250TI Jubilee spikes

[CLASS A]

Dear all
I have recieved my pair of 250 ti jubilee last week and absolutly over the moon with them. My concern is regarding the stability of the speakers. I have concret floor with carpet and as the speakers only have round metal feets, they rock about when I gently push them. I m sure there must be a better solution to get them sitting firm. Unfortuneatly, there is no way to remove the round feets, I have taken out the cross over to look inside and there are no screws attaching the feets within. Have any of you got a better solution to stabilize the speakers.
I have also noticed with I took the cross over out to realise the capacitors used are of low grade quality ( elna ) blue in color. Has anyone used better quality capacitors and of what make.
Thanks in advance.

[4313B]

The bypass capacitors go a long way in improving the performance of the larger capacitors.

One can also use charge-coupled Solen capacitors to great effect.

The most expensive route is to replace all the stock capacitors with SoniCaps. They don't require charge-coupling or bypass capacitors.

[CLASS A]

Originally posted by Giskard
The bypass capacitors go a long way in improving the performance of the larger capacitors.

One can also use charge-coupled Solen capacitors to great effect.

The most expensive route is to replace all the stock capacitors with SoniCaps. They don't require charge-coupling or bypass capacitors.

Thanks so much for that Giskard. The physical size of capacitors will be the limiting factor of choice. If I change to the solen charged coupled capacitors, do you think I will get a worth while improvement for the cost involved and if I go the whole hog and choose the sonicaps, do you think they will fit within the network and what sort of improvements can I expect?.
Thanks again..

[CLASS A]

Originally posted by Giskard
The bypass capacitors go a long way in improving the performance of the larger capacitors.

One can also use charge-coupled Solen capacitors to great effect.

The most expensive route is to replace all the stock capacitors with SoniCaps. They don't require charge-coupling or bypass capacitors.

The jubilee cross over network has the charged coupled version. There is a 9V battery connected.

[4313B]

Yes, capacitor size can be a real problem if you are sticking with the stock network boards.

The problem with systems like the Jubilee is that it costs considerable cash to start trying various solutions due to the complexity of the networks.

Charge-coupled Solens versus SoniCaps, versus stock... huge cash layout for the sake of a decent A/B.

Does your version have charge coupled bypass capacitors in addition to the main capacitors?

[CLASS A]

Originally posted by Giskard
Yes, capacitor size can be a real problem if you are sticking with the stock network boards.

The problem with systems like the Jubilee is that it costs considerable cash to start trying various solutions due to the complexity of the networks.

Charge-coupled Solens versus SoniCaps, versus stock... huge cash layout for the sake of a decent A/B.

Does your version have charge coupled bypass capacitors in addition to the main capacitors?
I m not sure, whats the differences?. I only saw all of the capacitors being the same size and same color ( blue Elna )
cheers

[4313B]

The bypass capacitors are very small and are usually located next to their larger capacitors. Can you post a picture?

[CLASS A]

Originally posted by Giskard
The bypass capacitors are very small and are usually located next to their larger capacitors. Can you post a picture?

I will take a digital photo soon and e mail it to you.
Thanks.

[CLASS A]

Giskard

here is one of 3 photos of the network. Cheers

[CLASS A]

2nd

[Don C]

Is there a battery?

[CLASS A]

3rd

[CLASS A]

Originally posted by Don C
Is there a battery?

yes, there is a 9v battery.

[CLASS A]

here is my set up....

[4313B]

The bypass caps are the little blue doohickies. Try AUDIOCAP PPT THETA .010uF-600V FILM/FOIL CAPACITOR (http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=027-700) in their place. These caps sound fantastic biased (charge-coupled) or un-biased. Buy a few and try them before buying a whole bunch.

[CLASS A]

Originally posted by Giskard
The bypass caps are the little blue doohickies. Try AUDIOCAP PPT THETA .010uF-600V FILM/FOIL CAPACITOR (http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=027-700) in their place. These caps sound fantastic biased (charge-coupled) or un-biased. Buy a few and try them before buying a whole bunch.

Thanks for that. Are the blue doohickies you are refering to are the tiny blue capacitors on pic 2 underneath side between the bigger blue capacitors?. What improvement can I expect?.

[CLASS A]

Has anyone got a copy of the cross over network diagram of the JBL 250Ti jubilee or where I can download one from.
Thanks

[Earl K]

Hi

Has anyone got a copy of the cross over network diagram of the JBL 250Ti jubilee or where I can download one from.

Well I haven't come across one. You might have to reverse engineer that circuit board backwards from the accompanying internal wires .


What improvement can I expect?

If you swap out all those big blue electrolytic caps for the "Film & Foil" types that Giskard has recommended - you'll significantly increase the ability of your speakers to produce a deeper , more defined sound-stage. Of course, there are a lot of other parts to your system that contribute to this area - as well as the acoustics of your listening area .

