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Tony
11-10-2008, 07:48 PM
I wonder if anyone can help with problems I am experiencing trying to bi-amp my 4430’s.

Until now I have been running my 4430’s passive through 2 x Naim 160 stereo amps using one channel for each speaker with very satisfactory results. Recently I have introduced the 5235 crossover with the special 4430/4435 network cards installed using the same two Naim 160 amps one for LF and one for HF and am now having problems.

My first impressions on bi-amping with the 5235 were positive finding the sound to be clearer with more definition and a wider soundstage :D. However, over the next few days I became aware of bias towards the left speaker – which, of course, I can bring back into balance with the pre-amp balance control. Trouble is the degree of slew seems inconsistent insofar that listening becomes ‘uncomfortable’ with the sense that the balance control must be re-adjusted sometimes even within the same track :screwy:. The was not necessary beforehand when running passive as described earlier, where the sound was very solidly centred - as it is now again as I have returned the system to run on the internal crossover.

It would seem that 5235 crossover and/or network cards are losing strength of signal somewhere. Or, I suppose it could be with those parts of the internal crossover which remain active when switching the 4430’s over to external crossover.

I am not very technical in these matters and undoubtedly will need to consult a specialist, but I wonder if anyone has had similar experiences or can otherwise suggest a probable cause and resolution?:thmbsup:

mvaldes
11-10-2008, 09:59 PM
Hi Tony,
I haven’t had any similar problem when biampling my 4430 with the 5235. I must also say that I used it for very short time because I don’t like how the 5235 “sound”, but this is just my opinion.
I suggest you to check the rotary bi-amp switch on the 4430 back. It is a very cheap switch that more than often do not provide a good contact, especially if it haven’t been used for long. (try to move it L and R for few times with the amps powered off)
Try also to check all the connection on the 5235, amps and speakers. It sound like you have a phase problem.

Hope this help

Michele

doodlebug
11-10-2008, 10:26 PM
Seems like there have been some other posts regarding issues with that internal/external switch on the 4430s. Might want to do a search here. I believe cleaning was the order of the day.

I'd like to think that would be a really cool setup.

Cheers,

David

JBL 4645
11-11-2008, 12:11 AM
Hi Tony,
I haven’t had any similar problem when biampling my 4430 with the 5235. I must also say that I used it for very short time because I don’t like how the 5235 “sound”, but this is just my opinion.
I suggest you to check the rotary bi-amp switch on the 4430 back. It is a very cheap switch that more than often do not provide a good contact, especially if it haven’t been used for long. (try to move it L and R for few times with the amps powered off)
Try also to check all the connection on the 5235, amps and speakers. It sound like you have a phase problem.

Hope this help

Michele

Yeah seems like its got dirt clogging it up. A little spray of (compressed air) might clear it, thou it only means the dirt will be moved to different part of the (variable resistor).

The idea with active crossover is lower lows and higher highs with less distortion.

Wow that a nice JBL speaker!:)

http://www.vintage-audio.com.ua/pict_mod/cat_items/397_pict_big_jbl_4430_b.jpg


Tony

Try this out get a sound pressure level metre and use (wideband pink noise) turn off or mute the LF and play the pink noise on each speaker at a single time left and then right! Note the level of each and if one is different adjust the level until each on has the same level on the SPL db metre.

Then mute the HF and test the LF for equal level and get them matched up to the same SPL db level and then play them back with LF and HF all turned on! Listen to some music or film soundtrack and see if that makes a difference.

Note: the hiss or whoosh sound on the HF should have the same tone place them as close together to see if they have the same tone it shouldn’t be like this. (Left hiss and right HISS wrong) if that helps? They should each have the same loudness (left HISS right HISS correct).

If they are spaced apart bare in mind the walls might be closer to one of the HF and if you make hiss sound with your mouth and place your hand in front and move it back and forth it will go whooshy!

I use Behringer DCX2496 on my JBL control 5 LCR and each is tested with HF and then LF to get the same level over the fronts I use a little delay on the centre channel this helps with half panned sounds on the left and right that partly mix into the centre, giving a wider sound image at the front.

Might be you rushed it with the JBL 5235 and don’t own an SPL db metre also an RTA will help to see the frequency response of each speaker in-turn, you might have dodgy HF or maybe a lose wire?

jblbgw_man
11-11-2008, 12:45 AM
Hey Tony,

Because I prefer the 4435 active mode over the passive mode I removed the changeover switch and hard wired it into the active mode ..... these switches really are suss and I believe this is most likley to be your problem.

