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jblnut
06-09-2003, 12:49 PM
Hi All,

I've been gone for a while but I'm glad to see the forum is up and running again! Anyway, on to my questions...

I was lucky enough to find someone willing to sell me a pair of L250's about 6 months ago. I've spent a lot of time now getting to know them and I must say they are quite an impressive pair of speakers. Not perfect though and that brings me to the point...

Last week I stumbled across someone selling all the parts to upgrade an L250 to 250Ti on ebay (kinda surprised that I didn't read about it here first). Everything is included - both 044Ti's, both upper mids and both 250TI crossovers complete with the Monster Cable. It didn't reach the reserve but the seller and I reached an agreeable price, so the parts are on the way.

I'm curious to know if:

1) Has anyone here ever gone through this upgrade before ?

or

2) Has anyone heard the L250 and 250Ti and would be willing to comment on the differences ?

I am hoping this upgrade smooths out the upper mids some, and takes care of the volume linearity problem my L250's seem to have. By that I mean that if I get the sound adjusted perfectly for lower volumes (using either the attenutators in the back or an EQ), it doesn't sound right at higher levels (too much highs, not enough lows).

I'm also excited because the newer crossover allows bi-amping/bi-wiring. I was doing this with my XPL140's and it (despite my skeptical anticipations to the contrary) did make a noticable difference in clarity and soundstage.

Anyway, thanks much for any responses. I'll be happy to post my results here if there is any interest.

Craig (aka jblnut)

4313B
06-09-2003, 01:10 PM
"I was lucky enough to find someone willing to sell me a pair of L250's about 6 months ago."

Lucky you! :)

"1) Has anyone here ever gone through this upgrade before ?"

Yes, a few times.

"2) Has anyone heard the L250 and 250Ti and would be willing to comment on the differences ?"

Yes, I've A/B'd them. The 250Ti not only measures "better", it actually sounds quite a bit better as well. LF seems tighter, midrange a bit cleaner, HF and UHF significantly smoother with greater efficiency and lower power compression. UHF response improves, going from -6 dB at 18 kHz to -6 dB at 27 kHz. BIG difference if you listen to vinyl.

"I'm also excited because the newer crossover allows bi-amping/bi-wiring."

Sounds fishy, no biwire or biamp ability with the N250Ti. Are you sure someone isn't sending you the N250Ti BQ and a pair of 035Ti's instead of the N250Ti's and 044Ti's?

jblnut
06-09-2003, 01:41 PM
Thanks Giskard - wish I'd asked here first....

From looking at the pictures I can clearly see that it's a 035TI
and not the 044Ti tweener. The mid is correct I think (104H-2).
The crossover has me confused though - it clearly says 250TI on it and you can see the dual speaker wire inputs. Was this not the correct crossover for the 250TI ? It not, what was it used on ?

And on a sadder note, how will the 035TI tweeter sound in there?
Perhaps not as much (any) of an upgrade from the 044 that I have now ? I'd hate to do all the work and end up worse off than where I started....


Here is the link to the parts...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3027689636&category=3276&rd=1

4313B
06-09-2003, 02:05 PM
I looked at the picture and no, that isn't an N250Ti network, the N250Ti network is roughly two to three times that size. I wish I had a picture to show you but I don't :(

That's not even the N250Ti BQ network.

Another clue is the wiring, the original Ti series used color coded Monster Cable.

The 035Ti is a very capable HF transducer. I'm not real fond of the plastic construction, but JBL loves it because it is relatively cheap to make, is highly linear from transducer to transducer, and smokes pretty much all previous designs, excluding the 044Ti.

jblnut
06-09-2003, 02:15 PM
Thanks again Giskard !

Now the real mystery - what exactly is that crossover network
and what was it used on ? It looks a lot like the one on my XPL140's, but of course those say "XPL140A" on them. It would certainly appear to be a 4-way crossover and it does say "JBL 250Ti" on it.

Any ideas ? ? ?

If it fits, I think I'm still going to do it. I *love* the high end of my 4410's and now that I just did some research, I realized that's the 035Ti in there. I know the 104H-2 will be an improvement over the paper LE5-11 so the upper mid swap is a no-brainer.

