasn't working last night until I disconnected one of the midranges and the movement of the wire brought the woofer back. Must be a loose connection in there somewhere.

newguy1 said:
Took the woofer off, tested the speaker wire directly to the woof terminal at low volume and nothing. Any ideas on why it doesn't work?

QUOTE]
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So I played around with these last night - hooked them up and didn't hear much. After some basic troubleshooting I found the tweeters are shot in each speaker. One woofer wasn't working until I started moving around one of the midrange speakers (must be a bad connection somewhere). Once I got the woofers working I was pretty impressed with the bass output. The midranges on one speaker seem a little more recessed than the other. Probably the recap will help.

The mids and tweeters fit inside a rubber housing that is stuffed with some sort of damping material. Although the mids and tweeter look identical from the face although they use a different magnet. All are 4ohm.

What is everyone's thoughts on replacing the tweeter -should I try to find an exact replacement or go with a new dome tweeter?

Anyone have a list of the caps values? I'm getting excited about restoring these - I was pretty impressed from the little I heard from the woofers and mids.
 
I have a pair of Optimus 5 here, and they had blown tweeters as well. I replaced them with 4ohm textile dome tweeters from Madisound. They were the only ones I could find with the 4ohms and a size appropriate for the hole in the baffle.

While that made a big difference, it was recapping these that really helped. The old caps were stopping the high frequencies from getting to the new tweeters.
 
Did you use the rubber housing that surrounded the original tweeter? I think it only provides a 2.5" opening. Hard to find a tweeter that fits in there - I know as I'm trying to find one to fit that opening for another project I have going on.

Does Madisound still carry the tweeter you used?


*Edit - just re-read your post and I missed where you said you used the baffle. (need more caffeine).

Sleep said:
I have a pair of Optimus 5 here, and they had blown tweeters as well. I replaced them with 4ohm textile dome tweeters from Madisound. They were the only ones I could find with the 4ohms and a size appropriate for the hole in the baffle.

While that made a big difference, it was recapping these that really helped. The old caps were stopping the high frequencies from getting to the new tweeters.
Click to expand...
 
I have a pair of KLH model 5's I finally got the correct woofers for and they have a really nice clean sound but I'm sure the caps need replaced so that will be my next project.

I also picked up a pair of RS 8B's a while back so I guess I should replace the caps on the 8B's too and give them a shot. They sound ok but the KLH's sound much better IMO. Maybe after caps the RS's will surprise me. :scratch2:
 
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