As sugested elsewhere here check all your input connections to the 5235 for phase consistancy between L & R and speaker phase connections both from the amps and on the speakers.

After pulling my hair out for ages to get the LF & HF balance right I now set mine up using a 8 ohm dummy load on the output of each amp and a HP AC RMS Volt meter across that, setting up the amp gains and 5235 drives using a 80Hz tone for the LF and a 10kHz tone for the HF and matching the output RMS Volts across the dummy load........... works fine for me :bouncy:

grumpy
11-11-2008, 06:38 AM
... another vote for the input switch, but don't discount the possibility that you might need
to set the 5235 gain settings somewhat differently for the L and R channels..

Matching L/R HF outputs to less than 1dB requires measurement tools (as others have also
already suggested), and the adjustment was fairly sensitive (a small increment of
rotation produced a large change in gain... at least when looking for sub-dB changes).

boputnam
11-11-2008, 08:19 AM
Tony...

You've gotten a variety of opinions and advice - but one comment you made has me fishing:
...Trouble is the degree of slew seems inconsistent insofar that listening becomes ‘uncomfortable’ with the sense that the balance control must be re-adjusted sometimes even within the same track :screwy:. Uh, that is not good. I'm suspicious that good ol' 5235 is giving up the ghost, so to speak.

Who made the cards?
Where did you buy this from?

I'd suggest you get your hands on another active, adjustable, crossover. Set it's parameters to match the 5235 cards, and see if the symptoms persist. My grab is, the 5235 is past it's "use by date".

grumpy
11-11-2008, 09:00 AM
yeah... that comment was weird, but sometimes balance issues are just more noticeable
with certain material. One assumption I was making is that this balance issue wasn't a
problem before (e.g., not just an L-pad wiper problem... which I've had).

Were leads to the speakers swapped L<->R to see if the balance shifted the other way?
(isolate speaker problem from potential crossover/amp issue)

If levels are set, test material is mono, and the problem persists, then there's something to chase. :)

boputnam
11-11-2008, 09:05 AM
Hi, Dave...

Agreed. I'm relying upon his (near) closing comment: "The was not necessary beforehand when running passive as described earlier, where the sound was very solidly centred - as it is now again as I have returned the system to run on the internal crossover."

As usual, us JBL CSI'ers are held hostage to the limited available evidence offered... :p

Robh3606
11-11-2008, 09:14 AM
It it's limited to the HF of one side try running the potentiometer over it's full range a half dozen times. Could just be an oxidized pot. If you hear noise while you are adjusting the level good chance that could be it. Power it down when you run the pots through their ranges just to play it safe. When you bring it back up have the amps turned down too just in case.

Rob:)

Tony
11-11-2008, 11:44 AM
Hi and thank you everyone.

I do not have any equipment to take measurements - only my ears. I shall work through the suggestions beginning first with swopping speakers leads to see if I can isolate the problem to the crossover/network cards or the speakers. I hope I can establish this without having to shift the speakers around! I do not think the poweramps are the problem - the system is now set back to passive on internal crossover and is 'singing' with the soundstage solidly centred. In fact the sound is impressive (especially the the Boss's half-speed mastered Born to Run that I was playing last night) and I have no reason to think that any of the drivers are dicky.
I have two 5235 crossovers (but only one set of network cards) so I can possibly eliminate narrow-down another question. Phasing might be an issue as I had trouble having the interconnects made-up correctly - so there might be an issue here. What bugs me is that on first connecting up using the external crossover etc, I was not immediately aware of the imbalance and was initially impressed with what I thought was a step forward - but perhaps I heard what I wanted to hear; there is, I find, plenty in this Hi-Fi pursuit that can lead you at times to question your own sanity, that is in the sense of - I thought I was decisive etc :banghead:.

I will report back!

JBL 4645
11-11-2008, 01:01 PM
Tony

Even if you were to do this rather incredible simple task!

Use wideband pink noise again!

Take the outputs of the LF and HF and pass them into a graphic equalizer that has spectrum analysis display and take a look at the HF side it should be equal form side to side!

Also the two signals of left and right HF should double up on the display if they don’t when adding one of the HF channels to the other if it is the same level then one side is out-of-phase with the other.

