Realistic Optimus 9

[colehager]

Staggeringly little first-hand information about these online, though I've read the handful of AK threads I was able to find. Anyone encountered these in the wild and/or have an opinion to share?

Going to be picking up a set this weekend––and given how rare(?) they seem, I couldn't resist. I've always had a thing for Realistic, for whatever reason. (My Nova 8Bs might just be my favorite thing I've ever bought.)

Sorry for the open-ended question, just was surprised at the dearth of testimony! If not, I'll circle back to record my impressions (for whatever those are worth).

 

[homebrew]

If any old speaker will do, then the Optimus 9's should fill the bill.

 

[stereofanboy]

If any old speaker will do, then the Optimus 9's should fill the bill.

Gee, I missed where he said that.

Sorry I can't give any firsthand impressions colehager. I always wanted to try a set of those, but never got the chance.

 

[colehager]

Thanks, sfb! I always felt the same, which is why I couldn't help but jump at these. It's just such an interesting design, and it's intriguing to me that Realistic seemed to push these so hard (at least for a year or two there) as their top of the line model––over the Optimus 5b/Nova 8b, which I always understood to be a KLH Model Five "clone" of sorts. The lack of any enthusiastic ranting online leads me to believe it was less of a home run and more of a stepping stone to the Mach One, but who knows. It'll satisfy my curiosity, if nothing else!

 

[maxhifi]

@colehager - I've never seen them in person, or else I'd surely have an impression. I'd buy them out of curiosity too if they turned up for the right price. Curious what you think, make sure to share photos! Also if they're made in the same factory as the 7B, etc. I expect you shouldn't fully judge them before replacing the electrolytic capacitors. Luckily, RS speakers were built to a cost, so there shouldn't be many to replace!

 

[colehager]

@maxhifi – thank you! Agreed about not judging until they've had a little basic tlc. I am not an expert here, but I'll do my best to muddle through. (I am currently happy as can be with my 8bs post "videolady" mod.

One bummer: It looks like the owner had the dome tweeters replaced. Can anyone more experienced than me confirm my suspicion that this appears to have been done very poorly? I'm amazed they left a gap––doesn't that defeat the whole purpose of an acoustic suspension design?

I'll see if I can source the original tweeters and go from there. Happy for any and all advice (not that I expect many will have had direct experience with this model).

 

[maxhifi]

@maxhifi – thank you! Agreed about not judging until they've had a little basic tlc. I am not an expert here, but I'll do my best to muddle through. (I am currently happy as can be with my 8bs post "videolady" mod.

One bummer: It looks like the owner had the dome tweeters replaced. Can anyone more experienced than me confirm my suspicion that this appears to have been done very poorly? I'm amazed they left a gap––doesn't that defeat the whole purpose of an acoustic suspension design?

I'll see if I can source the original tweeters and go from there. Happy for any and all advice (not that I expect many will have had direct experience with this model).


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The domes are obviously not a great substitute. The originals though look like clones of early 70s Philips domes. You might have better luck finding philips parts than original, I bet they'd be a drop in fit. (Obviously need to confirm)

 

[colehager]

Oh, good to know re: Philips. Believe it or not, there actually seem to be a few Optimus 9 tweeters on ebay!

New picture below adds no value, but confusingly––they sound great? Both tweeters were totally dead when I first wired them up (sounded WEIRD), and they only kick in if the High-End dial on the back is positioned just so, otherwise they're silent (and faintly staticky when dial turning).

I was expecting the gap around the replacement tweeters to fully compromise the bass, but that isn't the case at all. The low end is full, rich, not lacking in the slightest (and not boomy either). I know these are an odd design overall, so maybe there is a sub-enclosure? (I need to go reread the older AK thread on these speakers.)

The weak point is clearly the replacement tweeters, as there is a bit of scratchiness (faint distortion) in the highs. Even still, I'm pleased (and surprised) how good they sound otherwise. Very lifelike, a bit less "laidback" than my Novas.

 

[maxhifi]

By all means buy the ebay ones... it's always nice when a project comes together. They look great!

 

[elvi]

RS sold the classic Phillips dome tweeter as a replacement, back in the day.
I still have one somewhere.
2nd on getting a pair from that auction site..

Can't comment on how they stack up, But did listen to a pair in the store..

 

[NH-MAN]

maybe had the same tweeter as the 10 oopps I was wrong

 

[Lavane]

You could probably get away with choosing a nice soft dome found at P.E. for not too much. Those super tweeters that were used don't even seal the cabinet. You don't want any air leaks in that design.
Also I would caushion you on buying larger RS speakers on line. The glue they used to attach the cabinet panels didn't age well. You might wind up with a pair of flat pack speaker kits when they arrive. AK'r @Bodyblue had a pair of Optimus 5B's shipped to him from an ebay seller. And they were packed very well. I saw the pictures. When he opened the boxes most of the panels had separated. I tried to put them back together, but the magnets had shifted as well, locking the voice coils up. I was able to get one cabinet back together properly, but there weren't even enough drivers that were good to use for the one.

 

[colehager]

Thanks, Lavane. Appreciate the warning! Although I've been tempted over the years, I've limited myself to speakers I could physically pick up in the tristate area. I see what you mean, though. These Optimus 9s definitely feel "solid," but if nothing else I fear the decaying veneer would not have survived a UPS truck. (Little chips seem to fleck off every time I touch them.)