I've never seen the inside of one of those crossovers before and I must say that I'm somewhat shocked at the quantity of electrolytics populating that pictured circuit. I've played with DC biasing electrolytics as well as DC biasing great quality Polystyrene bypass caps. I've found that for my sonic purposes ( & with the electrolytics I've used ) that I need to use at least 50% of the final value from higher quality type caps when blending sounds into the base caps'( electrolytic ) signature sound, This ratio ( for me ) is the amount necessary to submerge the sonic signature of the electrolytic. IMHO, at a 50% ratio , there's just no economic advantage in maintaining any electrolytic caps within the series portion of the circuit .

So:

Start with replacing the caps found in the four circuits that are in series with the drivers. If the cost of film & foil types is prohibitive then buy some decent metallized polypropylene types ( Solen 250 volt types can work ). You'll want to do as Giskard has suggested and "Bypass" these Solens with small value Polypropylene film & foil types . If using Solens I prefer to multiply Greg Timbers suggested "Bypass Formulas" by a factor of 10. That means instead of .01uf I'd use a .1uf film & foil Polypropylene. I also bypass all bypass caps with Polystyrenes. As Giskard has stated numerous times - these put the "air" back into the soundstage. This air can be squeezed out by all caps. I use polystyrenes to "taste" - meaning that they can have so much "air" that they can be used to effectively "blunt" the knife-like edge that a lot of cheaper metallized polypropylene carry as a sonic signature . Effective values end up being equal to or greater than the .1uf mentioned for film & foil Polypropylene bypass caps .



- What are the markings found on those large blue "Elna" caps ?

- Also, the small blue bypass caps - Are they marked as MKP or MKT or something else ?


<> Earl K

[CLASS A]

EARL k
Thanks for all that info, I will have to take the network out again tomorrow to find out the values of the capacitors for you.
I have owned a pair of Kef R105/3 before the jubilee and exchanged all of the capacitors to supersounds and hoveland musicap ( treble) and the result was outstanding.
One concern about tackerling the jubilee is that the cross over network board is small and I might run into space problems if fitting the large in size capacitors.
Thanks

[Earl K]

Hi CLASS A,

Before deciding on what brand of Film & Foil polypropylene to buy, give the info gathering/opinion process a bit of time to see if anyone weighs in with an experience about DC biasing "Hovlands".

My intuition is that they are already "too long" physically & more importantly too long electrically - placed "end to end" to meet an as yet " inarticulated" criteria for "DC Biasing" .

***One reason capacitors can sound different is the physical ratio of length to width ( among many, many other factors ) .***

<> Earl K

[dieterj]

Originally posted by CLASS A
Dear all
I have recieved my pair of 250 ti jubilee last week and absolutly over the moon with them. My concern is regarding the stability of the speakers. I have concret floor with carpet and as the speakers only have round metal feets, they rock about when I gently push them. I m sure there must be a better solution to get them sitting firm. Unfortuneatly, there is no way to remove the round feets, I have taken out the cross over to look inside and there are no screws attaching the feets within. Have any of you got a better solution to stabilize the speakers.
I have also noticed with I took the cross over out to realise the capacitors used are of low grade quality ( elna ) blue in color. Has anyone used better quality capacitors and of what make.
Thanks in advance.

[CLASS A]

Originally posted by dieterj


thanks for that dieterj.
I have noticed there is another platform underneath the speakers in the same diemention and colour to the piano black. Please tell me how did you achieve that and are the spikes screwed into the bottom platform?.
thanks

[dieterj]

Originally posted by CLASS A
Dear all
I have recieved my pair of 250 ti jubilee last week and absolutly over the moon with them. My concern is regarding the stability of the speakers. I have concret floor with carpet and as the speakers only have round metal feets, they rock about when I gently push them. I m sure there must be a better solution to get them sitting firm.
Thanks in advance.
Hello Class A,
I've put 1 inch MDF Board under my 250ti for better sitting.
Can you post, what's the difference in Sound, when you change
some Capacitors?

Regards
Dieter

[CLASS A]

Originally posted by dieterj
Hello Class A,
I've put 1 inch MDF Board under my 250ti for better sitting.
Can you post, what's the difference in Sound, when you change
some Capacitors?

Regards
Dieter

Dieter
Do you own the jubilee?. the cross over network are different on the jubilee compare to all the rest of the 250ti. There is a 9V battery connection in the jubilee network for the capacitors. How did you get the piano black finish on the 1 inch MDF board?.
Cheers

[dieterj]

Hello ClassA,
I've also the 250ti jubilee with the 9Volt Batterie.
The MDF Board is not in the same Piano Lack.
It's a normal black glance Lack.
The Spikes're sitting in T-Nuts.
Now, i'm little bit confused about the Crossover, because i can't understand,
why Jbl put this cheap capacitors into?!
The Jubilee was not a cheap Box.
But i think the Sound now with the original crossoverparts isn't realy bad.

