C50 and 4320

[Zilch]

Is there another reference number for those c-50 speakers with the dual 15 inch speakers, such as my c-50 2-way's I believe are comparable to a 4320.C50 was a cabinet designation, the "Olympus." It could be purchased with different components loaded, primarily the S7 (two-way) and S8 (three-way) systems. With an "R" designation (S7R, S8R,) the LE15A woofer used in both systems was supplemented with a PR15 passive radiator to tune the cabinet, so you're not seeing dual woofers, rather a woofer and a passive radiator there.

S8R is considered the more desireable, because, in addition to having the 075 ring radiator "bulllet" tweeter, it upgraded the 1" LE85 midrange compression driver to the more powerful 2" 375, much coveted by vintage collectors.

Indeed, the 4320 traces back to the C50SM, the smaller "Studio Monitor" cabinet (more like C51 "Apollo" in size,) which came loaded with either S7 or S8 ("R" would not fit) systems. It's more akin to the L200B than C50, in my view, though, having different woofer and crossover than the earlier C50SM....

[Zilch]

From a distance I did'nt notice a tweeter, but at the moment I can't act interestedhttp://audioheritage.org/vbulletin/images/smilies/wink.gif

Now my pro dealer says diaphrams are no longer available for the Le 85 driver and said a replacement part would not sound as soft as the original. Also What to do about reconing the LE15A.

Any suggestions? Thank you very much for your help in clearing this up.

BillReplacement diaphragm for LE85 is available, but pricey: D16R2421

The more reasonable titanium alternative D16R2425 is indeed brighter, but not a bad thing.

A suitable reconing kit is available for LE15A, but if it's still playing, new surrounds may more economically resurrect it.

Then, consider "spicing" up your C50's by adding UHF drivers, an easy upgrade....

[Don McRitchie]

I'm guessing that the C50 that Bill owns is actually the C50SM, or more specifically, the D50SMS7 (http://www.lansingheritage.org/html/jbl/specs/pro-speakers/1967-d50sm7.htm). If so, this would be very similar to the 4320. The only real difference is the network. Up until the 4320 was introduced, JBL was primarily a driver manufacturer that also made enclosures into which you could install any number of standard drivers and networks. The 4320 is arguably the first true system design from JBL. This was the fist large JBL to have a custom designed network that was intended to optimize the drivers for the specific C50SM enclosure.

[Zilch]

Ooooo! Never saw that page before. :)

Do we know what crossover and woofer were used in 4320?

[Somebody told me that already, probably....]

C50SMS7 would have LX5 crossover?

[scottndsky]

I'm guessing that the C50 that Bill owns is actually the C50SM, or more specifically, the D50SMS7 (http://www.lansingheritage.org/html/jbl/specs/pro-speakers/1967-d50sm7.htm). If so, this would be very similar to the 4320.

Don,

I think you're right. I'm Bill's nephew and I just joined to post this picture I have of one of his speakers. Maybe you'd be kind enough to confirm the model? They are in very good condition. The woofers were re-coned some time ago because the foam around the outer edge had rotten away. Hopefully that wouldn't take away from their value.

http://img.photobucket.com/albums/v14/scottndsky/Miscellaneous/JBL_C50.jpg

[Chas]

Looks like a 4320 to me. It should be a 2215 woofer, but I don't think they had foam surrounds, maybe someone could confirm - anyway the rest of the line up was 2420/2307/2308. The xover was a 3110.

[andywin]

I have something similar that has no identifiable number apart from the generic cabinet. It uses a 2215, 075, LX5, N7000 and I'm not sure which mid driver as I've never removed it.
Which version is it?

[transducergeek]

I will guess that is a 4333, or, a 4320 with the 075 perhaps added after purchase. (making it a 4333, to my recollection) You have the original Lans-A-loy surround it seems. And the mid driver is likely an LE85 with HL91 horn. (or 2420, number model equivalent)

I had one in my studio in the 70's. And I added the 075 myself. (actually, I added an 077) I could be off though, just guessing.. with some education.. RE

PS, Nice Tannoy's, wanna sell 'em?

[transducergeek]

Ooooo! Never saw that page before. :)

Do we know what crossover and woofer were used in 4320?

[Somebody told me that already, probably....]

C50SMS7 would have LX5 crossover?

The original woofer should be LE15A.

[andywin]

I will guess that is a 4333, or, a 4320 with the 075 perhaps added after purchase. (making it a 4333, to my recollection) You have the original Lans-A-loy surround it seems. And the mid driver is likely an LE85 with HL91 horn. (or 2420, number model equivalent)

I had one in my studio in the 70's. And I added the 075 myself. (actually, I added an 077) I could be off though, just guessing.. with some education.. RE

PS, Nice Tannoy's, wanna sell 'em?

