Page 2 of 3 FirstFirst 123 LastLast
Results 16 to 30 of 35

Thread: 250ti Top End

  1. #16
    Senior Member
    Join Date
    Aug 2013
    Location
    Tours, France
    Posts
    125

    Lightbulb

    Look at JBL's kit.https://www.midwestspeakerrepair.com...le_16_15_1.jpg
    I've cut mine around the same specs (found other pics at that time) and it pushed quite hard on the dome. Scary but sound was just great. And is still! Just to barely touch is not enough, you want a tad amount of pressure.
    http://www.audioheritage.org/vbullet...l=1#post358810
    Good luck!

  2. #17
    Member
    Join Date
    Feb 2010
    Location
    NC
    Posts
    52
    Quote Originally Posted by Malefoda View Post
    Look at JBL's kit.https://www.midwestspeakerrepair.com...le_16_15_1.jpg
    I've cut mine around the same specs (found other pics at that time) and it pushed quite hard on the dome. Scary but sound was just great. And is still! Just to barely touch is not enough, you want a tad amount of pressure.
    http://www.audioheritage.org/vbullet...l=1#post358810
    Good luck!

    Thank you Malefoda.

    Your story gives me more confidence.

    Looking at the domes today I was surprised that there is no spider kind of suspension for the domes. As compared with lower frequency drivers.

    Still waiting for the foam replacements in the mail - I think they've got lost.

  3. #18
    Senior Member
    Join Date
    Feb 2018
    Location
    Annapolis, MD
    Posts
    173

    L250 HF (044-1) Driver vs 250Ti

    Sorry to temporarily hijack this thread, but a quick question. Did the L250 HF driver (044-1) have the foam or was it just on the titanium stuff as used on the 250Ti?

  4. #19
    Member
    Join Date
    Feb 2010
    Location
    NC
    Posts
    52
    Quote Originally Posted by sweet212 View Post
    Thank you Malefoda.

    Your story gives me more confidence.

    Looking at the domes today I was surprised that there is no spider kind of suspension for the domes. As compared with lower frequency drivers.

    Still waiting for the foam replacements in the mail - I think they've got lost.
    Having bought these speakers a year ago and noticed someone has worked on them. I checked the polarity of the tweeter with the wiring diagram. Sure enough, whoever worked on them connected the black strip wire to the + terminal of the tweeter. According to the 250ti BQ schematic the black stripe connects to the - terminal. I assume I can check the other drivers polarity with a battery at the speakers main input terminal.

  5. #20
    Senior Member rdgrimes's Avatar
    Join Date
    Aug 2008
    Location
    New Mexico, USA
    Posts
    2,172
    Quote Originally Posted by sweet212 View Post
    Having bought these speakers a year ago and noticed someone has worked on them. I checked the polarity of the tweeter with the wiring diagram. Sure enough, whoever worked on them connected the black strip wire to the + terminal of the tweeter. According to the 250ti BQ schematic the black stripe connects to the - terminal. I assume I can check the other drivers polarity with a battery at the speakers main input terminal.
    On the JBLs, the black stripe always goes to the "-" (black) terminal on the driver.

  6. #21
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,338
    Sguttag... 044 series had foam also.

  7. #22
    Senior Member
    Join Date
    Feb 2018
    Location
    Annapolis, MD
    Posts
    173
    Quote Originally Posted by grumpy View Post
    Sguttag... 044 series had foam also.
    Thanks for the information...though it sucks. I haven't fired them up in a long time (been a couple of years) but they will go on line in 2019. Since I've reconed the woofers once already and they look like they aren't too far away from needing a refoam job, I'd have to think that the tweeters then would be due for a new set of foams.

    Any additional complications on this model versus the others?

  8. #23
    Member
    Join Date
    Feb 2010
    Location
    NC
    Posts
    52
    Quote Originally Posted by rdgrimes View Post
    On the JBLs, the black stripe always goes to the "-" (black) terminal on the driver.

    Thank you RD.

  9. #24
    Member
    Join Date
    Feb 2010
    Location
    NC
    Posts
    52
    Quote Originally Posted by sguttag View Post
    Thanks for the information...though it sucks. I haven't fired them up in a long time (been a couple of years) but they will go on line in 2019. Since I've reconed the woofers once already and they look like they aren't too far away from needing a refoam job, I'd have to think that the tweeters then would be due for a new set of foams.