Dieter :confused:

[CLASS A]

Originally posted by dieterj
Hello ClassA,
I've also the 250ti jubilee with the 9Volt Batterie.
The MDF Board is not in the same Piano Lack.
It's a normal black glance Lack.
The Spikes're sitting in T-Nuts.
Now, i'm little bit confused about the Crossover, because i can't understand,
why Jbl put this cheap capacitors into?!
The Jubilee was not a cheap Box.
But i think the Sound now with the original crossoverparts isn't realy bad.

Dieter :confused:

I had a shock too when I took out the cross over to find very cheap capacitors used. They can be improved dramatically as I have proven when I changed high grade capacitors into my kef R105/3. I will keep you informed which capacitors used and end result of it all.
I must admit that the sound from the jubilees are great in stadard form.
What front end and ampification are you using to drive the jubilees?. I m using Sony SCD-1, Plinius M8 pre and Plinius SA250IV power ( 250w x2 in class A ).
Cheers

[4313B]

"Now, i'm little bit confused about the Crossover, because i can't understand, why Jbl put this cheap capacitors into?!"

Size and cost constraints. The bypass capacitors improve the performance of the cheap main capacitors.

"But i think the Sound now with the original crossoverparts isn't realy bad."

Nope, it shouldn't be.

[4313B]

"I will keep you informed which capacitors used and end result of it all."

Yes, the various types of capacitors can have dramatic effects on the stock systems. Sometimes the effects are less than desirable and sometimes they are significantly better.

[4313B]

0.01 uF RelCap Polystyrene and Foil - excellent depth
0.01 uF AudioCap Polypropylene and Foil - excellent attack and decay
24 uF SoniCap
stock 32 uF NPE as used in a "typical" JBL network

SoniCaps don't require bypass capacitors or biasing and they are very expensive.

The stock NPE and Mylar (Polyester) JBL capacitors benefit from both bypassing and biasing.

[Zilch]

I'd take one look at those crossovers having what appears to be about 20 nonpolar electrolytics each on them, bypass capacitors already in place, and 9V biasing as well, and my subjective assessment that the systems sound damn fine just as they are, and assume that JBL knew plenty well what they were doing there.

Another project for another day, I might build my own hot-rodded crossovers separately and keep the originals intact so that my ill-conceived blunders are reversible. A premium limited-edition system like that is not gonna resell as well with the disclosure that the owner has "customized" the stock crossovers.

Maybe I'd concentrate on figuring out how the feet are attached, instead, though there's a contradiction inherent between spikes and concrete floors. There seems little point in merely snagging the carpet backing.

Your mileage may vary....

[dieterj]

Originally posted by Giskard
0.01 uF RelCap Polystyrene and Foil - excellent depth
0.01 uF AudioCap Polypropylene and Foil - excellent attack and decay
24 uF SoniCap
stock 32 uF NPE as used in a "typical" JBL network

SoniCaps don't require bypass capacitors or biasing and they are very expensive.

The stock NPE and Mylar (Polyester) JBL capacitors benefit from both bypassing and biasing.
Thanks Giskard, very interesting.
Would you change only the Bypasscaps?

You're always the Men for Jbl:D

[4313B]

"I'd take one look at those crossovers having what appears to be about 20 bipolar electrolytics each on them, bypass capacitors already in place, and 9V biasing, and my subjective assessment that the systems sound damn fine just as they are, and assume that JBL knew plenty well what they were doing there."

Yes... what we do at home stays at home. :p
There is quite a difference in what we run at home versus what ends up in production...

[CLASS A]

Originally posted by Giskard
"I'd take one look at those crossovers having what appears to be about 20 bipolar electrolytics each on them, bypass capacitors already in place, and 9V biasing, and my subjective assessment that the systems sound damn fine just as they are, and assume that JBL knew plenty well what they were doing there."

Yes... what we do at home stays at home. :p
There is quite a difference in what we run at home versus what ends up in production...

you are absolutly right. should I stay with the same values as the standard on the bypass capacitors. I live in the uk and I cant find or source the audiocaps, can you recommend a different make. i believe I m the only 2nd proud owner of the jubilee in whole of UK.
Thanks

[4313B]

Originally posted by dieterj
Thanks Giskard, very interesting.
Would you change only the Bypasscaps?Tough call.

Changing the stock metallized polystyrene and metallized polypropylene capacitors to film and foil types can make a pleasant difference. It is the "cheapest" way to go and the least invasive. If one is careful they can easily reverse the procedure should they wish to do so.

