JBL C50 Olympus Serial Numbers

[henflet]

Can I determine the year of manufacture of Olympus speakers given the speaker serial numbers 46499 and 46500. I am going to sell a set and want to provide proper information. The speakers have a single bass and two lenses above. Thru one lens I can see the bullet tweeter (075 ring radiator?), but I can only see a horn mouth thru the other lens. Is there a way to positively determine it is a 375? Since these cabinets predate the passive radiator, is that a means of determining the year of manufacture? Is there an easy way I can upload a photo of this system for your analysis? Thanks from a Newbie (first post).

[yggdrasil]

Use manage attachments when writing a post for uploading pictures.


The throat of a H93 horn will be 2" wide.

[henflet]

Thanks for the reply rggdrasil! Regarding the 2" throat (driver outlet?) for 375's, I can only view the horn mouth (horn outlet?) by looking up into the lens. The diameter of the mouth is about equal to the height of the lens. Please see photos.

[Zilch]

I see in the site library that Olympus was offered without the passive radiator through 1964.

I see blue paint on the horn, I believe. If the drivers are also blue, that would make them "early."

We cannot tell from the serial numbers because those records have been lost.

You'll either have to remove the lens or the woofer to determine whether the MF drivers are 375's....

[pelly3s]

hmmmmm why the lens over the bullet

[Zilch]

hmmmmm why the lens over the bullet

Owner perceived it as "Beamy," perhaps?

[henflet]

Zilch, thanks, I will remove the lens as you suggest. I assume I can then peer down the horn and measure the throat diameter of the driver. Can't get to the speakers till the weekend - they're stored 80 miles from here..

pelly3s, I have no idea why there is a lens over the bullet - is that unorthodox?

Sorry for all the questions, but this is new to me. Must I remove the woofer to determine if the driver is painted blue? If I did remove the woofer from this sealed(?) enclosure how would I reseal the cabinet when I reinstall the woofer (gasket, caulk etc?) If the driver is painted blue, does that add extra rarity, character, or value to these speakers? Here's a picture of the "Bullet" driver. Does it look as expected (like 075)? TIA

[henflet]

I forgot to ask if anyone can identify the type of wood used on these speakers. I think it is oiled walnut, but hope someone can verify that. TIA

[JohnK]

That cabinet is walnut.
There is a very good chance that it has the 375. It is rare to find a 075 in a system with an LE85. If the horn is stubby and the throat is 2" diameter it's a 375. While looking down in it, don't get confused and take into account the depth of the driver throat. The driver throat is straight sided, while the horn is the tapered section.

BTW, it is a really early one, the lenses appear to have wooden parts. The conditon of the cabinet is remarkable. You have a real gem there!

[henflet]

Thanks JohnK! Yes, the lenses are made of wood - I had no idea that was significant. Do you know when they started using another material?
Does anyone know what was the first year the Olympus was made (I see them in the 1962 Catalog)? Is that the farthest back we can trace them
I have a hunch the previous owner acquired these when they were first produced (he was an audio shop owner and presumably a JBL dealer). Any ideas on the meaning of the first two digits of the serial number? I assume the last three digits are the actual production number - might that be correct? For example with my serial numbers 46499, 46500 Could the first two digits be the year (19)64 reversed, and the speakers were the 499th and 500th ones produced in 1964. Does anyone know if JBL ever used any such conventions? Sorry for the incessant questions but this mystery compels me. TIA

[Zilch]

http://audioheritage.org/vbulletin/s...588&#post85588

[glen]

Does anyone know what was the first year the Olympus was made (I see them in the 1962 Catalog)? Is that the farthest back we can trace them TIA

They were not listed in a 1959 brochure I saw online (see attachment below).
But they might have produced them earlier than 1962 since I have what appears to be an unaltered Olympus cabinet containing a blue "roundback" LE15 (no "A") and an LE75 (S-6 system).
There's a brochure on this site showing the LE15A that is described as "circa 1960", and by 1962 the LE15A seems to have superceded the LE15, so either the C-50 Olympus was produced before 1962 or JBL (or the local dealer) was installing the older drivers in their cabinets.

The 1959 brochure did list the C-49 "Dale" enclosure so the C-50 "Olympus" would most likely be the next enclosure offered after the 1959 crop.
(Note that the C-55 model was a shortened version of the model number C-550 utility horn loaded enclosure introduced in 1955)

[henflet]

Great information!! Thanks, Men!! Well it seems imperative I remove the woofer to determine two things: color of 375 paint, and the woofer model LE15 or 15A. If I discover a LE15 then that means the Olympus' I have were vintage 1960 or 1961 since Olympus not made in 1959, and LE15A commenced in 1962. Do I have that correct? Are there any other things I should look for when I'm inside the cabinet?

When I reinstall the woofer are there any tricks to ensure the cabinet seal (should I have gasket material on hand, for example)?
Does anyone know if the passive radiator installed 1965 and later actually improved performance? Are there scans or other technical info to support this or was this possibly advertising hype? I ask this because I was told that the PR was subsequently dispensed with, and I note that it was not a part of early high-end Klipsch enclosures. TIA

[henflet]

I have found another difference between my Olympus' and another set I viewed recently. Mine has a second connection plate next to the dividing network which HF and LF connectors and a 4-step rheostat(?). This was not on the other set. Is this normal?

[henflet]

Wow! I just thought of something which might allow the dating of my Olympus speakers' serial numbers. I also have the matching C58 Delphi Equipment Cabinet with all the original electronics. Perhaps the serial numbers of one or more of the electronics could reveal dates. The components are Ampex reel to reel, Thorens turntable, JBL Graphic Controller/Pre-Amp, McIntosh Tuner, JBL Amp. For example look at the Thorens - can that be dated? I can post any of the other serial numbers if anyone knows how they can be cross referenced. TIA