Hello! - please help:
My friend have a pair of the big, old JBL - L300...
and wonder if they can be made "up to date" with
small / careful modifications ???
If you have any experience with these,
please post here!
(and, will it be difficult splitting the filter, for bi-wiring?)
Arne K
NORWAY
My friend have a pair of the big, old JBL - L300...
and wonder if they can be made "up to date" with
small / careful modifications ???
If you have any experience with these,
please post here!
(and, will it be difficult splitting the filter, for bi-wiring?)
Arne K
NORWAY
Hi Arne,
You don’t have to split the filter. This is what I would do. Make a new or get a used xover between the LE-85’s and the 077’s and run the woofer right from the amp. I would run a electronic xover for the woofer to horn transition, but you don’t have to.
Cross the LE-85 to the 077’s at about 8kHz or higher if possible. You can frequently find N7000 xovers on ebay, but the N8000 is kind of rare. It may be easier just to make a new xover with premium parts. If you don’t use the premium parts, at least bi-pass the cap with good audio grade caps.
Cover the baffle around the mid-horn and the 077’s with 7mm foam or felt (remove the lens first so the foam goes right to the edge of the horn). Cut strips of the same foam and wedge them between the fins on the rear of the lens, but not more then 10mm in from the back edge. There should be a round area open to the horn mouth. This will help to control any baffle diffraction as the sound wave travels through the lens. Wrap the mid-horn very tightly with some heavy rubber or neoprene. You can use large wire ties to hold the rubber tight around the horn, the more the better.
In the photo, you can see the foam on the baffle and wedged into the back of the fins. You can also see the N7000 which I totally rebuilt with Solen coils and caps. I may eventually replace the L-Pad with fixed value Caddocks.
Email me if you have any questions.
Rodd Yamashita
You don’t have to split the filter. This is what I would do. Make a new or get a used xover between the LE-85’s and the 077’s and run the woofer right from the amp. I would run a electronic xover for the woofer to horn transition, but you don’t have to.
Cross the LE-85 to the 077’s at about 8kHz or higher if possible. You can frequently find N7000 xovers on ebay, but the N8000 is kind of rare. It may be easier just to make a new xover with premium parts. If you don’t use the premium parts, at least bi-pass the cap with good audio grade caps.
Cover the baffle around the mid-horn and the 077’s with 7mm foam or felt (remove the lens first so the foam goes right to the edge of the horn). Cut strips of the same foam and wedge them between the fins on the rear of the lens, but not more then 10mm in from the back edge. There should be a round area open to the horn mouth. This will help to control any baffle diffraction as the sound wave travels through the lens. Wrap the mid-horn very tightly with some heavy rubber or neoprene. You can use large wire ties to hold the rubber tight around the horn, the more the better.
In the photo, you can see the foam on the baffle and wedged into the back of the fins. You can also see the N7000 which I totally rebuilt with Solen coils and caps. I may eventually replace the L-Pad with fixed value Caddocks.
Email me if you have any questions.
Rodd Yamashita
Attachments
Your friend is a lucky man; the 300's are IMO the greatest effort JBL has ever made in loudspeakers. I once tried to buy the raw drivers and the tweeters (o77 ring radiator) were unobtainable and over $600 ea. I still have one of the original brochures of this speaker.
As well as rubber & duct-tape like Rodd has used, duct-seal works a charm for damping horns and speaker baskets.
dave
dave
I know you can't see it in the photo, but there also are a number of muffler clamps under the duct tapeplanet10 said:
Rodd Yamashita
Arne,
Try this JBL link for information about the crossover;
http://www.jblproservice.com/navigation/Network Schematics.html
This will give you a diagram/schematic of the design if you care to update say the capacitors which would improve resolution. Or bi pass the existing caps.
The equivelant in the JBL Pro monitor was the 4333/4333A/4333B.
The latter two versions were biamp version with a switchable crossover. The drivers are identical to the 300, the crossover is number 3133.
I would image the Aleph (Aleph 3 or 5) amplifier on the horn and Slot if biamped would be magic, I currently use the Aleph 2 on my diy 4345 JBL 4 way wth a passive crossoover, its very smooth.
regards
Ian
Try this JBL link for information about the crossover;
http://www.jblproservice.com/navigation/Network Schematics.html
This will give you a diagram/schematic of the design if you care to update say the capacitors which would improve resolution. Or bi pass the existing caps.
The equivelant in the JBL Pro monitor was the 4333/4333A/4333B.
The latter two versions were biamp version with a switchable crossover. The drivers are identical to the 300, the crossover is number 3133.