Normally I don't mess with any of the larger networks such as the 250Ti or XPL200A. I just take them out, put them in a box, and start from scratch.

For instance, when G.T. first modified an original stock 250Ti with all biased Solen capacitors he ended up with a massive headache trying to work the extra, and physically larger, capacitors into the stock boards. Starting from scratch ends up being the way to go.

Biasing the NPE capacitors, which JBL has already done for you in the Jubilee, goes a long way in improving their performance. In the case of the new SK2-1000, which is meant to mount behind a perforated screen, JBL used all high quality, non-biased, capacitors because of the problems associated with battery changes. This system is designed and voiced to be the center channel for a pair of K2-S9800 loudspeakers. The non-biased high quality capacitors had to have very similar sonic character to the biased mylar and NPE capacitors which are bypassed with metalized polystyrene capacitors in the K2-S9800. Not a small feat.

Again, I have to warn anyone who wants to start modifying stock filters that JBL does extensive listening evaluations of their systems and changing capacitor dielectrics or inductor DCR values from stock can yield really good results as well as really bad results.

[CLASS A]

Originally posted by Zilch
I'd take one look at those crossovers having what appears to be about 20 nonpolar electrolytics each on them, bypass capacitors already in place, and 9V biasing as well, and my subjective assessment that the systems sound damn fine just as they are, and assume that JBL knew plenty well what they were doing there.

Another project for another day, I might build my own hot-rodded crossovers separately and keep the originals intact so that my ill-conceived blunders are reversible. A premium limited-edition system like that is not gonna resell as well with the disclosure that the owner has "customized" the stock crossovers.

Maybe I'd concentrate on figuring out how the feet are attached, instead, though there's a contradiction inherent between spikes and concrete floors. There seems little point in merely snagging the carpet backing.

Thanks mate
What other solution would you recommend instead of spikes?. I planning to attach 25mm wide spikes to the original feets as I have tried again to figure out how the feets are attached ( no luck. Cheers

Your mileage may vary....

[dieterj]

Originally posted by CLASS A
I had a shock too when I took out the cross over to find very cheap capacitors used. They can be improved dramatically as I have proven when I changed high grade capacitors into my kef R105/3. I will keep you informed which capacitors used and end result of it all.
I must admit that the sound from the jubilees are great in stadard form.
What front end and ampification are you using to drive the jubilees?. I m using Sony SCD-1, Plinius M8 pre and Plinius SA250IV power ( 250w x2 in class A ).
Cheers
My Electronic :
Linn Karik/Numerik - Cd
Audio Research SP16 - Pre
Crown Studio Reference 2 - Power

[CLASS A]

[QUOTE]Originally posted by Zilch
[B]I'd take one look at those crossovers having what appears to be about 20 nonpolar electrolytics each on them, bypass capacitors already in place, and 9V biasing as well, and my subjective assessment that the systems sound damn fine just as they are, and assume that JBL knew plenty well what they were doing there.

Another project for another day, I might build my own hot-rodded crossovers separately and keep the originals intact so that my ill-conceived blunders are reversible. A premium limited-edition system like that is not gonna resell as well with the disclosure that the owner has "customized" the stock crossovers.

Maybe I'd concentrate on figuring out how the feet are attached, instead, though there's a contradiction inherent between spikes and concrete floors. There seems little point in merely snagging the carpet backing.

Thanks mate
What other solution would you recommend instead of spikes?. I planning to attach 25mm wide spikes to the original feets as I have tried again to figure out how the feets are attached ( no luck. Cheers

[4313B]

"I've found that for my sonic purposes ( & with the electrolytics I've used ) that I need to use at least 50% of the final value from higher quality type caps when blending sounds into the base caps'( electrolytic ) signature sound, This ratio ( for me ) is the amount necessary to submerge the sonic signature of the electrolytic. IMHO, at a 50% ratio , there's just no economic advantage in maintaining any electrolytic caps within the series portion of the circuit ."

"Start with replacing the caps found in the four circuits that are in series with the drivers. If the cost of film & foil types is prohibitive then buy some decent metallized polypropylene types ( Solen 250 volt types can work ). You'll want to do as Giskard has suggested and "Bypass" these Solens with small value Polypropylene film & foil types . If using Solens I prefer to multiply Greg Timbers suggested "Bypass Formulas" by a factor of 10. That means instead of .01uf I'd use a .1uf film & foil Polypropylene. I also bypass all bypass caps with Polystyrenes. As Giskard has stated numerous times - these put the "air" back into the soundstage. This air can be squeezed out by all caps. I use polystyrenes to "taste" - meaning that they can have so much "air" that they can be used to effectively "blunt" the knife-like edge that a lot of cheaper metallized polypropylene carry as a sonic signature . Effective values end up being equal to or greater than the .1uf mentioned for film & foil Polypropylene bypass caps ."

Good points Earl! :) Interesting that you've found the order of magnitude necessary to blunt the metallized polypropylenes! I'll pass that along. :yes:

[dieterj]

Originally posted by Giskard
Tough call.

Changing the stock metallized polystyrene and metallized polypropylene capacitors to film and foil types can make a pleasant difference. It is the "cheapest" way to go and the least invasive. If one is careful they can easily reverse the procedure should they wish to do so.

Normally I don't mess with any of the larger networks such as the 250Ti or XPL200A. I just take them out, put them in a box, and start from scratch.

For instance, when G.T. first modified an original stock 250Ti with all biased Solen capacitors he ended up with a massive headache trying to work the extra, and physically larger, capacitors into the stock boards. Starting from scratch ends up being the way to go.

Biasing the NPE capacitors, which JBL has already done for you in the Jubilee, goes a long way in improving their performance. In the case of the new SK2-1000, which is meant to mount behind a perforated screen, JBL used all high quality, non-biased, capacitors because of the problems associated with battery changes. This system is designed and voiced to be the center channel for a pair of K2-S9800 loudspeakers. The non-biased high quality capacitors had to have very similar sonic character to the biased mylar and NPE capacitors which are bypassed with metalized polystyrene capacitors in the K2-S9800. Not a small feat.

Again, I have to warn anyone who wants to start modifying stock filters that JBL does extensive listening evaluations of their systems and changing capacitor dielectrics or inductor DCR values from stock can yield really good results as well as really bad results.
Thanks Giskard,
Now i think, that i stay with the original Crossover:confused:

[Zilch]

Originally posted by CLASS A

What other solution would you recommend instead of spikes?. I planning to attach 25mm wide spikes to the original feets as I have tried again to figure out how the feets are attached ( no luck. Cheers

If the pic that dieterj posted here is what you have, with screw-in adjustable feet, I'd simply unscrew them completely to remove them, leaving the threaded inserts in place, and see if setting the cabinets directly on the carpet improved the stability. They appear to be mounted near the edges already, so supplemental feet aren't going to help.

If that doesn't do it, consider two other options which come to mind:

a) Have much broader "pad" feet made to screw in where the originals came out, say, 4" diameter. They'll stick out beyond the base of the speakers, but may look good anyway, depending on the design. Think "moon pod."

b) Have machined supplemental sub-base plates of say, 1/2" to 1" heavy material such as stainless steel (expensive), or even thicker stone (cheaper) as a plinth under each speaker. Attach by through-bolting to where the original feet unscrewed, using the same bolt and thread size. If a thinner plate will do the job, attach using the original feet, even. These could be a very handsome modification. The purpose is to lower the center of gravity of the speakers by adding mass to the base, stabilizing them.

A significant feature of either of these approaches is that they may be removed and the original feet reinstalled later, if desired. No changes are made to the cabinets themselves....

[CLASS A]

Originally posted by Zilch
If the pic that dieterj posted here is what you have, with screw-in adjustable feet, I'd simply unscrew them completely to remove them, leaving the threaded inserts in place, and see if setting the cabinets directly on the carpet improved the stability. They appear to be mounted near the edges already, so supplemental feet aren't going to help.

If that didn't do it, consider two options which come to mind:

a) Have much broader "pad" feet made to screw in where the originals came out, say, 4" diameter. They'll stick out beyond the base of the speakers, but may look good anyway, depending on the design. Think "moon pod."

b) Have machined supplemental sub-base plates of say, 3/4" or 1" heavy material such as stainless steel (expensive), or even thicker stone (cheaper) as a plinth under each speaker. Attach by through-bolting to where the original feet unscrewed. These could be a very handsome modification. The purpose is to lower the center of gravity of the speakers by adding mass to the base, stabilizing them.

A significant feature of either of these approaches is that they may be removed and the original feet reinstalled later, if desired. No changes are made to the cabinets themselves....

Thanks for that...
I dont have the set up as dieterj. At the moment, the speakers are standing on their original feets and because it is on carpet, hence they are not stable. The original feets can be turned both ways but they dont extract from the base. I had a good look and feel inside of the base and do not notice anything attaching them from within. if only I can extract the original feets, then I may be able to attach heavy duty spike kits directly to it.
Cheers

[Zilch]

Do we have an exploded view of this or similar product showing how the stupid feet come off? Anybody have some 250Ti's?

In my exerience, what screws in usually screws out, as well.

Also, again, I don't understand what spike kits are going to do to help the situation on concrete, unless they are REALLY heavy spikes.

