5235 Mod

I don't know if anyone has ever tried upgrading the 5532's in this crossover but I decided I would upgrade to OPA627 on a BrownDog adaptor pcb to see what all the fuss was about. Well the improvement was outstanding:jawdrop:, clearer bottom end, much much cleaner mids and a more lively top end yet an overall smoother sound but still dynamic as all hell on my 4435's, for those of you still using this xover I can highly recommend this mod. I purchased mine from this ebay store http://stores.ebay.com.au/Parts-and-Audio but you can also get them direct from BrownDog http://cimarrontechnology.com/index.asp no affilliation. I haven't replaced the TLO74's yet as I understand they are still quite reasonable performers even by todays standards. But I will now go through my amps and bits and pieces to replace whatever they have used on the front end with these little gems, truley worth the effort IMHO. I have used 5532's for years but did'nt realise how ordinary they are.:eek: .

Yeah those BB opamps are great units.

I built a DIY active crossover based on BB 4134 opamps (instead of TL074) and the result was AMAZING.

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Originally Posted by Guido

I built a DIY active crossover based on BB 4134 opamps (instead of TL074) and the result was AMAZING.

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Thanks for that Guido, I was wondering what was a good replacement for the TLO74's without having to go to the larger 4 IC Brown Dog adaptor pcb, I would be interested, have you actually done an A/B listening test between the TL074 and the BB 4134 ?

Does anybody have a schematic for the front end of a JBL MPX300 power amp ?

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Originally Posted by jblbgw_man

I don't know if anyone has ever tried upgrading the 5532's in this crossover but I decided I would upgrade to OPA627 on a BrownDog adaptor pcb to see what all the fuss was about. Well the improvement was outstanding...

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Thanks for the info, would you be able to ellaborate a little on the replacement process, is this easy to do by someone who bsically can solder small components, but has no real electronics knowledge? If this change is so good, I'd like to do it on my XO, but I am wondering if I could tackel the job myself or be better off asking a specialist to do it for me,

Thanks and sorry if this is a very basic question, it's another opportunity to learn something from this site!

Thanks,

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Originally Posted by jblbgw_man

I would be interested, have you actually done an A/B listening test between the TL074 and the BB 4134 ?

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No A/B Test necessary. Listen to TL074, replace them and then listen to the BB's.
The 074 sounds lame and boring. Really.
Be aware that in my case listening is done via high end equipment. I have Passlabs amps and preamps!!

There are other chips around that are better and less expensive..

The best opamps are discrete opamps biased into class A as used in the Bryston and Pass labs crossovers

The BB are okay

Check out the LM4562 Buy it from digikey

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Originally Posted by scorpio

Thanks for the info, would you be able to ellaborate a little on the replacement process, is this easy to do by someone who bsically can solder small components, but has no real electronics knowledge? If this change is so good, I'd like to do it on my XO, but I am wondering if I could tackel the job myself or be better off asking a specialist to do it for me,

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Scorpio .. it is pretty basic as there are no SMD's (Surface Mount Devices) involved. Just unsolder the 5532'S with something like solderwick, being careful not to apply too much heat as to lift or damage the pads, the adaptors that I used in this instance have sockets for the DIP packages so the OPA's are "plug in" then it is just a matter of soldering in the new package, IMO only basic soldering experience is required.

Guido . I am currently in the process of tracking down the 4134 but can only find them in SOIC package so I will need a 14 pin SOIC to DIP adaptor pcb, BrownDog have these as well so I will go down this path.

Ian .. yes I was aware of the Bryston discrete opamp but was unaware of where to source them, I was going to use them on the front end of my BGW's to balance them some time ago, at the time I could'nt be bothered copying them myself :biting: and had instead copied the front end of the JBL ASC24 crossover which used OPA something a rather and instead of using discrete resistors it used a resistor matrix in the one SIL substrate package laser trimmed to 1%, I liked this idea as the topology was simpler but more importantly I also I liked the idea of the resistors being on the one substrate for temperature tracking, as you know any mismatch here results in wildly varing CMRR so I thought who ever designed the front end of this knew their stuff. I went to all the trouble of designing a pcb for this but never actualy implemented them :o: . Is someone else coppying the Bryston discrete opamp?;) ... thanks for the heads up on the LM4562, I will look into it.

The problem guys in replacing the original opamps I am finding is that sometimes there is just not enough vacant realestate on the equipment pcb to accomodate the larger upgrade as generally one package is replaced by two packages plus the adaptor pcb .......... however as the results are so impressive it is well worth the effort and to nut out a soloution, luckily the 5235 has enough room to accomodate all the chips being replaced. Now to rip open my MPX300 for the HF section and replace the nasty 5532's on the front end of that and rip open my Australian Monitor 1k2 for the LF section and replace the 5532's in the front end of that....... then maybe the BGW's next and my Aphex gear after that :banghead: Oh and one last thing ... please don't contact the ebay seller until I have purchased all that I need :D he has them at the best price ... he must have got a load in as samples or something.

