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JPTL
10-12-2011, 11:43 AM
I just picked up a pair of L20t3's that are in mint cosmetic condition. However when hooking them up to a reliable source, the tweeter in both speakers doesn't work.
Is there a fuse or reset, or is the tweeter blown?
Thanks,
J.P.

Robh3606
10-12-2011, 12:43 PM
I got a pair off Ebay years back and it sounded like the tweeters were blown. When I opened them up someone had installed 70 volt distribution transformers inside. Once I removed the transformers all was good. So when you can pop out the woofers and take a look inside. There are no fuses or reset buttons in the stock speakers.

Rob:)

speakerdave
10-12-2011, 01:10 PM
It's also distinctly possible the tweeters have been blown by the abundance of high frequency distortion artifacts created when an inadequately powered amplifier has been over-driven by turning the volume control to "eleven." It's a common mishap. The remedy is new tweeters, which fortunately are available from JBL.

Val
10-12-2011, 01:40 PM
or is the tweeter blown?

So, as suggested, remove the woofer for access. If everything looks normal then you will want to disconnect the tweeter from the crossover and put a ohm meter across the tweeter. If there is no resistance, it's blown and will need to be replaced. If you find that you have resistance in the 8 - 16 ohm range the tweeter is fine and your problem is upstream from the tweeter.

JPTL
10-12-2011, 02:02 PM
Thanks for the replies. I pulled the tweeters and attached speaker output to the tweeter leads via alligator clips, and applied moderate volume.
No response.
I attached an ohm meter to the neg & pos terminals of the tweeters, and no resistance/no continuity. I can only imagine that both got an output surge that took out both tweeters.

I bought these because I've always liked the sound of L20's - particularly the highs and mids. The cabinets oiled up beautifly and aside from these being really nice looking speakers in mint cosmetic shape, I'm sure they sounded great before their tweeter mishap.
The guy who sold these to me is willing to help with repair if it's reasonable in relation to what I paid for them, however I don't see that as being an option.
Correct me if I'm wrong, but OEM tweeter replacement seems to be the only way to go here & they aren't cheap. IMO, replacing these 035TIA's with anything else wouldn't do these speakers justice.

hjames
10-12-2011, 02:22 PM
I've had L20Ts and L20T3s - if I recall correctly, 035TI and 035tia are the same tweeter but the connect terminal placement is different.

Someone on CL-DC had a pair for $80 I think last weekend ... gone now.
FWIW, I don't have any spares right now ....




Thanks for the replies. I pulled the tweeters and attached speaker output to the tweeter leads via alligator clips, and applied moderate volume.
No response.
I attached an ohm meter to the neg & pos terminals of the tweeters, and no resistance/no continuity. I can only imagine that both got an output surge that took out both tweeters.

I bought these because I've always liked the sound of L20's - particularly the highs and mids. The cabinets oiled up beautifly and aside from these being really nice looking speakers in mint cosmetic shape, I'm sure they sounded great before their tweeter mishap.
The guy who sold these to me is willing to help with repair if it's reasonable in relation to what I paid for them, however I don't see that as being an option.
Correct me if I'm wrong, but OEM tweeter replacement seems to be the only way to go here & they aren't cheap. IMO, replacing these 035TIA's with anything else wouldn't do these speakers justice.

BMWCCA
10-12-2011, 04:50 PM
Check for physical damage such as broken tinsel leads from the tweeter spade terminals to the diaphragm. The wire can be easily broken with mishandling and I've even seen the terminals themselves become loose in the glue with which they're attached which puts "terminal" strain on the connection between the terminal and the tinsel. They can be repaired if you're careful and have the ability to solder very tiny wire without mucking things up further. Try testing the resistance along the leads closer to the actual diaphragm and not just at the terminal and see what you get.


Ask me how I know! :( But I was able to fix one and learn from my mistake before screwing up the others.

hjames
10-12-2011, 06:16 PM
Yep - heres a thread on the 035ti vs 035tia - from an old pointer of BMWCCA (thaks Phil!)

http://www.audioheritage.org/vbulletin/showthread.php?4272-035ti-vs-035tia&p=59290
The thread even has response curves ...

