Charge coupled 250Tis

[opimax]

I have the 250s how can I get the new xovers? I don't have the ability to build them unless they were a kit style which I have not found in any thread I have read. The tibq had them but is that a direct replacement? I can do that . I watch audiogon and ebay, any other place to watch? Does anybody have a set for sale? does anybody build them ?

Thanks

Mark

[Titanium Dome]

Do you have the L250 or 250Ti?

[opimax]

Sorry for the confusion! 250Ti and 120Ti are my current Ti collection. And my best speakers

Mark

main system:
NEC 61 xm3
Sony STR-DA9000es
Sony NC555es
Velodyne SPL1200r sub
Panamax 5500 AC Regenerator
JBL 250Ti fronts
JBL 120Ti surround rears
JBL L20T3 surrounds
JBL L20T Center
2 adcom gfa 555 not used currently, have bridged 1 each for the 250Tis when I want extreme volume
Looking for:
2nd Velodyne sub
custom center 044, 104h, (2) 115h-1

[MJC]

There are no manufactured CC networks for the 250Ti, as far as I know. The 250s were last manufactured in '91 and Greg Timbers didn't develope the CC networks until '93 for the K2 S5500.
There have been a few of us on this forum that have built a CC network for various models, 250Ti, L212 are the ones that come to mind, at this time.
What is needed is the schematic of the original crossover to be able to determine what is needed for the CC networks, which is basicly, both the doubling of the # of capacitors and their size.
The caps(@ twice the original values) are then wired in series pairs(one pair for each original, single cap), with the commom point of those pairs connected to the + side of a 9V battery.
The result can be amazing, I built the CC for my L212s.

[Zilch]

The caps(@ twice the original values) are then wired in series pairs(one pair for each original, single cap), with the commom point of those pairs connected to the + side of a 9V battery.

... each point individually through a separate 1.5 or 2.2 megohm resistor, the "-" terminal of the battery being connected to "common."

[MJC]

... each point individually through a separate 1.5 or 2.2 megohm resistor, the "-" terminal of the battery being connected to "common."

Ah yes, I forgot to mention the resistors.

[opimax]

what about the european ones?tibq?? or could I pay someone here? eventually? (not pay but get built,lol)

any suggestions? maybe get Khorns instead (never! just threatening in case it works)

Thanks for the replys

Mark

[Titanium Dome]

There are some members here who take on projects like this, but they're busy and often backed up. You might want to figure $1200–up for starters.

The price of parts keeps rising and accounts for most of the cost. I almost had a pair built for me, but the cost jumped a few hundred dollars due to rising parts prices, so we agreed not to do it.

Once your interest is known, if someone here wants to do it, you'll probably get a PM. If you don't...

[MJC]

Just in parts for a 3-way CC network was around $150, or $300 for the pair. Plus the time it took to build them. So for a 4-way it would be even more.

[opimax]

my thought is this
I am 50 now, my hearing is deteriating, these will be the best speakers I probably will ever have, I was told I am part off a new contract at work so I can and should do this now before my hearing and money go away. If I ever do sell these I would recoup at least some of the money for this upgrade if not most. I listen to them for any audio/computer/TV/movie useage (except 10 minutes before sleep)4 hours a day or more so per use it is well worth having the best

The money is high but worth it I hope. I don't think I can do anything to save on costs such as know somebody that sell caps, do part of the work myself like dig holes for the deck I had built once, or even offer a barter of audio equipment that the experts would laugh at, so the price is the price they deserve what they get!

1 question now before I hopefully get PM, I still need to build a center channel which will require some Xover work, although I am sure it would benefit from it too being CC would it "need" or would the timbre of the 250 change that much that the center "must" be CC also? ie modified 120ti xover

thanks

Mark

[MJC]

1 question now before I hopefully get PM, I still need to build a center channel which will require some Xover work, although I am sure it would benefit from it too being CC would it "need" or would the timbre of the 250 change that much that the center "must" be CC also? ie modified 120ti xover

Welcome to the fifty and over club, I'm only 1 1/2 years from 60. My hearing is good enough to still tell the diff.
As for the center, I was planing on building a CC network for my center, but I've put that off. There is some difference between it and the main L/R CC, but being most is voice thru the center, when watching movies, its not that far off. Even when listening to multi-channel music.
With the case of my L212s, the size of the center box and drivers are exactly the same as the mains, so only the xover is different.

[grumpy]

If I ever do sell these I would recoup at least some of the money
for this upgrade if not most.

Not to burst anyone's bubble, but typically one would have to find a
knowledgable, interested party -and- have some sort of traceability
and legitimacy info regarding the design and work performed before
even getting a fraction of what went into customized speakers... especially
if your time or someone else's is considered.
Unmolested speakers (even if poorer performers) often sell for
substantially more.

Frankly, I'd simply ignore all of that and enjoy the crossover improvments
reported in these forums as improving an already very capable loudspeaker
...
and save the old crossovers, just in case (& yes, I walk the walk... as
concerns about my morphing 4430's have been recently noted )

-grumpy

[Robh3606]

There was a CC network for the L250Ti. They did the Jubilee version with an 050 Gold tweeter. Here is the link for the schematics and drawings.

http://www.audioheritage.org/vbullet...=250ti+jubilee

Rob

[opimax]

Grumpy, thanks for the info on value, honestly doesn't come into play as I would hope to keep them w/me until the end, just uneeded rationalization.

Rob, would the different tweeter and I guess the different Xover to begin with work correctly w/the non Jubilee? I remember Giskard built one either from scratch or upgraded a non Jubilee xover. Actually this is above me and would take whatever I can get

I like the group buy idea


Since I will will need complete help on the center later I will worry about that then. My center does mostly music when I am even slightly critical as concert DVDs are my main movies. Still mostly 2 channel so definetly worth while to CC these guys!!

Mark

[Guido]

I changed my 250ti classic edition which is very close to the 250TiBQ to charge coupled networks. It's helluva work. I frequently build cc networks for the monitors of my customers. Normally I build them from scratch. The Problem with the 250ti was that I wantet to keep the PCB and the inductors of the old network and this is a PITA.

I think Giskard built cc networks for member JBLNut. See here:
http://www.audioheritage.org/vbullet...250ti+networks

I doubt you'll get them lower than 1 k$