L65A crossover Help Needed.

[fotodan]

Purchased a pair of L65A's last month, and noticed on one of them the 077 was not working, and L-pad for Brilliance is sticking and making rubbing noise when turning. I purchased a can of Control/Contact cleaner and Lubricant figuring I would remove L-pad controls and lube real good and problem solved. WRONG!!!!!! When removing sub, I noticed on crossover, not sure what its called, a round white cermanic looking tube was burnt and in 2 peices. It was so hot it made a burn mark on the insulation touching it. What is that part and where can it be purchased??

Next problem was after removing L-pads, the one controling the 077 had burn marks on the back of it, removed the cover, and found the insides fried to a crisp, the inner wound spring is burnt into and was hanging out. I cut off part hanging out and tried to insert the remaining back where it belongs, but in need of new one. Have checked e-bay for another crossover but only found one for a Jubal, not the same looking at the pics.
Where can parts be purchased, or even purchase another crossover.
Any help anyone??
Thanks,
Dan

[Zilch]

L-Pads at parts express.

We need pics of the crossover to figure out what's smoked and needs replacing....

[fotodan]

Okay Zilch, I hope these pics help. Are they caps? If they are can they be updated on both speakers??

[hjames]

Okay Zilch, I hope these pics help. Are they caps? If they are can they be updated on both speakers??

Wow, looks like Sprague caps ... but you let the magic smoke out!
What kind of power are you running those speakers with?

[fotodan]

Heather, I purchased these last month, they had MTX subs in them, got a good deal on em, purchased 128H's for them, installed subs, noticed didnt have sound from one 077, removed 128H to clean L-pad for o77, it was fried, noticed burn mark on insulation at crossover and this is what I found. I am running a Kenwood 9100 amp for power.

[hjames]

Well - its possible the previous owner smoked them -
but off the top of my head I don't know what kind of power a Kenwood 9100 amp produces ...
077s don't need a lot of power, but if there are MTX woofers in the box it sounds like a 'bastardized" pair of speakers.
It could be the MTX drivers are not as efficient as the original JBL woofers and when you run them hard enough to get the MTX woofers as loud as you want, you've fed more power to the crossovers that they were designed to take ...

Thats just a guess ...

Heather, I purchased these last month, they had MTX subs in them, got a good deal on em, purchased 128H's for them, installed subs, noticed didnt have sound from one 077, removed 128H to clean L-pad for o77, it was fried, noticed burn mark on insulation at crossover and this is what I found. I am running a Kenwood 9100 amp for power.

[fotodan]

The 9100 is a 100 wpc amp, and is there a replacement I can get now that I have correct speakers back in the boxes?? Or are there any newer ones I can purchase to bring the L65A's back to life??? I am new to the crossover game, but quick learner..

[hjames]

If the Kenwood amp is clean thats shouldn't be too much power if you don't run it wide open into heavily distorted terrain.

My guess is its probably best to rebuild the crossovers to original spec and see how that works - at the least replace the cap and Lpad ... You now have the right woofers in the box - so we'd need to know what exact model you have - apparently there were a few variations ...

From a couple year old message (quoting Giskard on 5/04/04) http://audioheritage.org/vbulletin/s...5&postcount=19

"Well, JBL did a total of five versions of this system that I know of, L65, L65A, L65B, S21, S21-1. When the Jubal first came out we though it was the best thing since sliced bread. Fortunately we got over it. It is still considered a viable system by many and if they're happy that's all that counts."

Also note in the Archives here, this message has a link to at least 3 of the various crossovers mentioned above -
http://www.audioheritage.org/vbullet...98&postcount=3


Here are links to the original JBL crossover schematics:

L65 Jubal - http://manuals.harman.com/JBL/HOM/Te...Jubal%20ts.pdf

L65A Jubal - http://manuals.harman.com/JBL/HOM/Te...Jubal%20ts.pdf

L65B - http://manuals.harman.com/JBL/HOM/Te.../L65B%20ts.pdf


In the L65, the L65A and the L65B schematic, the HF leg in all three uses the same 8 Ohm Lpad,
and has only a single cap (the same one) and in all its c2 ... 1.5 µF

The L65s are nice looking speakers - I considered a pair before I got into this never-ending quasi-4343 project.

[fotodan]

For the last week I have been wondering whether to fix the L65A's or do kinda what you did, and get L200's, and 3106 crossovers, and use the 077's from the 65's. Just not sure which would sound better. Whats really stopping me are the serial #'s on the 65's.... 73280 & 73281..

[johnaec]

For the last week I have been wondering whether to fix the L65A's...

I'd repair them - fixing the crossovers should be easy. While you're at it, I'd also put in bypass caps, (cheap and easy - do a search), and end up with an excellent set of L65A's!

John

[hjames]

No matter what your long term plans are, I'd get the L65As sorted out and working properly. You owe it to yourself to enjoy them for a bit ... while you are doing that you can watch the L65 prices and see what they bring intact and in collectable condition.

I started with 4320s - kinda rough Pro monitor boxes, not particularly collectable, but with a good pair of 15" woofers and 2420 drivers & horns. I could tell they lacked high frequency, so I bought the 2405s (like the 077s) off eBay a year ago (they didn't come with the speakers), and built my own crossovers from a $250 pile of parts. And a lot of tinkering ...

One consideration for me is that I have done enough point-to-point and circuit-board level soldiering that building a crossover from the excellent designs Giskard's posted here wasn't a big leap for me. I built my first heathkit radio in the late 60s ... so I've been doing that kind of thing for quite a while.

For the last week I have been wondering whether to fix the L65A's or do kinda what you did, and get L200's, and 3106 crossovers, and use the 077's from the 65's. Just not sure which would sound better. Whats really stopping me are the serial #'s on the 65's.... 73280 & 73281..

[Zilch]

It doesn't seem the value on that capacitor is readable, so open up the other speaker and see if you can read the value off the same capacitor in the "good" one.

From the looks of things, it's C2, 1.5 uF, the main filter capacitor for the 077, and it was cooked by overheating of R1, 15 Ohms, next to it, which could happen if the L-Pad failed and the user kept cranking on the power. The resistor seems to be O.K., actually, but you'll know more once you get into it.

Verify the values of both components.

Also verify that the 077 in that speaker is still good by swapping it into the other speaker as a test....

[fotodan]

Okay, going to rebuild the n65A crossovers and get years of enjoyment from my 65a's. Is there a certain brand name cap to search for?? My understanding is the cap I am needing to replace is the C2...1.5uF.... Not sure about the by-pass caps... Zilch and Heather might be getting alot of questions from me..... Thanks all for the help.

[fotodan]

It doesn't seem the value on that capacitor is readable, so open up the other speaker and see if you can read the value off the same capacitor in the "good" one.

From the looks of things, it's C2, 1.5 uF, the main filter capacitor for the 077, and it was cooked by overheating of R1, 15 Ohms, next to it, which could happen if the L-Pad failed and the user kept cranking on the power. The resistor seems to be O.K., actually, but you'll know more once you get into it.

Verify the values of both components.

Also verify that the 077 in that speaker is still good by swapping it into the other speaker as a test....

Thanks Zilch... Should I check to see if the R1 is okay?? and if so, would I check for resistance?? I have switched 077 between speakers and 077 is working fine .

[macaroonie]