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=8358&stc=1&d=1118456538

JPTL
11-15-2011, 10:59 AM
After finding a pair of 035Tia's on eBay (http://www.ebay.com/itm/JBL-035TIA-TITANIUM-DOME-TWEETER-PAIR-DIAPHRAGMS-LOOK-GREAT-/390359364529?pt=Speakers_Subwoofers&hash=item5ae33b33b1) and losing the bid (sold for $145 :eek:) I decided to see if I could find a pair of complete L20T3's locally. Cosmetic condition not important.
Lo and behold, I got a pair of mint Walnut T3's for $70. The virtual twins to the pair w/the blown tweeters.
So now I have the first pair of L20T3's with the bad tweeters. Should I part these or hold tight until I find a great deal on a pair of 035Ti/035Tia (doesn't seem likely).
Is there a demand for the L20T3 crossovers, woofers, grills or cabinets like there is for their tweeters?

berf
11-15-2011, 12:35 PM
The 115H-1 woofs don't go bad very often, as they're pretty tough and the surround is not a deteriorating foam. They're plentiful on the used market and don't fetch much. The cabinets and networks really don't have much value either. I'd wait it out until you find the right deal on one or two 035tiA's. 035 non-A's are the sonic equivalent of A's but there's some minor behind-the-speaker baffle modification necessary when installing them in T3's due to the terminals being located at 9 and 3:00. There's no real sonic difference between the two but you're best off with two A's or two non-A's rather than a mixed pair only due to the mental benefit of the positive qi. :blink:

The 6" two-ways are dynamite little love generators. Everyone should own a pair. The only thing better are 4406's with biased networks.

JPTL
11-15-2011, 01:08 PM
The 6" two-ways are dynamite little love generators. Everyone should own a pair. The only thing better are 4406's with biased networks.
Although I haven't experienced the 4406, I agree with you re: the L20's.
In fact it was the L20t that turned me on to the JBL home sound in the first place.
My buddy bought a pair new. I couldn't believe that he'd spent so much $ on a little pair of speakers, particularly because he's kind of a cheapskate.
But then I heard them..
He played some Leo Kottke, John Fahey....acoustically 'bright' stuff and I loved their sound. Then he played some stuff with more bass and I was amazed at how these little speakers filled the room with rich, clear sound.
Some 20 plus years later, these speakers are still kicking. He and his wife listen to them constantly.
Aside from beautiful sounding speakers, they're beautiful aesthetically. The workmanship is furniture-grade. In fact the guy who just sold me these T3's didn't understand why I said that a little oil would make the grain glow. He thought they were simulated vinyl walnut grain cabinets.
berf, you've helped convince me that parting these out for the woofers & xovers and likely tossing the cabinets would be sacrilege ;)

hjames
11-15-2011, 01:44 PM
Congratulations! Think I have one spare L20T3 somewhere after selling 5 of them to a friend for a surround system ... and still have a pair of L20Ts suspended as rear surrounds in my multimedia room!



Although I haven't experienced the 4406, I agree with you re: the L20's.
In fact it was the L20t that turned me on to the JBL home sound in the first place.
My buddy bought a pair new. I couldn't believe that he'd spent so much $ on a little pair of speakers, particularly because he's kind of a cheapskate.
But then I heard them..
He played some Leo Kottke, John Fahey....acoustically 'bright' stuff and I loved their sound. Then he played some stuff with more bass and I was amazed at how these little speakers filled the room with rich, clear sound.
Some 20 plus years later, these speakers are still kicking. He and his wife listen to them constantly.
Aside from beautiful sounding speakers, they're beautiful aesthetically. The workmanship is furniture-grade. In fact the guy who just sold me these T3's didn't understand why I said that a little oil would make the grain glow. He thought they were simulated vinyl walnut grain cabinets.
berf, you've helped convince me that parting these out for the woofers & xovers and likely tossing the cabinets would be sacrilege ;)