I ended up pulling the trigger on some OEM Optimus 9 domes on the auction site, but good to know about the P.E. option! We'll see how it goes. I do have some caps in the mail as well. This will be my first real recap project, and I'm sure I'll screw plenty of things up, but I'm grateful to you, @Bodyblue, @Stuart Pedaso, and Adam S. in the older AK thread for all the discussion and forensic work. (I was sad to read of Adam's passing after enjoying his adventure with these speakers.)

btw, @Bodyblue, sorry to hear about your 5b woes! I wanted those for ages, ended up finding the 8b locally, and I couldn't be happier. (Lucky me, the seller had already applied the VL mod.)

 

[Lavane]

Thanks, Lavane. Appreciate the warning! Although I've been tempted over the years, I've limited myself to speakers I could physically pick up in the tristate area. I see what you mean, though. These Optimus 9s definitely feel "solid," but if nothing else I fear the decaying veneer would not have survived a UPS truck. (Little chips seem to fleck off every time I touch them.)

I ended up pulling the trigger on some OEM Optimus 9 domes on the auction site, but good to know about the P.E. option! We'll see how it goes. I do have some caps in the mail as well. This will be my first real recap project, and I'm sure I'll screw plenty of things up, but I'm grateful to you, @Bodyblue, @Stuart Pedaso, and Adam S. in the older AK thread for all the discussion and forensic work. (I was sad to read of Adam's passing after enjoying his adventure with these speakers.)

btw, @Bodyblue, sorry to hear about your 5b woes! I wanted those for ages, ended up finding the 8b locally, and I couldn't be happier. (Lucky me, the seller had already applied the VL mod.)

How do the 8B's sound with the VL mod? I'm always on the lookout for 5B's or 8B's myself. I have more soeakers than I need, but thats one pair I want to play with. I made new grills for a pair of Nova 7B's. I just don't care for nature grills. I used P.E. grill kits and some repop Realistic badges. I also added a coil to the woofer to force the woofer to roll off where it should. It cleaned up the upper bass and lower midrange.

 

[maxhifi]

How do the 8B's sound with the VL mod? I'm always on the lookout for 5B's or 8B's myself. I have more soeakers than I need, but thats one pair I want to play with. I made new grills for a pair of Nova 7B's. I just don't care for nature grills. I used P.E. grill kits and some repop Realistic badges. I also added a coil to the woofer to force the woofer to roll off where it should. It cleaned up the upper bass and lower midrange.

Those are sharp looking grills. I wonder if some BBC style felt around the tweeters might help diffraction a bit.

 

[nerdorama]

Both tweeters were totally dead when I first wired them up (sounded WEIRD), and they only kick in if the High-End dial on the back is positioned just so, otherwise they're silent (and faintly staticky when dial turning).

Doesn't appear that anyone has commented on the situation with the tweeter controls. It sounds as though they are either dirty, corroded or failed. Try turning them somewhat rapidly from end to end and see if that restores any function. Otherwise you may need to get some potentiometer cleaner, i.e. Faderlube, or replace them. Don't use any contact cleaner as it may ruin them depending on what sort of track is in them. If they are wirewound then go ahead with contact cleaner.

 

[Lavane]

Doesn't appear that anyone has commented on the situation with the tweeter controls. It sounds as though they are either dirty, corroded or failed. Try turning them somewhat rapidly from end to end and see if that restores any function. Otherwise you may need to get some potentiometer cleaner, i.e. Faderlube, or replace them. Don't use any contact cleaner as it may ruin them depending on what sort of track is in them. If they are wirewound then go ahead with contact cleaner.

I learned the hard way not to use contact cleaner on the pots RS used. They weren't the best quality to start with. I use Faderlube a lot now.

 

[Lavane]

Those are sharp looking grills. I wonder if some BBC style felt around the tweeters might help diffraction a bit.

I keep meaning to do just that. I'm gathering parts for another tube amp build and I'm going to add felt to the list. Thanks for reminding me.
I agree some felt may help with the two midrange/tweeters being vertically aligned like that. The Optimus 1B's and Nova 7B's have a very narrow focused sweet spot when listening to them. I'm hoping the felt will help with that some. Move your head side to side, or up and down just a little and its off balance, or you loose some detail.

 

[maxhifi]

I keep meaning to do just that. I'm gathering parts for another tube amp build and I'm going to add felt to the list. Thanks for reminding me.
I agree some felt may help with the two midrange/tweeters being vertically aligned like that. The Optimus 1B's and Nova 7B's have a very narrow focused sweet spot when listening to them. I'm hoping the felt will help with that some. Move your head side to side, or up and down just a little and its off balance, or you loose some detail.

I had a pair of 7Bs for years, but eventually sold them, due to the dreaded "too many speakers" issue. I really liked them, they're certainly one of my favorite all round RS speakers. I think it's incredible the grills are intact on the OPs Optimus 9s, that sort of foam grill usually rots and disintegrates.

 

[Bodyblue]

I keep meaning to do just that. I'm gathering parts for another tube amp build and I'm going to add felt to the list. Thanks for reminding me.
I agree some felt may help with the two midrange/tweeters being vertically aligned like that. The Optimus 1B's and Nova 7B's have a very narrow focused sweet spot when listening to them. I'm hoping the felt will help with that some. Move your head side to side, or up and down just a little and its off balance, or you loose some detail.

That is why those funky Optimus 21s I have (and loaned you) with the twin tweets on top that you set for left or right, smoke the 7Bs for soundstage. There is a set of 7Bs for dirt cheap near me and I am temped but the Optimus' just sound better.