Realistic Optimus 5's. Info wanted, advice solicited.

onwardjames

onwardjames

Hoardimus Maximus
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Before I'm flamed for not using the "search"....I did. For 2 hours.

Just scored some Optimus 5's....old ones with the adjustable pots. They're in fantastic shape cosmetically, but hadn't been played much, and not at all in the last 20 years, methinks.

All drivers work, and hoping someone here can point me in the right direction.

My goals for these (had another pair years ago, gave them to a friend who had nothing) is to fix that crossover issue where the tweeters and mids are sharing the spectrum. Recapping with some 1% tolerance Daytons, and was hoping someone could tell me the values. I know there is a 6.8uf, a 33uf, but the other cap I couldn't see the value.

I also know about the mod to the 5b's and the 8b's....but is this applicable to the original 5's.?? I would like to simply correct that issue with off axis sound and recap, perhaps even upgrade the terminals (does that REALLY make a difference?)

All advice and tips welcome!
 

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I just recapped my 8b's today. It cleaned up the mids and highs a lot. Didn't do anything for the off axis problem. You really need to be in the sweet spot. I didn't do the x-over rebuild for a variety of reasons. I think you have to replace the tweeter in the Optimus 5 with an 8b/5b tweeter to use that x- over design. I don't know of anything short of that to correct the overlap. These are very good sounding speakers even with the original x-overs. That's one of the reasons I did the recap first. I didn't want to lose the character of the speakers. Still may try it someday, who knows. Hope I helped a little, maybe others will chime in. Good luck.
Tim
 
Thanks for the input!

Anyone with the values? I'm guessing the third cap is a 3.3?? Does that seem right? I couldn't get it turned over without cutting the wire to see...
 
I only had 2 caps on mine, a 10 and a 4.7. The earlier ones are different and I don't know what the values are.
 
onwardjames said:
Thanks for the input!

Anyone with the values? I'm guessing the third cap is a 3.3?? Does that seem right? I couldn't get it turned over without cutting the wire to see...
Click to expand...
Anyway you can post an image of both, networks? Sometimes the caps have the values facing different directions making them more or less readable. I wouldn't be too surprised if some did post the 5 schematic in the 8b post. If you are searching AK, best way I've found to do that is google "audiokarma optimus 5" and you will likely get to the relevant post quicker. I'm reasonably certain there is at least one 5 post with what you are looking for.
 
Worst case scenario, I'll cut them out and get the readings, but I'll try your search suggestion.

Never had much luck with the search engine here.

Even with ancient caps, these guys have a nice warm sound. I can hear the smearing of the mids and highs, tho....
 
onwardjames said:
Worst case scenario, I'll cut them out and get the readings, but I'll try your search suggestion.

Never had much luck with the search engine here.

Even with ancient caps, these guys have a nice warm sound. I can hear the smearing of the mids and highs, tho....
Click to expand...
Same with my 5b and 7b speakers, though not so much with the 7b speakers. When I rebuilt the networks in my Mach One speakers the difference was pretty significant. After doing the VL mods on another set of Mach One speakers, even bigger improvement, including better imaging.
 
I love those woofers, so with the bottom end covered, seems like you're on the right track fixing the highs. BTW I only use the google search here, seems to work well that way.

I'll be following this, I've always wanted a set of those.
 
onwardjames said:
Before I'm flamed for not using the "search"....I did. For 2 hours.

Just scored some Optimus 5's....old ones with the adjustable pots. They're in fantastic shape cosmetically, but hadn't been played much, and not at all in the last 20 years, methinks.

All drivers work, and hoping someone here can point me in the right direction.

My goals for these (had another pair years ago, gave them to a friend who had nothing) is to fix that crossover issue where the tweeters and mids are sharing the spectrum. Recapping with some 1% tolerance Daytons, and was hoping someone could tell me the values. I know there is a 6.8uf, a 33uf, but the other cap I couldn't see the value.

I also know about the mod to the 5b's and the 8b's....but is this applicable to the original 5's.?? I would like to simply correct that issue with off axis sound and recap, perhaps even upgrade the terminals (does that REALLY make a difference?)

All advice and tips welcome!
Click to expand...

Nova 8B rebuild & crossover re-design

This should keep you busy!
 
Old thread, but I picked up a pair of Optimus 5’s from the granddaughter of the original owner. I’m pretty sure I’m the first person to open them up. The Elna caps appeared original and were still glued in place.

In case it helps anyone, my capacitor values were 3.3 uf, 6.8 uf and 47 uf. I replaced the 2 lower values with film and put a new Nichicon bipolar electrolytic in place of the 47 uf.

The new caps made a huge difference in the mids and tweeters. I think the bass will eventually wake up, but the treated cloth surrounds are very stiff after sitting for a long time. Not bad for a $20 purchase and $10 in caps. The veneer is very nice and the grills are original sign badges.
 

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lqpete11 said:
Old thread, but I picked up a pair of Optimus 5’s from the granddaughter of the original owner. I’m pretty sure I’m the first person to open them up. The Elna caps appeared original and were still glued in place.

In case it helps anyone, my capacitor values were 3.3 uf, 6.8 uf and 47 uf. I replaced the 2 lower values with film and put a new Nichicon bipolar electrolytic in place of the 47 uf.

The new caps made a huge difference in the mids and tweeters. I think the bass will eventually wake up, but the treated cloth surrounds are very stiff after sitting for a long time. Not bad for a $20 purchase and $10 in caps. The veneer is very nice and the grills are original sign badges.
Click to expand...
This was useful for me. I am picking up a pair and was looking for the cap values to place an order so the speakers don't sit around too long before recapping the crossover, thanks.
 
For the solidified cloth woofer surround sealer,, get some acetone, a small paint brush & some cloth rags to clean the surrounds to regain movement. It's a Real pain i might add..Afterwards you'll need to reseal them but I can't help there. I forgot who was making that diy sealant stuff.
Let me know if you have any faulty drivers. Not sure exactly what I have left though.
 
Vintage AR was an eBay seller that sold Roy's sealant concoction. Not sure if they are around or not. I think it was butyl rubber dissolved in some type of acetone like product.
 
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