    Any additional complications on this model versus the others?
    I'm still waiting for the foam to come in the post but it should be easy enough to put back together. Would be worth your while to refoam your 044's. I'll let you know how different or not my 250ti's sound.

  10. #25
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,338
    Would be worth your while to refoam your 044's.
    Agreed. Last set I had open, the foam had turned to a little pile of goo.

    Even if not so completely degraded, the old foam will likely have lost resilience after 30+ years
    with little support or damping provided. Patience in disassembly is your friend.

  11. #26
    Member
    Join Date
    Feb 2010
    Location
    NC
    Posts
    52
    Quote Originally Posted by rdgrimes View Post
    On the JBLs, the black stripe always goes to the "-" (black) terminal on the driver.
    Someone has messed around with the terminals. The black stripe lead with female spade terminal connects to the positive (+) speaker connection. This means the tweeter is in anti-phase - unless the connection to the xovers is not also swapped around.

    Name:  Tweeter 007.jpg
Views: 183
Size:  94.1 KBName:  Tweeter 004.jpg
Views: 184
Size:  79.9 KB

  12. #27
    Senior Member rdgrimes's Avatar
    Join Date
    Aug 2008
    Location
    New Mexico, USA
    Posts
    2,172
    Quote Originally Posted by sweet212 View Post
    Someone has messed around with the terminals. The black stripe lead with female spade terminal connects to the positive (+) speaker connection. This means the tweeter is in anti-phase - unless the connection to the xovers is not also swapped around.
    If you're trying to suss out the crossover wiring, the tech sheet links found here should help. Shows polarity, pin numbers and color codes.

  13. #28
    Member
    Join Date
    Feb 2010
    Location
    NC
    Posts
    52
    I resurrected this thread to let you know the results.

    I have been very busy but my 250ti's are finally back together.

    Re-foaming the 035's was easy. The tweeters are now less prominent - they sound better. Excellent result.

    However someone who owned these speakers before rewired them and the color coding does not match. Its almost impossible to trace the polarity through the crossovers because speaker resistance for either polarities is almost identical.

    The only way to ensure that the speakers are correctly connected IMHO is with a sound level analyzer.

    Your comments and ideas are most welcome.

  14. #29
    Administrator Robh3606's Avatar
    Join Date
    Apr 2003
    Location
    Rocinante
    Posts
    7,984
    You should verify with measurement. But be careful with the polarity as in the tech sheets. If you look closely at the TBQ it is actual driver acoustic polarity. Looking at the sheet it looks like your tweeter might be correct. You would want a negative on the positive to get a negative acoustic driver output. It would be nice if we knew if the 035 is plus on plus.

    Rob
    "I could be arguing in my spare time"

  15. #30
    Senior Member
    Join Date
    Sep 2005
    Location
    Wash DC suburbs
    Posts
    1,206
    I worked with some 250s have 4 all TI now , new xovers in one set that are Charge Coupled that was not the original Xover for that model. I remember finding the diagrams very confusing and possibly incorrect. Make sure you have the correct diagram too. There 3 or 4 version of 250 speakers, 3 TIs i think including European version and 1 set that was Charge Coupled from the factory. Part of the confusion comes from JBL switching to the current standard or polarity during the time the 250 series was built. Original woofers went inward when touched to a battery to test, positive terminal to the positive battery . It switched at some year but i would think your version is past the switch. I was never (and still am ) sure if I have polarity each driver 100% correct.

    you have gold tweeter , never let it go!! rare
    Think center channel for 250TIs; (2) 108s, a 104 and a 44ti, now what?

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. The JBL 250, 250TI, & 250TI Jubilee Club
    By Storm in forum Lansing Product General Information
    Replies: 44
    Last Post: 02-15-2017, 06:01 PM
  2. 250ti
    By pathfindermwd in forum Lansing Product General Information
    Replies: 6
    Last Post: 06-14-2010, 12:51 AM
  3. JBL C-34 or 250ti
    By sushii in forum Lansing Product General Information
    Replies: 6
    Last Post: 05-29-2004, 04:47 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •