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Green Wagon

JBL 4411 - Refresh.

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Yay another speaker. I like doing speakers.

 

Not much to say for a change :D

Remove original crossover, make new one with waaaaay better parts.

And wire it up with customer supplied cables and binding posts.

 

JBL 4411

 

post-106429-0-19219100-1466759413_thumb.

 

The wax coils and some resistors were changed from what you see in this box. Typical JBL schema being wrong compared to what is actually used.

Missing decimal places, wrong decimal places, unspecified parts. Would've sounded like poo if I hadn't checked the old crossovers and made some correction.

47ohm resistors feeding the mid were actually 4.7ohm.

0.08mH series inductor was really a 0.8mH inductor.

An unmarked resistor was a 7.5ohm across the tweeter.

And finally, the tweeter was drawn in phase when it isn't (18db tweeter xover).

 

post-106429-0-27621800-1466759436_thumb.

 

post-106429-0-47370100-1466759447_thumb.

 

post-106429-0-93985300-1466759425_thumb.

 

post-106429-0-62188800-1466759459_thumb.

 

post-106429-0-66513400-1466759468_thumb.

 

post-106429-0-22504400-1466759483_thumb.

 

post-106429-0-26862100-1466759494_thumb.

 

post-106429-0-37194400-1466759504_thumb.

 

post-106429-0-54483500-1466759512_thumb.

 

Can't say what they sounded like before. Didn't try them (Couldn't be bother rootin around with stupid JBL push connectors).

But they sound pretty nice now.

Once the owner gets them back he might post his thoughts.....

 

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Wish mine was that neat @@Green Wagon, mine looks like i though a heap of parts into a bucket of solider. I have never been one for neatness. 

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What are the speakers behind the jbl?

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Wish mine was that neat @@Green Wagon, mine looks like i though a heap of parts into a bucket of solider. I have never been one for neatness. 

 

Ta.

LOL.

I have seen some that should be put to death ;)

I really hate to tell you this, but every time I do/redo a crossover neater and soldered properly, it actually does improve the sound.

I have no theory as to why. But others come to the same conclusion after independent listening..

 

What are the speakers behind the jbl?

 

My babies.

Troels Jenzen D's.

http://www.stereo.net.au/forums/index.php/topic/63963-troels-gravesens-jenzen-d-mk2-speakers-finished-d

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Timely as I have begun the investigation process of potentially upgrading the crossover of my JBL 4435's so am keen on hearing the owners thoughts on the upgrade.

 

Heres a list of what ive come up with so far....

 

Description

QTY

10W Superes 56 Ohm (R6,7,8,9)

6

10W Superes 82 Ohm (R6,7,8,9)

2

10W Superes 5.1 Ohm (R1)

2

10W Superes 10 Ohm (R4,R5)

6

Superior Z-Cap 15uF (C3,C13)

4

 Superior Z-Cap 12uF (C11)

2

Superior Z-Cap 1.5uF (C9)

2

Superior Z-Cap 1uF (C9)

2

Air-Core 2.7mH 14AWG (wound back to 2.6mh) (L102)

2

Air-Core 1.25mH 15AWG (wound back to 1mh) (L2)

2

Air-Core 0.4mH (L1)

2

 

 

Still need another 2x 18mh inductors for the bass driver but cannot find them listed.

 

Aint gonna be cheap as the above parts are already pushing close to $800 as it is...

4435lr.pdf

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Have you considered biasing/charge coupling the 4435s?

 

It would be a worthwhile upgrade and it is universally agreed that it is an upgrade over the original crossover. Plenty of reading at the Lansing Heritage forums.

 

If I was to have the crossovers rebuilt for a speaker like the 4435's I would do it once and do it right.

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The next lot of crossovers Nigel will be building me will be charge coupled 250TI's, while I am there I will get Nigel to rewire the speakers with newer thicker gauge hook up wire.

 

I am expecting around $1300 in parts.

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Timely as I have begun the investigation process of potentially upgrading the crossover of my JBL 4435's so am keen on hearing the owners thoughts on the upgrade.

 

Heres a list of what ive come up with so far....

 

Description

QTY

10W Superes 56 Ohm (R6,7,8,9)

6

10W Superes 82 Ohm (R6,7,8,9)

2

10W Superes 5.1 Ohm (R1)

2

10W Superes 10 Ohm (R4,R5)

6

Superior Z-Cap 15uF (C3,C13)

4

 Superior Z-Cap 12uF (C11)

2

Superior Z-Cap 1.5uF (C9)

2

Superior Z-Cap 1uF (C9)

2

Air-Core 2.7mH 14AWG (wound back to 2.6mh) (L102)

2

Air-Core 1.25mH 15AWG (wound back to 1mh) (L2)

2

Air-Core 0.4mH (L1)

2

 

 

Still need another 2x 18mh inductors for the bass driver but cannot find them listed.

 

Aint gonna be cheap as the above parts are already pushing close to $800 as it is...

 

2.7 -> 2.6, doubt youd hear/measure any difference but thats not a problem, more than happy to do that for you. :)

 

1mh 15awg air

http://speakerbug.com.au/index.php?route=product/product&path=18_46&product_id=366&limit=75

 

For high values go p-core.

http://speakerbug.com.au/index.php?route=product/product&path=18_45&product_id=295

 

Another option for that value is the toriodal C-cores.

More expensive, but the dcr is a fraction of the pcores. ~1 ohm vs ~0.2 Ohm

 

Interesting side note, Jantzen have previously supplied JBL with inductors (both air and p-core).

 

The xovers in my speakers came to about 1,400. But that was before I owned speakerbug. Can you say, DOHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH :D

 

Anyway, pm me when your ready and well talk ;)

 

Have you considered biasing/charge coupling the 4435s?

 

It would be a worthwhile upgrade and it is universally agreed that it is an upgrade over the original crossover. Plenty of reading at the Lansing Heritage forums.

 

If I was to have the crossovers rebuilt for a speaker like the 4435's I would do it once and do it right.

 

Mm yes. You really love your Charge coupled don't you :D

Might want to explain that you double the number of caps and their values.

I know you chose the cheaper crosscaps.

I'd love to know what using superior caps in that would be like.....

 

 

 

I'm bashing through some music to break in the new parts on these 4411's.

Mmm. I like.

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4435.

 

L1 - schema has it listed as 0.04 - You say 0.4 ????????????

Knowing what jbl can be like, I'd be tempted to pull and measure it and make 100% of the value 

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Mm yes. You really love your Charge coupled don't you :D

Might want to explain that you double the number of caps and their values.

I know you chose the cheaper crosscaps.

I'd love to know what using superior caps in that would be like.....

 

 

 

I'm bashing through some music to break in the new parts on these 4411's.

Mmm. I like.

 

Yes I suppose I do, only because people with far more knowledge than I and also who have experience with the crossovers prefer them.

 

Even Greg Timbers prefers the CC'd crossover and was amazed at the difference between the stock 250TI and the CC'd ones.

 

I recently started a thread on Lansing Heritage forums asking if there was any merit to biasing the crossovers when we now have access to such exotic components.

 

Here are a few quotes from the resident guru there who is personal friends with Greg Timbers:

 

Greg told me a few years ago - "I don't even bother wasting my time listening to unbiased networks anymore." Yeah, I get what he is saying.

Unfortunately I have wasted my time listening to unbiased networks and I prefer biased. I even biased my Tannoy networks. That was a hoot and a holler! yesnod.gif

But... I also have first hand experience in biasing 250Ti's and to me it is a real PITA so I can certainly understand any hesitation taking on the task. You couldn't pay me enough money to build another pair of biased 250Ti networks.

 

Regarding the 4411's, they are excellent speakers and certainly stand out amongst the older JBL's. They are a very special pair. The same engineer who designed the 4435/4430 designed the 4411's as well, David Smith.

 

Greg Timbers designed the crossovers for the 4435's.

 

edit: I should also add that CC'd crossovers are of most benefit to compression drivers and I personally would not have worried about biasing the 4411's.

Edited by kelossus

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But... I also have first hand experience in biasing 250Ti's and to me it is a real PITA so I can certainly understand any hesitation taking on the task. You couldn't pay me enough money to build another pair of biased 250Ti networks.