I would image the Aleph (Aleph 3 or 5) amplifier on the horn and Slot if biamped would be magic, I currently use the Aleph 2 on my diy 4345 JBL 4 way wth a passive crossoover, its very smooth.
regards
Ian
Lansing Heritage
Arne,
you will find lots of information about JBL speakers and also about the L300 or 4333 Monitor here:
Lansing Heritage
Lansing Heritage Library
Lansing Heritage Forum
L300 Summit
Best regards,
Norbert
Arne,
you will find lots of information about JBL speakers and also about the L300 or 4333 Monitor here:
Lansing Heritage
Lansing Heritage Library
Lansing Heritage Forum
L300 Summit
Best regards,
Norbert
JBL L-300
If you get or have access to audioXpress magazine, in the September 2001 there is article called " Resurrecting a Vintage JBL Classic " featuring the L-300. They do a complete rebuild on it.
I have been wanting to get a pair myself to rebuild. A friend of mine back in 1976 bought a pair and they made a lasting impression on me, very quick and powerfull bass. I could never afford a pair back then. If I remember correctly they cost approx $2500.00 per pair Canadian, a lot of cash back then.
DOUG
If you get or have access to audioXpress magazine, in the September 2001 there is article called " Resurrecting a Vintage JBL Classic " featuring the L-300. They do a complete rebuild on it.
I have been wanting to get a pair myself to rebuild. A friend of mine back in 1976 bought a pair and they made a lasting impression on me, very quick and powerfull bass. I could never afford a pair back then. If I remember correctly they cost approx $2500.00 per pair Canadian, a lot of cash back then.
DOUG
Attachments
I've got the L65, the L300's little brother, with the same tweeter.
About the crossover, I must say that replacing the stock caps with mundorf or audyn caps gives a much better, smoother and more detailed sound than simply bypassing the caps, especially to get the grains of the tweeter and the mids.
Also replace the stock inductor on the horn which is probably iron-coiled with a decend aircoil or if you got the money, a tritec or so.
Greets
About the crossover, I must say that replacing the stock caps with mundorf or audyn caps gives a much better, smoother and more detailed sound than simply bypassing the caps, especially to get the grains of the tweeter and the mids.
Also replace the stock inductor on the horn which is probably iron-coiled with a decend aircoil or if you got the money, a tritec or so.
Greets
L300 Upgrades
Hi,
I authored the article in Audio Xpress about the L300 rebuild.
Some of you may find the phots that I took durign the rebuild useful. If so just email me and I will dispatch a set to you.
George🙂
Hi,
I authored the article in Audio Xpress about the L300 rebuild.
Some of you may find the phots that I took durign the rebuild useful. If so just email me and I will dispatch a set to you.
George🙂
L300 Upgrade
Hey George,
I'd be grateful to see your work and article on the L300 rebuild project; I am rebuilding/tweeking mine,, all good spirits & hints welcome;
Thx in advance...
Philippe
Hey George,
I'd be grateful to see your work and article on the L300 rebuild project; I am rebuilding/tweeking mine,, all good spirits & hints welcome;
Thx in advance...
Philippe
L300 Mods
Hi Philsad,
I have uploaded the files on this email. If you have problems readign the file let me know.
BTW: I have just renovated a pair of L110 speakers. They sounded excellent... getting near the quality of the Yamaha NS1000Ms that I use.
My L300s were imported from France, where they seem to still be very popular. I must say that I would like to have another go at a renovation on L300s. They are very nice to work on.
George
Hi Philsad,
I have uploaded the files on this email. If you have problems readign the file let me know.
BTW: I have just renovated a pair of L110 speakers. They sounded excellent... getting near the quality of the Yamaha NS1000Ms that I use.
My L300s were imported from France, where they seem to still be very popular. I must say that I would like to have another go at a renovation on L300s. They are very nice to work on.
George
L300...follow up
Greetings George, thank you; nope I can not see any file,, or have I no clue to see it... Thanks anyways.. if you have a chance, mabe you can email me directly, philippe.sadoughi@wanadoo.fr; indeed, much fun refurbishing these old babes for another 40 years of duty...!😉 Cheers...
Greetings George, thank you; nope I can not see any file,, or have I no clue to see it... Thanks anyways.. if you have a chance, mabe you can email me directly, philippe.sadoughi@wanadoo.fr; indeed, much fun refurbishing these old babes for another 40 years of duty...!😉 Cheers...
I had a set of L200's that were the first incarnation of the L300's. But someone had modified mine. they had the JBL bullit tweeters mounted in the top like the L300 has the slot/ring.
Unbelieveably efficient. years later i sold them to a friend and he ran them with a 5 watt per channel jambox until he could afford an amplifier and they sounded pretty good to. they just didnt get very loud, but loud enough.
There hasnt been much info on the L200's. im curious about the development of the L200 through to the L300 range.
Zc
Unbelieveably efficient. years later i sold them to a friend and he ran them with a 5 watt per channel jambox until he could afford an amplifier and they sounded pretty good to. they just didnt get very loud, but loud enough.
There hasnt been much info on the L200's. im curious about the development of the L200 through to the L300 range.
Zc
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