User’s manual for JBL 5235
http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-5235%20manual.pdf (http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-5235%20manual.pdf)

Tony
11-12-2008, 01:00 PM
It would seem that I have found the problem -the internal / external crossover switch on the RH speaker. While I had done this previously I vigorously worked the switch backward and forth, reconnected and low and behold success, the soundstage is back where it should be. Thanks jblbgw man!

While I have followed the threads for 4430's where it seems the 'jury is still out' as to whether the internal crossover or bi-amping with the external crossover is preferred, I hae to say that to my ears it is a definite positive for bi-amping and external crossover (5235 with 4430/4435 networks cards). IMHO the sound is clearer with more definition and a wider and slightly taller soundstage. At this point I am well pleased although shall be looking to have the crossover swithch properly cleaned and/or bypassed as well as hopefully borrowing some measurement equipment.
Thank you to everyone for the help given.:cheers:

mvaldes
11-12-2008, 05:10 PM
It would seem that I have found the problem -the internal / external crossover switch on the RH speaker.


this is what I've suggested since my first replay....

By the way, if you have the possibility, try a different crossover than the 5235. The 5235 is not an Hi-fi product.
If you like the 4430s when biampling, you will love them with a better crossover.

Michele

jblbgw_man
11-12-2008, 09:27 PM
By the way, if you have the possibility, try a different crossover than the 5235. The 5235 is not an Hi-fi product.
If you like the 4430s when biampling, you will love them with a better crossover.

Michele
"What is a HI FI product" ?.... I have posted a simple upgrade of the 5235's in previous posts using Burr Brown chips and using high grade electrolytic caps in place of the originals. Look at my post here #8 http://www.audioheritage.org/vbulletin/showthread.php?p=223820&highlight=burr+brown#post223820 AND this one with pics http://www.audioheritage.org/vbulletin/showthread.php?t=21031&highlight=5235 This explains why you should try and retain the 5235 with the 4430/4435 cards. When looking at the graph of the voltage drives of the 4430/4435 cards you will notice the LF shelving applied ......... this is not insignificant, it is a 5dB reduction at 800Hz! If you can achieve that and the same phase response with something more bling bling then good luck! If the 4430/4435 cards produced standard 12, 18 or 24 dB filter slopes then no problems use anything that is "better" but I would be suprised if there was anything stock on the market that could duplicate the same slopes and phase response AND sounded "better" weather it be digital or analog. Don't forget the main problem with mixing consumer electronics with professional products is the huge nominal operating level difference of -10dBu for consumer and +4dBu for professional products, a whopping nominal 14dB difference! This in my view is why some people don't get the results from professional products that they think they are going to get.

Tony
11-12-2008, 09:43 PM
Thank you Mvaldes and Jblbgw man, you were both spot-on with your diagnosis. :applaud:

As to alternative crossovers to the 5235, I agree with Jblbgw man I have tried a Pioneer and DBX crossover with very disappointing results, before I managed to acquire 4430/4435 network cards. As I said before I like the result and do not find the 5235 has stamped an audio signature of any notable departure from when operating passive; just clearer presentation, with more definition and dynamics and with a slightly but definately wider and taller soundstage. As I have two 5235 crossovers I intend to experiment and intend to replicate Jblbgw man's upgrades in one, while keeping the other standard.

What alternative crossover would you suggest Mvaldes?

It would seem that the 5235 crossover has remained in active professional service for a great many years - its credentials cannot be too tarnished in this modern age.:rockon2:

jblbgw_man
11-13-2008, 02:08 AM
Tony, just for the record I did not A/B listen test with the high grade audio caps, I just replaced them as a matter of course. Here is a link to the ones I purchased from RS Components http://australia.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=4534715 . The most significant difference was replacing the 5532's with the OPA627's. I did replace the TL074's with both Burr Brown 4134 and National Semiconductors LM4562 ........... to be honest there was no improvement in sonic performance with this upgrade. Now before everybody jumps in an quotes the spec difference of these chips, what I am saying is in this configuration/topology they did not exibit an improvement, thats not to say with a better decoupled power supply, circuit layout and better input shielding or gaurding around the input leads of the chip that they might exhibit better performance. Remember the idea of this mod to the 5235 was a quick and simple mod to impliment and not a re design. Good luck with the mods I found them to be a very worthwhile simple upgrade.