 

 

 

Riiiiiiiiiiiiiight.

Soooo, should I move this week and not leave a forwarding address  ???????? :D

 

But, it all raises the interesting question.

 

We know what an improvement the superior caps are over the cross caps, and you know what your L212's sound like with the charge coupled cross caps.

So, I wonder. What would happen with a charge coupled superior cap version ?

Other than you going bankrupt that is :)

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Riiiiiiiiiiiiiight.

Soooo, should I move this week and not leave a forwarding address  ???????? :D

 

But, it all raises the interesting question.

 

We know what an improvement the superior caps are over the cross caps, and you know what your L212's sound like with the charge coupled cross caps.

So, I wonder. What would happen with a charge coupled superior cap version ?

Other than you going bankrupt that is :)

 

That would cost serious money, it would scare me to price them up and it would end up being close to the amount I paid for the 250TI's. I would rather spend some extra dollars on wax coils.

 

For those who are wondering what biased networks are here is a post from Greg Timbers on the forums explaining a little bit regarding them:

 

"The capacitor biasing is something that has existed for many years. Tube equipment does it automatically since there is usually a large DC offset between stages. Some early transistor amps/preamps had two polarized caps in series with the center point going to ground through a large resistor.

I personally became aware of this technique for speaker systems through communications with Ed Meitner, currently of EMM Labs. He is a wealth of information regarding these "tricks" to help linearize or improve the sound of passive components.

It turns out that the bias trick actually increases measured IM distortion and the higher the bias voltage, the greater the increase. It is not by a great amount, but it is measureable. The sound imporvement (or change) is very rarely perceived as worse and is never linked with a increase in IM distortion. The sonic effect is one of smoothness, increased spaciallity, detail and stuff like that. IM has a muddling or confusing effect so I doubt that this particular steady state measurement is explaining the sound difference either way.

Simply put, we are striving to create a class A situation but as was just pointed out, depending on the bias voltage with respect to the voltage across the capacitor, we may only have an "A" condition up to a particular drive level. So if it makes you happier, consider the change to be class AB, but heavily biased to A. You must also keep in mind that the voltage across the input terminals of the crossover network does not tell you what voltage or current is applied to any individual component. Some parts block signal and others shunt signal so the loading on a particular part is not obvious. For the most part, the caps are well taken care of with 9 volts, even at healthy drive levels. The obvious choice for 9 volts is the small cheap battery and holders that are available. No current is involved so a smoke detector battery and holder is a natural choice.

We did do one system with 18 v (M9500). Certain of the Japanese reviewers thought it was an improvement. I can't personally tell any difference. I am also told on a regualr basis (again by our Asian customers) that the battery must be changed at least every 90 days and that the sound degrades after that. Once again, I have not been able to "hear" any difference after 90 days and the battery is certainly still good for many years from a voltage standpoint.

What playing around I have done with initial application of a battery to a biased circuit (that has not been previously powered up) is that it takes about 3-5 seconds for the soundstage to change. I have tried to measure the voltage level in that time period and it seems that several volts is all that is necessary to accomplish 90% or more of the improvement. Once a circuit has been energized, it is nearly impossible to return it to zero. You have to individually short out each cap and leave them shorted for a while or else they will creep back up somewhat. If you replace the battery with a short and play the system for a while, the caps will start to bias themselves, although not to anywhere near the same degree.

You can take this opinion for what it has cost you. I have been very pleased with biasing for many years. I use it in all applications that involve a capacitor and I have rarely been disappointed. Results may vary so if it doesn't do it for you that is okay too. It cost a bloody fortune to implement as it requires 4 times the capacitance and double the capacitor parts count. The network size gets huge as well. Inspite of this, I have never heard a capacitor type that didn't improve (or change) including the nearly perfect teflon variety."

Edited by kelossus

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But, It's not my money im offering to spend :P

 

Thanks for the explain a post from Greg.

 

What I think should be said here is that even though you do double the cap values and parts count, we don't know if this then means you don't need the expensive caps to achieve the same result.

So the extra bigger parts could be offset by using cheaper parts to start with...

 

Oh so many holes for the rabbits to hide in...........

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Good work Nigel

I still think that the crossovers you built for me are the sexiest so far ( we won't talk about cost )

And they have made my system sound superb

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Thanks all, yes I did think about charge coupling but frankly for me the expense of not only doubling my cap count but also doubling there values means its off the table.

 

Good pickup on the 0,04mh Green Wagon, next time ill wear some glasses when reading the schematic  :P One other  thing the guys bang on about in the JBL forum when doing crossover upgrades is the importance of DCR matching on the coils to the point where some are adding additional series resistance when replacing the inductor to match the old value. How critical is this in your opinion?

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Thanks all, yes I did think about charge coupling but frankly for me the expense of not only doubling my cap count but also doubling there values means its off the table.

 

Good pickup on the 0,04mh Green Wagon, next time ill wear some glasses when reading the schematic  :P One other  thing the guys bang on about in the JBL forum when doing crossover upgrades is the importance of DCR matching on the coils to the point where some are adding additional series resistance when replacing the inductor to match the old value. How critical is this in your opinion?

 

If you use a cheaper capacitor like the crosscap it actually works out around the same money. Thats one of the theories behind biasing is once the voltage is applied the sonic signature of the capacitor isn't as important.

 

Either way freshening up the crossovers will be a worthwhile investment and I wish you the best.

 

Regarding the DCR, Nigel will explain the technical/functional reason for it but it is important. Where there has been high DCR's Nigel has added a resistor in series as you mentioned.

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Good work Nigel

I still think that the crossovers you built for me are the sexiest so far ( we won't talk about cost )

And they have made my system sound superb

 

Sexiest or biggest ?

Either way its a toss up between yours and Steve's. :)

 

 

Thanks all, yes I did think about charge coupling but frankly for me the expense of not only doubling my cap count but also doubling there values means its off the table.

 

Good pickup on the 0,04mh Green Wagon, next time ill wear some glasses when reading the schematic  :P One other  thing the guys bang on about in the JBL forum when doing crossover upgrades is the importance of DCR matching on the coils to the point where some are adding additional series resistance when replacing the inductor to match the old value. How critical is this in your opinion?

 

Yes, but, you could use the cheaper caps which would offset the cost.

When did Chris's L212 CC, I think the cost came out about the same as if he'd used more expensive parts.

But, another issue of CC is size. They will take up more real estate and may even be to big to fit in the original spot.

 

The values for the 4435, I'd still pull the crossovers apart and measure value (and dcr) of each coil.

I have seen JBL change revision through a models life and some are big changes. Chris's L212's had two different crossovers, from the factory. And theres three revisions.

 

Values and DCR etc. Thats not an easy one to answer.

Some parts will drift with age, and you get used to how they sound with 'Not correct' values. So you swap in parts with 'correct' values and it sounds different.

But, who says the original part was the right value to start with ? Technology has come foward a fair way in production and tolerance.

 

Capacitors used to be quoted as anything out to +/- 25%

Most caps these days (for xovers) are 5% at worst

And yes caps (mostly electrolytic's) have DCR and inductance.

 

Inductors, well, how were they designed, how were they made, and at what frequency were they measured ?

The meter I use has 5 selectable frequencies from 100hz up to 100Khz.

The measured value can change dramatically with the used frequency.

 

The DCR of an inductor will alter it's Q. That is the range over which it operates.

This is normally only a big issue for notch filters when your trying to correct a spike in response.

If it's a big narrow spike, you dont want to pull down that whole area, just that narrow spike. That's when you need to get the dcr right.

 

I find the bass inductor usually benefits from being a lower DCR. Bass seems to tighten up and become, I'd say more pleasing to listen too.

I don't say it's correct, but it sounds nicer.

 

Older JBL's are I think more tolerant of differences in xover values due to there inherent smoother responses (15" drivers that go out to several Khz without major break up ?)

Some of the new modern drivers have spikes etc that really do need exact filters.

 

Having said all that.

Personally I think +/- 10% is a good fuzzy area to aim for.

So much to look at with speakers.

Age and compliance change in surrounds and spiders, Magnet Gauss, age and absorption of the wadding (if there is any), condition of the voice coil, ambient temperature....