It's just down to the crossover now....

jblnut

4313B
06-09-2003, 02:28 PM
Well, it's some version of the 250Ti network, I just don't know which one right now.

DavidF
06-09-2003, 09:53 PM
There are two clues to indicate that the crossover is the "BQ", bi-wire capability and the switch controlled L-pads on the network. The prior ti networks used metal bars to connect the various combinations of attenuation. Beats me why it is not so indicated.

Craig, I have to say it knowing you will find out eventually. The 104H-2 and the 104H-3 are not equivalent to the 104H used in all the Ti models. They are fine models, nevertheless, but just not the original poly cone model. The 104H drivers are available from Harmon at about $120.00 each with shipping.

DavidF

4313B
06-09-2003, 10:20 PM
David is correct, that network is the BQ version. My error was in thinking the BQ version had three switches. As David also points out, although the 104H-2 and 104H-3 are identical in function, the 104H is not.

Send me a PM if you need 104H's.

jblnut
06-10-2003, 06:47 AM
Wow, I'm really glad I asked about all this now :-)

Now that we're on the subject of the poly mids, what exactly is the difference between the 104H and the 104H-2/3 ? I have the -2's in my 4410's and really like the sound. What will be the problem if I were to use them in my 250's with the new crossover network ? Is it an efficiency or impedence issue ? Is it a frequency response issue ? My LE5-11's are probably the "tiredest" part of my system. The paper is discolored and I'm sure it's been affected by humidity over the years.


I guess what I'm asking is this - will the difference be subtle (ie somthing I could equalize out) or dramatic ?

Thanks again for all the info !!!

jblnut

4313B
06-10-2003, 07:26 AM
The 104H has a filled polypropylene cone. The 104H-2/104H-3 has a felted paper cone. Electrically, they are pretty similar. Acoustically the 104H-2/104H-3 is slightly "flatter" in its response. Both transducers are + or - 3 dB from roughly 200 Hz to 7 kHz. The 104H has slightly lower distortion.

I'd give what you got a try and if you like it you're done. If you don't, then you can get a pair of 104H's.

Robh3606
06-11-2003, 06:18 PM
Hmmm

That crossover is the spitting image of my XPL200A networks. Same switch positions and high freqency contour switch other??

Robh3606
06-11-2003, 06:21 PM
Not sure if this is what you had in mind Rob

4313B
06-11-2003, 07:43 PM
Yes, thanks Rob :)

jblnut
06-12-2003, 01:55 PM
Well the parts arrived today. Here's the story...

035TI - simply will not fit gracefully into a L250 cabinet. It's designed to be screwed in from the front but the 044 in there is anchored from the back. No real easy way to make this one fit - damn.

104H - no big deal, easy replacement.

Crossover - not exactly a great fit, but no too far off either. It will fit into the space where the attenuation "bars" are now with about 1/16 to spare on each side (easy fill with some silicone).

So, my dilemna now is - where to get some 044TI's ? No sense swapping everything out and leaving the old 044's in there. Does anybody have leads/prices on what a pair of 044Ti's would run?

Thanks again for all the help !

jblnut

:(

Rex Mills
06-12-2003, 02:59 PM
jblnut..Standard answer for 044ti is to keep your eyes on ebay for a while. I saw a pair go recently for only $50.00 for the pair. Not often will you find them that reasonable, but occasionally ?
Good Luck:)

4313B
06-15-2003, 10:51 AM
If you need the 044Ti-1 as used in the original 250Ti send me a PM. The 044Ti as used in the 18Ti, 120Ti, and 240Ti will also work if you drill out the mounting bolt holes. The 044Ti-1 is still currently available brand new, the 044Ti is no longer available.

jblnut
06-15-2003, 05:28 PM
I finally got a few hours free on Saturday so I dove in. I swapped in the new crossover and the 104H-2 (the 035Ti wouldn't fit as we discussed earlier). The result ? Welll...

1) The bass was noticeably impoved. Now it might have been because I was unable to completely seal the area around the new crossover (smaller than the original). Long term I could make some wooden pieces to seal perfectly but I don't think I'm going that route because...

2) The 104H-2 *completely* overpowered the other drivers. The deliacte balance that makes the L250 such a joy to listen to (Even for long periods of time) was shattered. Now maybe the correct 104H for the 250TI would cure this, but I'm going to quit while I still have the ability to go back.

I realized that I really love the sound of the stock L250. It's not a "wow* kind of sound like my XPL's that dazzles you. It's more a relaxed competence that you come to enjoy more and more as you get to know the speakers (and your music collection). There are simply no "holes" in the response - nothing is missing and nothing is exaggerated.


Unless someone can make a compelling argument that I should spend another $500 on 044TI's and 104H's, I'm going to consider this experiment done and live a long a happy life with my L250's.

At least until the next pair of 250Ti's or XPL200's show up on ebay :-).

Thanks VERY MUCH to all that reponded (especially Giskard). Your knowledge of these products is invaluable to someone like me.
I love the JBL sound and have many pairs in the house, but I lack the technical knowledge and parts bin experience that many of you have.

jblnut

4313B
06-15-2003, 05:55 PM
"Unless someone can make a compelling argument that I should spend another $500 on 044TI's and 104H's"

Not really without getting the original N250Ti networks as well.

"I'm going to consider this experiment done and live a long and happy life with my L250's."

Can't say I blame you :)

Ezel
06-18-2003, 01:41 PM
Being an owner of a pair of 250TI's I believe your experiment was very helpful at least for me as I am also looking a way to upgrade my 250TI's. Now with your results I guess I should stop my intentions of upgrade...

"At least until the next pair of 250Ti's or XPL200's show up on ebay :-)."

At that point I recommend you to follow up the German E-bay where you can find 250TI's.. (almost every week..)

Good luck

jblnut
06-19-2003, 07:46 AM
Wow - I guess there's always some way to upgrade what you have, but where would you go from the 250ti ? I'm not sure what you could do to improve a 250Ti beyond the already high level of performance it's capable of. Even my humble experiment showed me that different isn't always better - somtimes it's just different.

You'll get a lot of opinions on what would be "better" than a 250TI (electrostatic panels, B&W, JBL 4XXX monitors, etc), but if you're happy with them, I say leave well enough alone.

Have you looked at your electronics ? Is there anything you could do there ?

Thanks for the tip on the German ebay. There does seem to be a regular supply of 250Ti's there for quite reasonable prices. But how would you get them crated and shipped to the States, and what would that cost ???


jblnut

4313B
06-19-2003, 08:08 AM
"Wow - I guess there's always some way to upgrade what you have, but where would you go from the 250ti ? I'm not sure what you could do to improve a 250Ti beyond the already high level of performance it's capable of."

I dunno, maybe charge coupling the networks?

Ezel
06-19-2003, 08:20 AM
Well.. .))

Curiosity was the driving force behind the human advance in the history.. I guess the reason behind to seek an upgrade for my 250TI was my curiosity.

I was checking whether it would be possible to have a new biwirable Network (The network of 250TI Jubilee N250 TIBQ) fitted on an 250TI. After discussing that issue with some people I decided that It will not worth it so I have cancelled that project.

"Have you looked at your electronics ? Is there anything you could do there ? "

I have a pair of Audio Reserach Vt 150 SE monoblock power amps with a Audio Reserach LS2B MKII preamp. All the cables are Van den Hul (SCS-2 for speakers MC Gold and integration for interconnects). The source is a Sony XA7ES. So far it is very good. I am happy with them but this do not prevent me to experiment further for a better sound.. Again.. Curiosity kills the cat!!

"Thanks for the tip on the German ebay. There does seem to be a regular supply of 250Ti's there for quite reasonable prices. But how would you get them crated and shipped to the States, and what would that cost ???"

I have purchased my speakers from Germany. The seller shipped the huge speakers internationally on their own packaging.. They have arrived scratch free. maby I was lucky.. But It really worthed to take the risk..

It looks difficult but Germans are in general very reliable and trustable people. The problem is to convince and persuade them to sell the speaker to you.. Once you have a deal with someone you could be sure that he will deliver it. At least that was my experience. I have purchased many items from German E-bay and never failed. But to be on the safe side I recommend you to discuss every details.. On the other hand I guess this should be a principle to apply on all internet trades.. isn't it?

By the way there is now one pair of 250TI jubilee on auction with very very low price (EUR 700.- ??)

Ezel
06-19-2003, 08:36 AM
Originally posted by Giskard
"Wow - I guess there's always some way to upgrade what you have, but where would you go from the 250ti ? I'm not sure what you could do to improve a 250Ti beyond the already high level of performance it's capable of."

I dunno, maybe charge coupling the networks?

That sounds interesting..

What is the meaning of " charge coupling" and how can we do that?

I really wonder if it will worth such an upgrade? what will be the expected sonic change?

4313B
06-19-2003, 09:36 AM
Hello Ezel

You can search this forum for charge coupling or biasing. Several members have posted links worth pursuing. I asked the designer what he thought about biasing L250's or 250Ti's and he said the difference is staggering. He also said it was a ton of work and a real mess. You might want to just rebuild the networks from scratch. He pointed out that he finally got to "officially" bias a pair for production, the fifth and final version, the 250Ti Jubilee. I have no problem with posting a new charge coupled version of the original 250Ti schematic if there is enough interest.

*****************************************

http://www.audioheritage.org/html/profiles/jbl/l250.htm

Ezel
06-19-2003, 01:08 PM
Originally posted by Giskard
I have no problem with posting a new charge coupled version of the original 250Ti schematic if there is enough interest.



Wow.... Staggering.. Eh??

That sounds interesting. I would love to have a copy of that schematic. In case there won't be any interest please feel free send me a copy with a PM. I think it worths to experiment..

4313B
06-19-2003, 01:17 PM
Hey, he designed them. If he says an original 250Ti with a biased network sounds staggering compared to stock then I believe him.

I'll draw the biased N250Ti schematic up in a few days.

Don C
06-19-2003, 09:48 PM
How about swapping out the midranges for a pair of 093ti? i have been thinking of trying this.
Don C

4313B
06-19-2003, 10:00 PM
One thing I've learned about G.T. after 25 years. He doesn't advocate swapping this and that too often. He is very specific with his networks and drivers. Quite a bit of design is empirical which is why trying to use math and formulas often doesn't work.

"How about swapping out the midranges for a pair of 093ti?"

Standard answer - "Won't work." :)

Feel free to give it a try though :)

DavidF
06-20-2003, 12:17 PM
Following on the idea of changing the upper-mid driver to the 093Ti and Giskard's note related to his interaction with G.T. as a system designer. I agree that the 3-inch dome replacing the cone upper-mid makes practical sense. So much so I was entertaining the idea myself (though not into the L250 system). When does an upgrade become a redesign? I can claim to be no more than an enthusiast armed with a little experience with crossover filter design. Looking back into the history on this website, much of the enthusiasts experience with JBL and Altec in growth years of HiFi involved mixing and matching components with stock crossovers designs. Perhaps due to the similar "family" characteristics of the limited number of drivers, and the level of knowledge involving crossover design, this component matching scheme produced acceptable results when combined in a two- or three-way system. Certainly by the time the L250 was in design stages, the knowledge of filter design had increased significantly. JBL had more and more drivers produced solely for the consumer market and their passive crossover designs were now very much system/model-specific. The L250 filter design is, no doubt, a time-intensive design tuned to the specific drivers used in the system. As Giskard mentions, formulas and theories take you to a point where only listening and trial-an-error will exact the ultimate level of performance.

My point? When we move to swap out drivers in a proven and comprehensive design such as the L250 et al, we are more likely to upset the balance of the design and end up with a downgrade rather than an upgrade unless we are willing to modify the crossover design, as well. At this point we are no longer upgrading the system but are embarking on an actual redesign.

4313B
06-20-2003, 12:41 PM
Thanks for the post David!
Well stated :)

Robh3606
06-20-2003, 12:45 PM
At this point we are no longer upgrading the system but are embarking on an actual redesign.