I'm just not getting this, apparently. :banghead:

[CLASS A]

Originally posted by Zilch
Do we have an exploded view of this or similar product showing how the stupid feet come off? Anybody have some 250Ti's?

In my exerience, what screws in usually screws out, as well.

Also, again, I don't understand what spike kits are going to do to help the situation on concrete, unless they are REALLY heavy spikes.

I'm just not getting this, apparently. :banghead:

sorry mate ( head fxxx)
I suppose I might have to use pliers to extract them if they dont turn out. Here are they spikes I m talking about.

[Zilch]

Originally posted by CLASS A
I suppose I might have to use pliers to extract them if they dont turn out.Yup. Sometimes the last few threads are intentionally deformed to prevent them from falling out.

Cool looking spikes, there! :)

[Earl K]

Hi CLASS A


-,,, the bypass capacitors . I live in the uk and I cant find or source the audiocaps, can you recommend a different make.

AudioCap is a trade name for a line of audiophile caps that are manufactured by RELIABLE CAPACITORS (http://www.capacitors.com/portals/product.html) . Their UK representative is "Audio Com" who can be emailed at [email protected] . Get them to quote some prices to you , including their delivery times . If it seems the caps having to be shipped out from California then consider checking out Parts Connexion (http://www.partsConneXion.com/) who sell Reliables' other 2 lines' of caps. These other 2 lines are "MultiCap" and "RelCap" . Parts Connexion is a Canadain eTailer ( Toronto based ) .

I'd be very wary of just replacing the bypass caps and expecting instantly positive results. For Instance; The reason I asked if the existing bypass caps were MKT or MKP ( or MKC ) is: If MKT was used , they would be present to blunt the edge or round out the typical "edgy" signature of the electrolytic. The necessity to include MKT would imply to me something about the sonic signature of the Elna(s). MKT , unfortunately doesn't offer great depth or resolution - just a "masked rounded" quality. MKT is Metallized Mylar ( MKP is metallized polypropylene & MKC is metallized polycarbonate ) . If MKP types are present , they would suggest that the DC-biased Elna(s) are not as edgy as most typical electrolytics. That would signal (me) that they might be able to be left intact with just higher quality Film & Foil bypasses shouldering the resolution burden. MKC has qualities that combine attributes from both MKT & MKP .

Base Caps - replacement

Space limitations could dictate that you might have to replace your electrolytics with "Metallized Polypropylene" caps . Smaller physical size was the driving force behind the development of all types of "metallized caps". Eliminating the separate foil layer ( by vapour depositing ) metal directly onto one or both surfaces of the plastic dielectric creates a "metallized" dielectric capacitor . Smaller size is the only "real" benefit for this type of cap. All the current cap makers are trying to construct MPP types that sound as good as a plain old "Film & Foil" types .

- Giskard has already recommended Solen - "Metallized" ( the second post of this thread) and then went on to later mention that the 250ti(s) developer ( from JBL ) has used Solens in his Charge Coupled Networks. Giskard has also stated that what is released to the public isn't necessarily what those who know better will use them themselves. Does more really need to be said on this ? I'd add, that you should stick with the smallest Solens available - the 250 volt variety . Also, I don't believe "Axion" MPP(s) will be much different with these transducers. I'd buy whatever type is most available to you.

<> Earl K

ps I wouldn't let all the recent "yellow-flags" over replacing your NP electrolytics deter you from pursuing better resolution.

[CLASS A]

Originally posted by Earl K
Hi CLASS A



AudioCap is a trade name for a line of audiophile caps that are manufactured by RELIABLE CAPACITORS (http://www.capacitors.com/portals/product.html) . Their UK representative is "Audio Com" who can be emailed at [email protected] . Get them to quote some prices to you , including their delivery times . If it seems the caps having to be shipped out from California then consider checking out Parts Connexion (http://www.partsConneXion.com/) who sell Reliables' other 2 lines' of caps. These other 2 lines are "MultiCap" and "RelCap" . Parts Connexion is a Canadain eTailer ( Toronto based ) .

I'd be very wary of just replacing the bypass caps and expecting instantly positive results. For Instance; The reason I asked if the existing bypass caps were MKT or MKP ( or MKC ) is: If MKT was used , they would be present to blunt the edge or round out the typical "edgy" signature of the electrolytic. The necessity to include MKT would imply to me something about the sonic signature of the Elna(s). MKT , unfortunately doesn't offer great depth or resolution - just a "masked rounded" quality. MKT is Metallized Mylar ( MKP is metallized polypropylene & MKC is metallized polycarbonate ) . If MKP types are present , they would suggest that the DC-biased Elna(s) are not as edgy as most typical electrolytics. That would signal (me) that they might be able to be left intact with just higher quality Film & Foil bypasses shouldering the resolution burden. MKC has qualities that combine attributes from both MKT & MKP .