mvaldes
11-13-2008, 03:40 PM
"What is a HI FI product" ?.... I have posted a simple upgrade of the 5235's in previous posts using Burr Brown chips and using high grade electrolytic caps in place of the originals. Look at my post here #8 http://www.audioheritage.org/vbulletin/showthread.php?p=223820&highlight=burr+brown#post223820 AND this one with pics http://www.audioheritage.org/vbulletin/showthread.php?t=21031&highlight=5235 This explains why you should try and retain the 5235 with the 4430/4435 cards. When looking at the graph of the voltage drives of the 4430/4435 cards you will notice the LF shelving applied ......... this is not insignificant, it is a 5dB reduction at 800Hz! If you can achieve that and the same phase response with something more bling bling then good luck! If the 4430/4435 cards produced standard 12, 18 or 24 dB filter slopes then no problems use anything that is "better" but I would be suprised if there was anything stock on the market that could duplicate the same slopes and phase response AND sounded "better" weather it be digital or analog. Don't forget the main problem with mixing consumer electronics with professional products is the huge nominal operating level difference of -10dBu for consumer and +4dBu for professional products, a whopping nominal 14dB difference! This in my view is why some people don't get the results from professional products that they think they are going to get.

Well, I’m sure that a 5235 with your tweak will sound much better than the stock ones.
But it will remain a entry level pro sound product and I wouldn’t use it in any Hi-End setup.
This is just my opinion (although there are other forumer that agree with )
The improvement you can obtain using a better sounding product are so important that you will not miss the lack of the LF shelving.

Michele

jblbgw_man
11-13-2008, 05:51 PM
The improvement you can obtain using a better sounding product are so important that you will not miss the lack of the LF shelving.

Michele
:eek:

Tony
11-13-2008, 06:38 PM
Well, I’m sure that a 5235 with your tweak will sound much better than the stock ones.
But it will remain a entry level pro sound product and I wouldn’t use it in any Hi-End setup.
This is just my opinion (although there are other forumer that agree with )
The improvement you can obtain using a better sounding product are so important that you will not miss the lack of the LF shelving.

Michele

Michele, What crossovers would you suggest?

mvaldes
11-13-2008, 08:06 PM
Michele, What crossovers would you suggest?

The only suggestion I can give you is based on my experience.
Bryston 10B or Pass XVR1. The XVR1 is the one that I've now on my system


Michele

mvaldes
11-13-2008, 08:07 PM
:eek:

Have you ever tried ?

Michele



PS: for the same reason I would never use again a 5235, I would never use again a DEQ2496.....

JBL 4645
11-13-2008, 09:22 PM
So what am I chopped liver around here? :D Glad you sorted it out in the end trial and error it would seem.

jblbgw_man
11-13-2008, 11:54 PM
Have you ever tried ?

Michele



PS: for the same reason I would never use again a 5235, I would never use again a DEQ2496.....
No ........ I have only tried BSS and DBX, I am very fond of the BSS and very not so fond of the DBX.

I can certainly notice the difference between a non 4430/4435 network and a standard 24dB LW filter network. I prefer the LF shelving in the 5235. I agree about the DEQ2496 I must of been temporarily insane when I bought mine, I certainly don't use it in my system, some claim here it makes a great RTA but I'm still not convinced of this either ...... more time needed experimenting...... would you like to buy one :D.

mvaldes
11-14-2008, 05:39 AM
No ........ I have only tried BSS and DBX, I am very fond of the BSS and very not so fond of the DBX.

I can certainly notice the difference between a non 4430/4435 network and a standard 24dB LW filter network. I prefer the LF shelving in the 5235. I agree about the DEQ2496 I must of been temporarily insane when I bought mine, I certainly don't use it in my system, some claim here it makes a great RTA but I'm still not convinced of this either ...... more time needed experimenting...... would you like to buy one :D.


well....I'm ever been curious about this LF shelving.
The LF passive crossover is just standard 12db with a zobel network, no any other special circuit in it
So, I suppose that using a good electronic crossover should be fine.....and the XVR1 is a quite good one...
Do you have any other info regarding why the 4430 card for 5235 have this LF shelving ?