The addition of an 075 and N7000 crossover is almost certainly not a later addition as the cabinet has not been repainted and the crossover cutout is a factory job. It's not a 4333 as the drivers and crossovers are wrong for that model. Could it be the professional version of an Olympus S8 ???

The drivers in the foreground are not Tannoys but are "Dr Bohm". The same speaker was also sold as a Lorenz LP312. They are the rarer version with alnico magnets.

Strangely enough I will be selling some tannoys, not the 12" versions but the far better 111lz;s. They have a lower frequency range and a far superior midrange quality compared to the 12" versions. The 15" versions on the other hand go deeper but again don't have quite the midrange quality.

[Zilch]

The addition of an 075 and N7000 crossover is almost certainly not a later addition as the cabinet has not been repainted and the crossover cutout is a factory job. It's not a 4333 as the drivers and crossovers are wrong for that model. Could it be the professional version of an Olympus S8 ???See pic in post by scottndsky, above. Those cabs came with blocked cutouts for adding the tweeter and crossover, as S8 was an option. The midrange driver will tell the tale. LE85=S7, 375=S8.

4333 would have the long H92 horn as well, no?

You can peek behind the lens to see what driver/horn combination is in there. S8 had a stubby H93 horn on the 375....

[Mr. Widget]

Don,

I think you're right. I'm Bill's cousin and I just joined to post this picture I have of one of his speakers. Maybe you'd be kind enough to confirm the model? They are in very good condition. The woofers were re-coned some time ago because the foam around the outer edge had rotten away. Hopefully that wouldn't take away from their value.

If that is a recone in the original 2215/LE15A frame it is way wrong. The woofer may have been substituted with a 2205A which is also wrong but at least the right cone in the right frame.

In any case to get the correct performance from that system you need to check the nameplate on the woofer. If it is a 2215 or LE15A it should be reconed. If the woofer is a 2205 or anything else it should be replaced with a 2215 or LE15A with a foam surround cone and proper underhung voicecoil.

C50SM or 4320? I believe the only way to tell is to look at the rear of the enclosure. If it is a C50SM there will be a small plaque with that written on it. I am not sure what type of label the 4320s had other than on the grill. There may have been a label on the crossover.

Widget

[scottndsky]

If that is a recone in the original 2215/LE15A frame it is way wrong.

Wrong because they do not appear to be foam surrounds in the picture? I *believe* the frames are the original LE15As, but I would have to defer to Bill on that one.

Is there a preferred or acceptable source for LE15A replacement cones? These were re-coned somewhere in LA by a dealer who was *supposed* to know what he was doing.

Unfortunately, it's the only picture I have so I'll have to defer to Bill for any information on the plaques as well.

[Don McRitchie]

I don't think there is anything wrong with the cone. I blew up the image below and it looks like a standard LE15A/2215B cone with a half roll surround. As to what the system is, it could be either a 4320 or a C50SMS7. The easiest way to tell is to check the crossover at the back. If it is labelled LX-5, it is a C50SMS7. If it is labelled 3110, it is a 4320. The date of manufacture has to be 1967 or later since that is when the JBL logo used on your cousin's system was developed. The 4320 was introduced the following year.

[Mr. Widget]

I think you are right about that surround. At first glance it appeared to be the dark cloth rolled surround as on the 2205, but looking at the magnification it does indeed look like a foam surround. They are usually much lighter in color but that could be an issue with the photo.

If a reputable repair facility claimed to do a proper recone, I would expect that they did.

Widget

[Bill H.]

So, to not let this thread get too long, My speakers do have LE-15A speakers with an Le85 driver, but the network is marked LX-13 and frequency dividing 1323. 8 ohms.
Just as I get interested in old local finds, the wife is making me go on two week vacation at noon today:banghead: I wonder if I could get a quick respnse, so as to leave with a little less anxiety.

Thank you all very much!
Bill

[Mr. Widget]

The LX13 is the Consumer designation for the 3110. This would tend to put it in the 4320 camp... but I am guessing it is a 4320 that was made before the Pro Series was created and therefore before the 43XX designation system had evolved.


Widget

[Don McRitchie]

First off, your system is definitely a 4320. George Augspurger invented the pro numbering scheme in 1968 at the same time as the 4320 was introduced. It likely took JBL some time to change all of the labeling on their components after adopting the new numbering system. It is very likely that they had not yet gotten around to using the new numbers on your components. Therefore, I would suggest that you have one of the earlier 4320's made.

[Chas]

The woofer clamps may have been added later? My 4325's and pictures I have seen of the 4320 have the woofers mounted with screws. Wonder when the clamps were introduced?

[Mr. Widget]

I removed a Blue LE15A from a C50SM and it had woofer clamps. The blue version would put it at '61-'62.

Widget