 

And lets not forget the squishy interface.

That all important single piece that can be fooled by mere suggestion.

The human brain.

 

If it sounds better to you. Be happy. If this is the biggest thing in life you have to stress over. I envy you :D

 

If you use a cheaper capacitor like the crosscap it actually works out around the same money. Thats one of the theories behind biasing is once the voltage is applied the sonic signature of the capacitor isn't as important.

 

Either way freshening up the crossovers will be a worthwhile investment and I wish you the best.

 

Regarding the DCR, Nigel will explain the technical/functional reason for it but it is important. Where there has been high DCR's Nigel has added a resistor in series as you mentioned.

 

 

Yup. I believe CC was an attempt to get away from non linearities of old wobbly cap construction.

I suspect it also means they could use less than ideal caps and still get far superior results.

So throw in some modern budget friendly caps that are far superior to olden day caps, and it has to be win win.

No I have no direct evidence of this.

Just a whole heap of little bits of proof from everywhere.

 

Yes in some xovers where the inductor dcr is stupidly high (like 5 or more ohms) I have thrown in a series resistor.

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^^^^

 

Mate thanks very much for such a detailed post,so much to ponder right now....

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No worries.

 

I should add this is just my thoughts and im more than sure that there are those here with a way better understanding that could explain things far better...

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These are my JBL 4411s which I bought from Chris(kelossus) in November 2015. Extremely well kept pair as I'm certain all his gear is.

I'm happy to report that Nigel's modifications have exceeded my expectations in every way.
He told me the job would take one month to complete.. it took just under one week!! And he replaced incorrect parts free of charge, lubed the hard to reach L-pads, and used some of his own wiring.
The speakers are over 30 years old, but the pulled crossovers look immaculate. Apparently the caps, inductors, and resistors were decent for their time, but doesn't really compare well against today's gear.

How does it sound?
Short version:
Worth every cent, sound has improved in every conceivable way.

Long version:
So much better it's stupid. I mean, I liked the stock standard. But to nitpick the highs sounded somewhat tinny and even noticeably grainy on some songs.. 

No longer.. highs are extended and resolving, mids are now seriously smooooth. Really loving it with high frequencies set a notch or so above default on the L-pad. Getting zero listener fatigue.. if anything I am listening too much right now.

 

When I went to pick them up, Nigel had them hooked up to his pass labs amp and the bass there was seismic. I thought the ass would drop out once I plugged them into my tube amp but I was presently surprised.
It definitely goes deeper. Where it used to be woolly, it's now tighter and better defined. Bass slam is especially satisfying.

Before the new networks ,I could sit there and with a little bit of effort, pick out the drivers.. you could actually hear the cut offs. The way they are now, even straining I can't tell. Just sounds like one continuous sound. 

Also, they feel like they weigh 5kgs more?! maybe I just need to hit the gym.

Thanks again to Nigel for all his help. I would definitely recommend it.

I don't have a new pic as the camera is out of order, but here they are before they were sent out.

post-144521-0-47071500-1467029764_thumb.

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More than welcome :)

 

Very glad they have met (and exceeded) your expectations.

I try to estimate longer than I need so that if (when ?) I get a job done sooner it comes as a nice suprise.

Plus I pushed hard to get them done so you could enjoy them during your break.

Yes once apart they looked almost new inside.

The original crossovers were very well made with what even today would be classed as overkill parts.

All film caps with small bypass caps, mostly cored inductors and wire wound resistors. No electrolytic's to be seen.

But modern tech has resulted in far better parts today.

 

Again, I say your welcome. ;)

 

I also have to say I really like your rack and speaker stands.

They blend with the equipment beautifully.

Little bit of modern and a little bit of old.

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Fantastic outcome guys, has really helped push this mod higher up my priority list.

 

Your original crossover looks very similar to mine    

post-122789-0-07670900-1467065644_thumb.

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Have a close look at the inductors.

That tells you what value they are.

 

Seems they are labeled with the 'R' as the decimal.

At least thats what I measured on these.

 

The .00R8 is a 0.8mh

The 01R0 is a 1mH

 

post-106429-0-99527500-1467080133_thumb.

 

 

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