Michele

Tony
11-14-2008, 11:24 AM
The only suggestion I can give you is based on my experience.
Bryston 10B or Pass XVR1. The XVR1 is the one that I've now on my system


Michele

And your using the XVR1 with 4430's?
you used the 10B previously with 4430's?

jblbgw_man
11-14-2008, 02:26 PM
well....I'm ever been curious about this LF shelving.
The LF passive crossover is just standard 12db with a zobel network, no any other special circuit in it
So, I suppose that using a good electronic crossover should be fine.....and the XVR1 is a quite good one...
Do you have any other info regarding why the 4430 card for 5235 have this LF shelving ?

Michele
I don't know ... I did'nt design the 5235 and more specifically the filter cards for the 4430/4435, JBL could have quite easily made the filter cards standard 12dB slopes with standard 12dB phase response if they wanted or thought apropriate for the 4430/4435 ... but they did'nt ....... maybe you should take this up with the JBL design engineers and explain this to them and set them straight ......... maybe it was an oversight on their behalf! :blink:

Chas
11-14-2008, 03:12 PM
Yup, ditch the switch, ASAP. I had the same problem here, although I do not run mine active, I did finally squirt some Caig deoxit in mine, when I upgraded the passive xover caps.

Check out Marchand for affordable, quality active xover solutions. Phil Marchand can likely do the CD eq for you, as well. Highly recommended.

http://www.marchandelec.com/

mvaldes
11-14-2008, 03:56 PM
And your using the XVR1 with 4430's?
you used the 10B previously with 4430's?

Yes, I'm using the XVR1 with 4430
and yes, before the XVR1 I had the 10B, and used it with 4430


Michele

mvaldes
11-14-2008, 04:09 PM
I don't know ... I did'nt design the 5235 and more specifically the filter cards for the 4430/4435, JBL could have quite easily made the filter cards standard 12dB slopes with standard 12dB phase response if they wanted or thought apropriate for the 4430/4435 ... but they did'nt ....... maybe you should take this up with the JBL design engineers and explain this to them and set them straight ......... maybe it was an oversight on their behalf! :blink:

OK.....I was just curios.
Anyway, I'm very satisfied of my setup with the PASS LABS crossover
I can't hear any problem, nor can my Clio measurement system....:)


Michele

mvaldes
11-14-2008, 04:22 PM
Yup, ditch the switch, ASAP. I had the same problem here, although I do not run mine active, I did finally squirt some Caig deoxit in mine, when I upgraded the passive xover caps.

Check out Marchand for affordable, quality active xover solutions. Phil Marchand can likely do the CD eq for you, as well. Highly recommended.

http://www.marchandelec.com/

I never had one Marchand, but I heard that they are very good crossover.
But if you keep the original passive crossover you don't need the CD eq.

Michele

jblbgw_man
11-14-2008, 04:47 PM
I can't hear any problem, nor can my Clio measurement system....:)


Michele
Thats wierd, I was always led to believe Clio was an accurate measuring tool and Im sure it is by all acounts. I would have thought Clio would have had the necessary resoloution to picked the wopping 5dB reduction at 800Hz up relativley easily, I suppose like all spectrum analaysis tools it depends on how it is set up, it stands out like dogs balls on the voltage drives .... go figure :blink: :dont-know

mvaldes
11-14-2008, 05:42 PM
Thats wierd, I was always led to believe Clio was an accurate measuring tool and Im sure it is by all acounts. I would have thought Clio would have had the necessary resoloution to picked the wopping 5dB reduction at 800Hz up relativley easily, I suppose like all spectrum analaysis tools it depends on how it is set up, it stands out like dogs balls on the voltage drives .... go figure :blink: :dont-know

believe me, I know how to use Clio.
I think you are overestimating this LF shielving...
And you are underestimating other people capability.
Choosing the right cut over frequency combined with the right Q and slope, con solve your "LF shielving nightmare".
Obviously you must know how to use a good measurement system (like Clio). And more obviously you must own it...

