Early C50 Olympus, maybe?

[bobdod]

I've taken the plunge and picked up a pretty cheap pair of C50s. These are a bit of a project. The cabinets are pretty nice, but they are missing the horns. From research I've done, my guess is that these would have come with LE-75 or LE-85? The woofers look to be very early. They are marked LE15 (not 15A). One is blue and the other is part blue and part gray. They were refoamed at some point, but need to be redone again. The crossovers are LX5 age are blue as well. There are no tags on the cabinets. Does anyone know what I have here? Really early examples? Basket case? I am not quite sure what the plan for these should be.

 

[Nyjblbob]

The crossovers are LX5 age are blue as well. There are no tags on the cabinets. Does anyone know what I have here? Really early examples? Basket case? I am not quite sure what the plan for these should be.

Nice start, I think the grey n blue one is 16 Ohms? Never saw an Le15 with the blue magnet Motor,
and a grey frame are they close serial #'s?
You have tube amps? Most vintage 16 ohm JBLs sound better with tubes.
Cabinet looks genuine. Depending on your budget, 375's would better match ,
S8 system that includes 075 Tweets.
the Lx5's and Le15's. Finding Blue flame 375's Could be dam near impossible.
For much less $ Le85's making them S7's.
Are you looking to keep them, or move them along. The Mods should then be considered.
Good Luck!

 

[bobdod]

Nice start, I think the grey n blue one is 16 Ohms? Never saw an Le15 with the blue magnet Motor,
and a grey frame are they close serial #'s?
You have tube amps? Most vintage 16 ohm JBLs sound better with tubes.
Cabinet looks genuine. Depending on your budget, 375's would better match ,
S8 system that includes 075 Tweets.
the Lx5's and Le15's. Finding Blue flame 375's Could be dam near impossible.
For much less $ Le85's making them S7's.
Are you looking to keep them, or move them along. The Mods should then be considered.
Good Luck!

I think my initial thought was to go with a more budget minded approach and find LE85/H91/L91 components for S7 configuration. I've always wanted a set of big JBLs, but can't spend that kind of money. I was able to get these for cheaply enough to not be upside down in them after they are done. I figure if I don't love them after they are done, I can pass them along easily. The cabinets are quite nice, and the grills are all there.
I got better photos of the LE15s (they are still installed in the cabs). It looks like I've got some franken-woofers.
The full blue one is marked 8ohm (sn#28200), the blue/gray one is marked 16ohm (sn#1457). Both are connected to blue LX-5 crossovers. Perhaps these were reconed to 16ohm at some point. I'll need to check them with a multimeter to see what's going on. It wouldn't make sense to have an 8ohm LE15 with an LX-5, so hopefully that's what happened.

 

[Nyjblbob]

Sure bobdod makes sense. After you check the impedance of the unmatched le15's,
I would suggest getting only 8 ohm le85's or 2420's as they would effectively
raise the X-over point to around 800hz. that is better suited for the 1" throat drivers.
you might even look for the longer H92 L-300 type horns that do a better job going down to 800hz
A cheaper and smoother diaphragm would be the Radian brand.
I have been using them in my 1" Altec and JBL drivers for over 20 yrs.
As the NLA Aluminum JBL's are mostly all fatigued

 

[bobdod]

Well, the story didn't get better. The 16ohm labeled LE15 ohms out at 8 ohms, which I think is fine, but the 8ohm labeled LE15 measures 30 ohms. Looks like I'll be looking at a recone possibly. I'll be taking both of these to Miller Sound as anything beyond a basic refoam is beyond my skill set.

 

[Nyjblbob]

They will be in good hands!

 

[bobdod]

Keeping this updated as I go along. The LE-15s are now back from Millersound. I've also found a pair of L91 lenses. My goal was to keep these original and find LE85s and H91s, but the cost is prohibitive. I looked for 2420s as well, but again found nothing in my budget. After doing lots of reading and educating myself on the various JBL drivers, I got pretty lucky and found a pair of 2470s with both original phenolic as well as radian diaphragms. My understanding is that the 2470, 2420, and LE-85 are all the same, other than the 2470 being equipped with a phenolic diaphragm. The 2470s with radians are no different than 2420s/LE85s from what I understand. The last piece of this puzzle is the horns. I am still looking for H91s or 2307s at a responsible price point.