I agree with you there. I actually tried the 093 swap in a Jubal. And you know it sounded decent measured like hell. Network needed a redesign as you point out. Did a real hack job and used the 1/3 octave EQ to iron it out. Sounded better measured very good. Sounded better and more closely matched my mains. Left it there until I got my 801C coax center built. It is a viable swap but not a simple drop in. There are many driver combinations that JBL never tried because some flat out don't work or they are way to expensive to manufacture and sell mass market or the driver combinations were not available depending on the vintage. As home builders we are making a pair so we have the option to try almost anything reguardless of what the final cost may be. Lets hope we get lucky and find good combinations that do work well together. Now can our home brewed creations compete with the clasics?? That's a tuff one and without the real thing to go against?? I would like to think they can but it's kind of a arogant statement to make and at least for me I steal/copy and borrow as much as I can from the original designs. I guess as long as we are happy that's what matters. We may end up with a real winners and it's too much fun not to try.

Rob:)

4313B
06-20-2003, 12:53 PM
Original N250Ti schematic modified for biasing:

4313B
06-20-2003, 01:02 PM
Well maybe arrogant is a bit strong. :) Let's pick on the L166 for a minute. That system can benefit from putting the transducers in a vertical array, or at least in an L112/120Ti-type array. There are little things that can be done to improve certain aspects. Others have pointed out various restructuring projects. The 4350/4355 for instance; Free the 12-inch 3-way from the dual LF and put them in a vertical array for home theater use. That's SOP for in-wall Home Theater installations and it sounds fantastic.

Robh3606
06-20-2003, 01:52 PM
"Well maybe arrogant is a bit strong."

Yeah I quess it is just couldn't think of another word. You are right there are simple things like your example that can make a big diference. Nice work on that schematic. Just another example of what we as individuals can do.

Rob:)

4313B
06-20-2003, 03:19 PM
Yeah, without manufacturing and marketing constraints we have more options available :)

4313B
10-27-2004, 05:12 AM
Originally posted by Don C
How about swapping out the midranges for a pair of 093ti? i have been thinking of trying this.
Don C 16 months later...

Update with info on "XPL250" (http://audioheritage.org/vbulletin/showthread.php?s=&threadid=2031&highlight=xpl250)

jblnut
03-28-2005, 06:57 PM
OK Folks, it's show time !

I may be wrong, but these pictures would seem to suggest that I was able to commission somone on this board to design and build some charge-coupled, bi-wireable, adjustable 250Ti networks. I say commission because these are the work of an artist both sonically and visually. I just unpacked them and took a few photos as I was installing the first set in the right speaker. I ran out of time and energy before I could get the other one done so that'll be tomorrow night. They will need some time to break in and I'll need some time to get used to them before posting any meaningful impressions. But just from 30 minutes of panning the balance back and forth I can sum it all up in one word..

Smooth....

Stay tuned for more details as this story unfolds....

Guido
03-29-2005, 02:23 AM
I know that style ;)

Looks lightyears better than my mess when it comes to building filters :D

dieterj
03-31-2005, 12:31 PM
How is the Soundifference against the original Crossover?
Nice Solen Caps :)

jblnut
03-31-2005, 02:03 PM
How is the Soundifference against the original Crossover?
Nice Solen Caps :)

Thanks for asking - I had meant to post this last night....

I finished the second speaker last night fairly late. I only had time for a few album sides and I had to keep the volume down (sleeping kids). What I can tell already is that there's a profound sense of balance that wasn't there before. The response is much smoother and vocals especially are much clearer. Remember I'm coming from original L250 xovers here (but I did have 044Ti and 104H already) and not 250ti's. I'm going to get used to the sound (1-2 weeks) then put the batteries in the upper crossovers. From all I've heard and read, this might be an even larger difference than what I just did. After a few weeks of that, I'll remove the "bridge" wires and use two amps in a bi-wire config.

Overall, I am extremely pleased with the results. I listened to side 1 of DSOTM last night - something I've probably heard 100 times. I heard new things that I had never heard before :applaud: .

Whoever made these is to be commended. The guy who helped him on some of the details and - I'm told - might have worked as a loudspeaker designer at a familiar west coast firm is also to be praised. The knowledge and experience these guys have is truly priceless and we're all lucky to have their input.