Now I must go....I must inform all other people that I know and that aren't using the 5235 with 4430 card that they are so incompetents....;)

Michele

jblbgw_man
11-14-2008, 06:28 PM
Check out Marchand for affordable, quality active xover solutions. Phil Marchand can likely do the CD eq for you, as well. Highly recommended.

http://www.marchandelec.com/

Sorry for butting in here and I don't mean to be critical but I thought I would check out the Marchland xovers. Looking at the schematics I am amazed that this would sound better than the 5235. It is basically the same filter op amp topology and they are only using LF353 op amps which is the same family of JFET op amps as the TLO72, except one is Texas Instruments and the other National Semiconductor. Infact if you look at the front end of the XM9 the differential input is only a single op amp, the problem with this is that you have a differing input impeadence on each + and - inputs or differing loads presented to the source, this is poor design principle and should raise alarm bells for the rest of the design, it will have an adverse effect on the CMMR if run using a balanced source, at least UREI/JBL used 2 op amps so the input impeadence on each leg is equal and using a purpose higher current low source impeadnece line drive op amp on the output to drive complicated loads that can be encountered in real life. The build quality of the XM9's is comparable with what a hobbiest would produce on his kitchen table or to the stuff I used to build when I was 14. I know this "hand made" thingy is suposed to imply some sort of superiority to some but not me. The difference here is that the 5235 is a very early 80's (or earlier) design and the Marchland is a 2000 design but the same topology and using basically the same chips :blink: ....... I don't understand how this would get the thumbs up compared to the 5235, sometimes the audio industry confuses the hec out of me :spin: and is more to do with "names" rather than engineering principles.

NOW don't get me wrong here, I am not saying the 5235 with 4430/4435 cards is the best analog cross over ever produced by mankind, what I am saying is that because of the specific filter slopes and phase response it is the most apropriate for the 4430/4435 and yes Nelson Pass AND Brystons AND BGW's crossovers with discrete op amps are a better performer, no question ! Now if either of these crossovers could produce the same filter slopes and phase response as the 4430/4435 cards then I would buy one no question .... so it depends on what you value more ... correct filter network with LF shelving and phase response making the system more balanced or a slightly "cleaner" sound .... I go for the appropriate slopes with shelving and phase response and others go for the discrete op amp thing .... no problems now lets move on ....... sorry if my views have offended anybody :cheers:

Chas
11-14-2008, 08:17 PM
I can understand your sentiments based on the info they provide on the web. However, there are "audiophile" high performance upgrades that Phil can provide. You only have to ask....In fact, I would go as far as to say that Marchand has provided me something that fits neatly (sound-wise)with my Mark Levinson No. 326S preamp, with my own bal I/O and power.

LF and TLO series chips are so far from reality, these days....

Charles.

Robh3606
11-14-2008, 08:54 PM
Op amp envy??

Rob:)

Tony
11-15-2008, 01:31 AM
This thread has produced some really useful information for bi-amping 4430's and 4435's :applaud:

mvaldes
11-15-2008, 05:09 PM
NOW don't get me wrong here, I am not saying the 5235 with 4430/4435 cards is the best analog cross over ever produced by mankind, what I am saying is that because of the specific filter slopes and phase response it is the most apropriate for the 4430/4435 and yes Nelson Pass AND Brystons AND BGW's crossovers with discrete op amps are a better performer, no question ! Now if either of these crossovers could produce the same filter slopes and phase response as the 4430/4435 cards then I would buy one no question .... so it depends on what you value more ... correct filter network with LF shelving and phase response making the system more balanced or a slightly "cleaner" sound .... I go for the appropriate slopes with shelving and phase response and others go for the discrete op amp thing .... no problems now lets move on ....... sorry if my views have offended anybody :cheers:



No one offended here….:cheers:
I’m in NY now, but next week I’ll be back home.
I still have my 5235, no…. to be honest, I have two of them. Yes, because it has been my first experience with electronic crossover and was so excited that I found a second one for cheap and bought it as a spare…..this was quite long time ago. Then I found out that the passive crossover sounded better than active with 5235 (stock one, not modded…) and start changing electronic xo until I ended with the XVR1.
I can try to run some test and compare the 4430 driven with it (the 5235) and with the XVR1.
Just for fun.

If this can help….
Michele

4313B
11-15-2008, 05:12 PM
The nice thing about the 4430/4435 is that the top end can be line level charge coupled passive and the bottom end can be the usual op-amp solution. It's best to build a charge coupled bi-amp only filter for it too and dump that switch. I detailed all this years ago.

mvaldes
11-15-2008, 05:22 PM
The nice thing about the 4430/4435 is that the top end can be line level charge coupled passive and the bottom end can be the usual op-amp solution. It's best to build a charge coupled bi-amp only filter for it too and dump that switch. I detailed all this years ago.

Right. Following what you wrote at that time, this is what I'm working on now. (little bit late, but now I've more spare time that then)
I making a new crossover, only for bi-amp, gettin rid of the bi-amp switch and Lpad's (I'm using fixed resistor).