 

[toddalin]

My understanding is that the 2470, 2420, and LE-85 are all the same, other than the 2470 being equipped with a phenolic diaphragm. The 2470s with radians are no different than 2420s/LE85s from what I understand.

Not true. The cases are not the same, just as the professional woofers are not the same baskets.

Note how the back raises out:

while the LE85 has a flat back, and is a different color.

 

[Nyjblbob]

There's another difference from the 2470 and le85/2420 has a shorting ring that has less distortion
same thing with the 2" 2482, and 2440, Would you hear the difference? probably not.

 

[bobdod]

Not true. The cases are not the same, just as the professional woofers are not the same baskets.

Note how the back raises out:

while the LE85 has a flat back, and is a different color.

Yeah, they have different back covers and better connectors. The parts that are relavent to their function are the same. I confirmed this by reviewing the technical documentation from JBL and other sources. Since they will be inside the speaker, I don't care at all what they look like. They will sound the same to any human listening.

 

[EarlK]

There's another difference from the 2470 and le85/2420 has a shorting ring that has less distortion
same thing with the 2" 2482, and 2440, Would you hear the difference? probably not.

I have here 2 different full-page JBL product-sheets for the 2470 driver ( circa 1970 + 1977 ) and both state that the 2470 has a silver-plated shorting ring ( impedance controlling ring ).

These 2470's are functionally the equivalent to the 2420 and le85 driver ( though with better terminals than the le85 ).



BTW; I have the same detailed product information sheets for the 2482 and 2440 and neither make mention of any sort of shorting ring in those larger alnico drivers.

 

[bobdod]

There's another difference from the 2470 and le85/2420 has a shorting ring that has less distortion
same thing with the 2" 2482, and 2440, Would you hear the difference? probably not.

I've heard conflicting reports on this and it's based on inconsistent mentions in some marketing documents vs. others. It could certainly be the case, but no one will hear the difference.

I don't think anyone has cut one open to see. From a manufacturing process perspective, it certainly make a lot of sense to have a model number variation based on diaphragm selection. It would be quite confusing to sell a "2420" but with different diaphragms. It's a lot easier to just give them different model numbers when assembled with different diaphragms at the factory. There certainly could be a difference, but most don't think so and as you say, the humans listening won't know what the tag on the back of the driver says. I am thrilled that enough people think there is a difference because that allowed me to get these for ALOT less than the cost of LE85/2420. I'll still keep looking for a good deal on LE-85s, but I'll enjoy these until then.

 

[Nyjblbob]

This is from the Jbl pro catalog 1976

 

[toddalin]

They will sound the same to any human listening.

Kind of pushing it here. The noted differences, such as "kicking" the back out changing the interior volume/shape will have some impact on the sound even if both drivers are +- to the same spec. I would never mix the different types in a stereo pair.

 

[bobdod]

Kind of pushing it here. The noted differences, such as "kicking" the back out changing the interior volume/shape will have some impact on the sound even if both drivers are +- to the same spec. I would never mix the different types in a stereo pair.

I wouldn't mix and match either, nor do I plan to since I have the two 2470s (converted to 2420s with radian diaphragms).

 

[BBB]

I like the look of these vintage cabinets. I too am restoring a pair of Olympus 50 S7 speakers. They will initially have the JBL 030 load in them, D130, 075, N2600 until I can round up some drivers like the original S7 model.

I'll probably swap the 075 with some JBL "baby-cheek" 2404 tweeters for better HF dispersion.

Just not sure if I should port it using the D130's? Don't really want to add any holes unless I make them S8's...haha, just kidding

 

[Nyjblbob]

It all depends on how far you are willing to go with them.
restoration, or Modded to sound the best they can. S7's,S8's, 4430's
What's your power for them? Room size? how much $$$ are you willing to put in them?
JBL has Soooo Many choices.for drivers, horns, woofers X-overs.
Any Mods are for your own enjoyment, as with too many JBL systems,
The components are often worth more than the complete speakers.