[B] Base Caps - replacement

Space limitations could dictate that you might have to replace your electrolytics with "Metallized Polypropylene" caps . Smaller physical size was the driving force behind the development of all types of "metallized caps". Eliminating the separate foil layer ( by vapour depositing ) metal directly onto one or both surfaces of the plastic dielectric creates a "metallized" dielectric capacitor . Smaller size is the only "real" benefit for this type of cap. All the current cap makers are trying to construct MPP types that sound as good as a plain old "Film & Foil" types .

- Giskard has already recommended Solen - "Metallized" ( the second post of this thread) and then went on to later mention that the 250ti(s) developer ( from JBL ) has used Solens in his Charge Coupled Networks. Giskard has also stated that what is released to the public isn't necessarily what those who know better will use them themselves. Does more really need to be said on this ? I'd add, that you should stick with the smallest Solens available - the 250 volt variety . Also, I don't believe "Axion" MPP(s) will be much different with these transducers. I'd buy whatever type is most available to you.

<> Earl K

ps I wouldn't let all the recent "yellow-flags" over replacing your NP electrolytics deter you from pursuing better resolution.

Earl K
thanks for that, I have just had another look inside the network and found that the big blue capacitors have ELYTONE and are 100V np and the small ones have MPR .01K 250V CMC . with this information, would you still reecomend changing only the bypass capacitors and of what make and value. How many bypass capacitors are there within my network?.
Many thanks.

PS: where can I get my hands on the network diagram.

[Robh3606]

Hello Class A

I run an active set-up with a charge couple compensation on my horn compression driver combo. Very simple with my part count. I use Mylar and polpropylene bypass caps. Sounds to me like you have a bypassed Charge Couple network in place. If it were me I would leave well enough alone unless I could get a schematic to see what the deal is. You have to remember to run a charge coupled network you have to double the required capacitance and then add another cap so they are in series with a resistor going to that 9 volt battery. As you can imagine it is a very expensive way to do a network with high quality parts. Do you have a small 2 way set-up you can experiment on?? That would be a lot easier than trying to tackle a tweeked TOL 4 way design.


Rob:)

[Earl K]

Hmmm,

Went looking for the 250ti schematic and found this. The 250ti schematic is back there in the jungle somewhere - I saw it a couple of days ago . I'll post a link to it when I find it.

Giskard did up the following schematic a while back. It'll closely represent some portions of your network. It's obviously missing all the bypass caps plus it shows the "buss-strap type padding" that ( apparently ) your network lacks. But it's a great start. The main thing is that it gives you the idea of the size of the cap values you need. NOTE: since your (050 ? ) tweeter is different than the 044ti found in the 250ti - keep a lookout to see if the new tweeter warranted any network changes - inspect your existing caps to find out their values .


The numbers and lettering on the bypass caps mean little to me . I would start by replacing the caps in the UHF and HF section first . Leave the existing bypass caps in place. I'd focus on getting rid of the electrolytics first. If you can afford to do more then replace the Midrange caps followed by caps in the parralleled shunt circuits.

[CLASS A]

Originally posted by Earl K
Hmmm,

Went looking for the 250ti schematic and found this. The 250ti schematic is back there in the jungle somewhere - I saw it a couple of days ago . I'll post a link to it when I find it.

Giskard did up the following schematic a while back. It'll closely represent some portions of your network. It's obviously missing all the bypass caps plus it shows the "buss-strap type padding" that ( apparently ) your network lacks. But it's a great start. The main thing is that it gives you the idea of the size of the cap values you need. NOTE: since your (050 ? ) tweeter is different than the 044ti found in the 250ti - keep a lookout to see if the new tweeter warranted any network changes - inspect your existing caps to find out their values .


The numbers and lettering on the bypass caps mean little to me . I would start by replacing the caps in the UHF and HF section first . Leave the existing bypass caps in place. I'd focus on getting rid of the electrolytics first. If you can afford to do more then replace the Midrange caps followed by caps in the parralleled shunt circuits.
Thanks again Earl.....what brand of capacitors would you recomend in place of the electrolytic concidering I will fall into space problems if I go for the big ones. I have found two 250 network diagrams within the forum awhile ago, but I dont think they are the correct ones for the jubilee. Please have a look and give advice. Thanks

[CLASS A]

The second one.....

[Earl K]

Well, Just lost a fairly lengthy post into the ether . Oh well.

What caps? - Start with 250v Solens . They are decent, inexpensive metallized-polypropylenes. Hopefully they'll fit .

Have you taken measurements of the available space ?

I just looked at Solens' 2003 Cdn price list . Doing all 3 legs ( series caps ) will cost around $130.00 Cdn ( no tax , no shipping included ) .

Have you established a budget for this ?