Michele

Ian Mackenzie
11-15-2008, 07:50 PM
I think a lot of users are not aware of all the goings on in the 4430 - 4435 crossovers and with going active all those wires, switches and amps and cables it can get into a mess. Agreed a make over of the crossovers are mandatory.

What's needed is a block diagram of what happens and what goes where.

That said the 4430 was never one of my favourites and I dont think it warrants all the fussing over..they belong in discos..that 2235H cone is just too freaking heavy with that mass ring at 1 khertz. In Japan the only pair of 4430 to be seen was in the rain out the front of Dynamic Audio.
The 4435 is a totally different story.:blink:

jblbgw_man
11-15-2008, 10:04 PM
Tony .... I agree lets keep this thread going !!

4313B ..... I was initially sceptical about cc ing the 4435 network, from what I read most people agree it is worth doing so this is the next project for me, rather than re invent the wheel does anybody have any pcb's made up for the 4435 cc? ... are Solen caps the cap of choice for cc ing ?I have already replaced C7 and C9 with Clarity Caps just as an exercise and hard wired the change over switch out.

mvaldes .... This is also what I intend to do, dedicated bi amp cc network only and substituting the L Pads with fixed resistors. I would be interested in your results with the passive cc HF line level network since this is a standard slope. I would be interested in looking at the schematics for either the Bryston or Pass xovers do you have a copy of either?

Chas ..... I will give you the benefit about Marchland .... but the stuff he has on the website really is not a good example.
Cheers all :cheers:

Ian Mackenzie
11-15-2008, 10:55 PM
I was only yankin your chain.

I would not mess with a Pcb, the size of these capacitors does not lend to such.

Try bypassing the Clarity cap with a 0.01 Auricap or better still use Hovlands

Also have a look at Greg Ball's new discrete active crossover kits, full class A and Greg can execute those voltage drives.


http://www.ska-audio.com/Forum/YaBB.pl?custompage=products


Built and tested only AUD$91.00 per channel!!

An interesting idea would be a First Watt F1 or F2 (Diy) for the High Pass amp as the horn/driver can benefit from a negative impediance to smooth roughness in the 1-3 khertz range according to the designer.

4313B
11-16-2008, 08:20 AM
And just build the 6 dB high pass into the amp.

Make sure you cc that 20 uF capacitor in the 4430/4435 network though, it is the second pole of the high pass filter.

Chas
11-17-2008, 07:32 AM
The nice thing about the 4430/4435 is that the top end can be line level charge coupled passive and the bottom end can be the usual op-amp solution. It's best to build a charge coupled bi-amp only filter for it too and dump that switch. I detailed all this years ago.


A very elegant solution, for sure.:)

Tony
11-17-2008, 05:59 PM
Well my initial problem was definitely the speaker internal/crossover switch. (That is after I sorted out my initial, initial problem of getting the interconnects made up with the somewhat unusual XLR connections.) Having oscillated the switch vigorously and getting the soundstage to balance correctly, after a couple of days it began to slew to the left again - more oscillation of the switch has corrected, but I suspect only temporarily; I shall need to get someone in to take it apart and clean properly or even hard-wire.

Ian, the massive ring at 1 kHz, is that with passive crossover, or, with an active crossover not having the LF levelling that jblbgw_man refers?

4313B is there a link to crossover detail for the 4430/4435 as per your recent comment? I have searched but have not come across it, just numerous references. It would be great if all this information on the 4430/4435 could be collated. I see someone else has today opened a new thread concerning active crossovers under the DIY Forum so this subject is certainly topical.

My OPA627 opamps arrived today, so that I can commence the 5235 upgrades as per jblbgw_man :D but it will be a little while as I have other bits to gather, and I do not trust my competency to do the work myself.:o:

Ian Mackenzie
11-17-2008, 06:39 PM
The mass control ring is located within the voice coil former.

hjames
11-17-2008, 06:47 PM
4313B is there a link to crossover detail for the 4430/4435 as per your recent comment? I have searched but have not come across it, just numerous references. It would be great if all this information on the 4430/4435 could be collated. I see someone else has today opened a new thread concerning active crossovers under the DIY Forum so this subject is certainly topical.