I've heard some outstanding speakers in my life, and I'm ecstatic to say that mine are quickly closing in on the best of the best. When I'm done with the changes in 3-4 weeks I think I'll finally be "there".


I'll post some better pictures of the crossovers over the weekend...


jblnut

jblnut
04-03-2005, 06:12 PM
Well I tried to wait as long as I could, but I'm only human :)....

Yesterday I hooked up the batteries to get the benefits of the charge-coupled networks. I also removed the bridge wires and hooked up the second big yamaha. I have one amp driving just the LE14's and the other amp drives the top 3 drivers. Both amps are 260 w/c and seem to have "adequate" power ;) .

Please understand that I'm not trying to sound like a magazine reviewer here so I'll steer clear of the tired cliches you read in the audio magazines. What I can tell you is this - every free second I can spare I'm in there listening to them ! It's freakin' addictive now and it just sounds GOOD. The bass is clear and extremely powerful. The midrange is realistic instead of sounding like a speaker. Snare drums sound like snare drums and vocalists seem to hover in the air in front of the speakers. The high end is totally smooth and never harsh even at high volume levels. Someone said that it would be "staggering" and that's a good way to describe it. I'd love to hear a "stock" pair of 250ti's sometime just to hear the difference the charge-coupling makes. I'm sure the bi-wiring and second amp help out too (they did on my XPL's). All of my older nits about the L250 are gone. They sound the same (superb) whether the volume is library quiet or dance club loud. And the balance of the mids between the 104H and 1008H is so much smoother now.

It's funny for me to go back in this thread and see my earlier comments. At the time I was very happy with the stock L250, but I couldn't forget the sound of those other xovers I had for a few days. Even though it wasn't a great matchup with the drivers I had, I knew the potential was there.

Consider me one extremely happy owner of some truly "one of a kind" 250Ti's:applaud: .

Bravo Giskard !!!!!!


Here are some better photos of the upper and lower xover boards....

jblnut

Charlie4350
04-03-2005, 08:59 PM
That is truly a great story with great results, and beautiful work. In my closet are the sacrificial 3107's with the hope that, some day . . . the right person will cross my path. You're a lucky man.

chuck

4313B
04-03-2005, 09:34 PM
I'm very glad you like them jblnut! It's always a bit risky doing custom work like that.

They are indeed one of a kind. From what I understand the only other two pair of original 250Ti's that have been biased reused many of the stock parts - only the caps were changed out to Solens. I guess those boards ended up being huge triple deckers. I'm pleased I was able to make yours a bit more "friendly" - separating out the LP obviously helped. All your components are HUGE compared to the stock stuff - small coils, NPE caps, metallized mylar caps, etc.

B&KMan
04-21-2005, 09:15 AM
They are indeed one of a kind. From what I understand the only other two pair of original 250Ti's that have been biased reused many of the stock parts - only the caps were changed out to Solens. I guess those boards ended up being huge triple deckers. I'm pleased I was able to make yours a bit more "friendly" - separating out the LP obviously helped. All your components are HUGE compared to the stock stuff - small coils, NPE caps, metallized mylar caps, etc.

hi again Giskard, I continue my quest for build a best network as possible for my 4343 and thanks for your pict on tread "4343 crossover modified" ... I go here and find manys informations about biais charge. For more comprehension what is original schematic for compare your wonderful work ???

Thanks Jean

:)

4313B
04-21-2005, 09:37 AM
http://www.audioheritage.org/vbulletin/showpost.php?p=2306

:)

B&KMan
04-21-2005, 11:17 PM
http://www.audioheritage.org/vbulletin/showpost.php?p=2306

:)

Hi Giskard,

I'm not shure...

Your link link with your modified schematic. but the original is not dc charging right ???

So for more comprehension it is possible to send a original schematic with out dc charging for compare what and where the value change in your improve plan with dc charging???


Thanks again.

Jean

:)

4313B
04-22-2005, 02:29 AM
http://audioheritage.org/vbulletin/showthread.php?t=2362