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250Ti only
02-10-2005, 12:17 PM
Hi Everyone,

My 250Ti's are from 1986, teak veneer
I have modified/improved them over the years:
1.moved the crossover outboard, flexible mounting at rear1989,
2 rewired with MIT wiring 1989
3 soldered connections with Cardas,1989
4 reinfoced the rear of the cabinet with 1 inch MDF,'92
5 reinforced front and side walls using lead plates, glued and screwed, '94
6 braced internal walls using old table legs especially around the woofer
7 added lead plate to bottom of speaker, remounted tiptoe type feet
8 had a lead weight made for the top of the speaker, '96
9 had JBL authorized repair depot bypass 1 capacitor at their suggestion'98
10 reconed woofers by JBL '98
11 changed damping to cotton felt on walls& hanging strips,removed fiberglas
12 added speaker enacoms---excellent improvement, especially to bass, 2003
13 added 3/8 inch felt to exterior front baffle-lovely improvement 2003
All of these changes made very noticeable improvement to sound--indicating the basic design, drivers and crossover were capable of much better sound than as sold. The main things I have enjoyed is the extra delicacy, imaging and dynamics.

Still love these speakers & expect further improvements with right work.
Comments, suggestions, critique all welcome.
Are there improvements for the drivers?
Are there any parts of the crossover that I can upgrade without messing up the sound? Capacitors, resistors, inductors?
Would I gain an improvement by hard wiring the crossover parts to a board of more ideal material using better wire?
Why do Enacoms, speaker and AC, improve the sound?
How can I battery charge the caps?
Hope this may be of interest or provide ideas for some.
Cheers,
250Ti only

Jakob
02-10-2005, 04:46 PM
Hi!

Very interesting! It would be nice if You could post pictures of Your work. My 250 ti's are still in original condition. I'm looking forward to the day Giskard has finished his work with the biased crossover so I can copy them :D . I guess that will be a nice upgrade.

Regards: Jakob

FredEmmerich
02-10-2005, 08:57 PM
Excuse my ignorance, what is Cardas and what is Enacoms?

Fred

250Ti only
02-11-2005, 09:17 PM
There has already been a biased crossover. We shd work from that design.


Hi!

Very interesting! It would be nice if You could post pictures of Your work. My 250 ti's are still in original condition. I'm looking forward to the day Giskard has finished his work with the biased crossover so I can copy them :D . I guess that will be a nice upgrade.

Regards: Jakob

Jakob
02-14-2005, 12:05 AM
You are free to use any design You want. I guess what You mean is that You should use the network for the 250ti Jubilee? I think that Giskard will do just that (correct me if I'm wrong). And when it comes to picking the right stuff and put all the components together in such a way that it fits in the original 250ti with the bar straps I put my money on Giskard.

Jakob

250Ti only
02-14-2005, 11:34 AM
Cardas eutectic solder.
Kook uo Harmonix website for Enacoms

Pete
Excuse my ignorance, what is Cardas and what is Enacoms?

Fred

John
02-14-2005, 11:55 AM
Just MHO but those cabinets sound like they are TOXIChttp://audioheritage.csdco.com/vbulletin/images/smilies/puke.gif

Lead is not a material I would be adding to my house's contentshttp://audioheritage.csdco.com/vbulletin/images/smilies/nono.gif

250Ti only
02-14-2005, 06:01 PM
Very true. I sealed the lead with paint before install. Do you think there would be any ongoing problem? Thanks, Pete



Just MHO but those cabinets sound like they are TOXIChttp://audioheritage.csdco.com/vbulletin/images/smilies/puke.gif ead is not a material I would be adding to my house's contentshttp://audioheritage.csdco.com/vbulletin/images/smilies/nono.gif