My OAP627 opamps arrived today, so that I can commence the 5235 upgrades as per jblbgw_man :D but it will be a little while as I have other bits to gather, and I do not trust my competency to do the work myself.:o:

JBL Pro website has info on the 4430/35 at -
http://www.jblpro.com/pub/obsolete/443035.pdf

also Techbot's links ...

http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4430LR.pdf
and
http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4435LR.pdf

and these more detailed sketches ...
http://www.jblproservice.com/pdf/Network%20Schematics/3134%20Network.pdf
and
http://www.jblproservice.com/pdf/Network%20Schematics/3135%20Network.pdf


Hopefully some of this will help ...
Good luck with your project!

Tony
11-17-2008, 11:29 PM
The mass control ring is located within the voice coil former.

I guess I have shown my ignorance:o:

jblbgw_man
11-18-2008, 02:19 AM
I guess I have shown my ignorance:o:
NO you haven't at all Tony :no:, it's all a learning experience. Personally I have found the 4430/4435 the most difficult system to balance when bi amping, (and I have had 4430 since the 80's and built 2 sets) but when right it amazes me in it's performance. I believe it's a fine line between getting it right and getting it wrong, The clarity still leaves me breathless and it's totally neutral colouration (is that an oxymoron):blink:, the 2425 takes on a whole new personality when bi amped. I came from a Tannoy dual concentric background and I feel that "time alignment" is paramount .... and find the "combing effect" from multiple transducers difficult to tollerate now, others probably disagree but....... One thing for sure and that is there is a truck load of experience on here :cheers: My next upgrade will be the cc dedicated bi amp xover network for the 4435's and I hope this brings substantial benifits ... no doubt I will post my results on here :bouncy:.

Tony
11-18-2008, 03:39 PM
As often follows moments of :o: I see that I am promoted from Junior Member to Member :D

I too have found the 4430 tricky to dial-in even before bi-amping when running passive; getting the speaker position right when what seems the slightest of movements can make pronounced differences and just mico-adjustments to toe-in, in particular, having a big effect on the soundstage. Difficult manouvering the 127lb each of each 4430 - must be even worse with a 4435!

I also (seem to :screwy:) think that the system altogether gets better all on its own for a day or two when I stop fiddling with it and leave it to settle - I leave my equipment 'on' all the time.

Last night I made a big improvement; I removed the glass-topped coffee table from in front of the listening chair (I know, I know better) and that cleared things up a bit - only trouble is where to put my beer-mug;
I guess I will have to drink it!:cheers:.

Tony
11-18-2008, 03:57 PM
I’m in NY now, but next week I’ll be back home.
I still have my 5235, no…. to be honest, I have two of them. Yes, because it has been my first experience with electronic crossover and was so excited that I found a second one for cheap and bought it as a spare…..this was quite long time ago. Then I found out that the passive crossover sounded better than active with 5235 (stock one, not modded…) and start changing electronic xo until I ended with the XVR1.
I can try to run some test and compare the 4430 driven with it (the 5235) and with the XVR1.
Just for fun.

If this can help….
Michele[/quote]

Michele, This would be very interesting :cheers:

screw_squirrel
01-07-2009, 01:57 PM
Hi everybody,

I am new in this forum and i have 2 questions about how to bi-amp the 4430.
1-) I know that the dedicated crossover is the 5235 or 5234A with the correct card (1KHz, 12dB slope) but is it possible to use the JBL M552 or any other 24 dB slope crossover to do the job?
2-) i have a McIntosh 2255 amplifier right now. What other amplifier should i take if i want to bi-amp the 4430? An other MC2255? Or can i make another choice in term of brand...?
Thank you all.
Eric

4313B
01-07-2009, 02:01 PM
I posted the voltage drives years ago. If you duplicate the voltage drives you can use anything you want including building your own. The high pass is a simple 6 dB/octave circuit and you can make it either active or line level passive if you want. It works in conjunction with the 20 uF series capacitor inside the stock network to form the proper 12 dB/octave voltage drive. You have to keep that 20 uF series capacitor in there so you might as well bias it to make it sound better.

If you just slap any old 12 dB/octave 1 kHz active filter between the 2235H and the 2344A/2425H you probably won't like it. JBL put time and effort into creating the proper voltage drive for those specific components to cross over correctly at that specific frequency.

Once again, I am so angry that all the DX-1's were destroyed because they would make fantastic active networks for systems like the 4430 and 4435. The jackass(es) responsible deserve a sound beating, no pun intended.