<> Earl K

[CLASS A]

Earl
Thanks again, I have decided to go with the solen capacitors. Would you recommend using the solens for the bypassing too. I think I would keep the values of the bypass capacitors to the original value of 0.1 uf. This way, I m going to get the same kind of sound as original and hopfully much better in all areas.
Cheers

[Earl K]

Hi

I'd leave the existing bypass caps in for at least a month after putting the Solens in. If I figured there was something to be gained with new bypass caps - I would buy just what Giskard suggested at the beginning of this thread; Film & Foil Polypropylene "AudioCap" (s). If they aren't available then other makes will do the job - but that need is weeks away .

Giskard has mentioned this before and I'll reiterate it here. It takes some time for DC biased caps to "breakin" or get fully formed from the DC voltage. What one hears on day 1 of installation is quite different than what is heard a week later and then to a lesser extent 2 weeks later. I'm always suprised 10 days into the process at the sonic differences. I wait 3 weeks into a cap change to determine if I like the results. I routinely changein different cap combinations ( on a monthly basis - for the fun of it ) .

<> Earl K

[CLASS A]

Originally posted by Earl K
Hi

I'd leave the existing bypass caps in for at least a month after putting the Solens in. If I figured there was something to be gained with new bypass caps - I would buy just what Giskard suggested at the beginning of this thread; Film & Foil Polypropylene "AudioCap" (s). If they aren't available then other makes will do the job - but that need is weeks away .

Giskard has mentioned this before and I'll reiterate it here. It takes some time for DC biased caps to "breakin" or get fully formed from the DC voltage. What one hears on day 1 of installation is quite different than what is heard a week later and then to a lesser extent 2 weeks later. I'm always suprised 10 days into the process at the sonic differences. I wait 3 weeks into a cap change to determine if I like the results. I routinely changein different cap combinations ( on a monthly basis - for the fun of it ) .
Hi
Thanks Earl, I will take your advice to leave the bypass capacitors in for a monthe after changing the solens. How would I know if I need to change the bypass capacitors after the solens are in for a month?.
Cheers

<> Earl K

[CLASS A]

Earl

At what point after installing the solens do you know if changing the bypass capacitors are of benefit to the sound?. Are all of the bypass capacitors are of value 0.1uf?.
Cheers :)

[Earl K]

Hi CLASS A

I'd suggest you keep a small journal of your impressions of the sound of your speakers - when listening to some of your favourite music.

(A) Start with the way things sound like now.
(B) Then what your immediate impressions are after putting in the Solens
(C) Your impressions 1 week after installing the Solens
(D) Your impressions 2 weeks after putting in the Solens
(E) Your impressions 3 weeks after installing Solens
(F) 3 - 4 weeks after (Solen) installation remove the Bypass caps in the UHF & HF portions of the circuit & record your listening impressions . This should give you & others (like me) some clues as to just what nuances your existing bypass caps contribute to the overall sound. Then we can revisit this subject once you have some of your own impressions.

BTW ; I think you said your existing bypass cap values are .01 uf - so stick with those values if you ever change them out .

<. Earl K

[CLASS A]

Earl
Thanks a million for all your advice. I will let you know how I get on with the change of capacitors. I have e mailed JBL requesting for the network diagram, its a shot in the dark but had to try.
Cheers

[250Ti only]

I too am looking to upgrade the over 20 year old caps in my 250Ti's.
Cost for the "best" caps is not an issue for me. I want to go for the gold:D , I'm not getting any younger and listening to music is my 'BIG" hobby.
I bought my 250Ti's new--(upgading from my previous "QUAD" electostatics), and I figure I already have more than my moneys worth in listening pleasure.
Particularly since the upgrades I have done have just made them sweeter, more detailed, more dynamic and seemingly more powerful!!
I drive them with 200 watt Spectral amps through MIT Reference cables. And a lot of MIT's very best in AC conditioning-which alone has made a staggering improvement !!
If you haven't heard your 250's with absolutely top class AC conditioning- take heart- your speaker can sound TWICE as good as you've ever heard it without doing anything else!!The sound is "stunning" now according to all who hear them-but, I know they can still be improved-- since there must have been ""huge"" improvements in caps in the last 20 years.
I don't care if I have to buy Solen or Mundorff or ???--just please someone say what is the best BEST they have heard or can think of or let me know if I can just order identical value replacements from a manufacturer.
What would a 250Ti lover want to upgrade them with?
:) :) :) :) :) :)

[CLASS A]

250ti only

I have not had the chance to upgrade the capacitors in my 250ti jubilee's. One look into my cross over scares me in tackling the job since the lack of room. However, you have alot of room in your 250ti cross over board, I would change all to solens with the same values as factory for big improvements.
What upgrades did you proform on your 250's.
Cheers