:dont-know Now having said all that ...... I have used Aphex 124A's (-10dB to +4dB level interfaces) for some time and they use 5532's acording to the schematic and as far as I am concerned they are transparent in their sound .... so go figure, maybe and I say maybe that it is not the 5532'S chip that is at fault but more so the way it is implemented in the circuit, or the topology around it that effects it's performance, if you look at Aphex's topology around the 5532 it is vastly different to the way that others implement it, most topologies I have seen around the 5532 is nothing more than a kid with basic electronics and opamp knowledge would design (as in the JBL 5235). Anyway for this instance all I am interested in is sound improvment and the OPA 627'S are the way to fly and I might look into this 5532 topology a bit further when time permits.

Glad to share my experiences:applaud:and hope you all benift from the upgrade and knowledge.

I have finally started to tackle this one and got 2 pairs of BB OPA 627 and a pair of brown dog adapters, but still have two practical questions before I do something stupid...

- the adaptors I have do not have the DIP sockets, is it OK to solder the OPA directly to the adaptors, or is there a danger with that?

- alignment of the OPA's on the adaptors, my 627 do not have the little half circle indent on one of the extremities that would match the print out on the adaptor, but instead have a little round mark at one end, I guess then that this little mark is supposed to align with the print out? Sorry if this sounds like double dutch, but I don't have the macro lense that would be needed to make a picture of this....

Thanks if you can make sense out of this and provide an answer!

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Originally Posted by scorpio

I have finally started to tackle this one and got 2 pairs of BB OPA 627 and a pair of brown dog adapters, but still have two practical questions before I do something stupid...

- the adaptors I have do not have the DIP sockets, is it OK to solder the OPA directly to the adaptors, or is there a danger with that?

- alignment of the OPA's on the adaptors, my 627 do not have the little half circle indent on one of the extremities that would match the print out on the adaptor, but instead have a little round mark at one end, I guess then that this little mark is supposed to align with the print out? Sorry if this sounds like double dutch, but I don't have the macro lense that would be needed to make a picture of this....

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The only danger of soldering the OPA's directly to the adaptor pcb is 1) if you apply too much heat from the soldering iron causing the tracks to lift or damage and 2) if you apply too much solder and bridge the tracks ...... be careful.

Re alignment ....It's unusual for the OPA's not to have an indent marking but anyway don't loose any sleep over it, if it has a tiny 1mm round circle/hole adjacent to one of the end pins this usually designates pin 1 OR look at the writing on the OPA's so that it's the right way up, then the bottom left hand pin is pin 1, although this could be slightly risky if they have stamped them upside down :blink:

When soldering them onto the adaptor pcb (knowing where pin 1 is on the adaptor pcb) install the OPA's so that their pin 7 is electrically connected to pin 8 on the adaptor pcb and then to check you should find that the OPA's pin 4 is electrically connected to the adaptor pcb's pin 4 :applaud:

Good luck :bouncy:

Just further to this post I am now considering re designing the 5235 using DC coupled discrete op amps and having a matrix of sorts that will duplicate either 12 or 18 dB filter slope layouts instead of using plug in cards. I would also make the new pcb the same size so it's just a matter of removing the 5235 pcb and installing this new one ....... all because I want to keep to the original 4430/4435 voltage drives and phase response.

OK, I've done the mods today, soldering was easy, desoldering the 5532 was more of a pain, I'd bought solder wick for that job, but it did not work very well.

Anyway, maybe I would not go as far as :jawdrop: but I would certainly rate this as :D:D:D (it's all relative). Certainly for the cost and the work it is 100% worth it, much improved clarity, transparency and definition, and in my opinion improved dynamic and slam.

Now next question, should any of the condensers be upgraded as well???

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Originally Posted by scorpio

Now next question, should any of the condensers be upgraded as well???

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Yes yes yes ... audio grade electrolytics is what I used, I did the whole thing together, BB chips and caps at the same time, so I can't comment on the cap only improvment but it should be worthwhile ..... glad you are happy with the improvment so far :bouncy: .... what monitors are you using? Did you also replace the TL074's?

No I've not changed the TL074 (yet?), I will be looking into that at the same time as the caps to order everything in one go. What is the time limiting factor in this is having the time to remove the filter from the overall system as I'm using the strip connectors, not the XLR's, so I have to remove the cabling to the various amps, a royal pain.

I'm using a system based on 2235, 2450 and 2405, with a cc network between the 2450 and 2405 that is based on the 3106, it's the system you can see in my avatar.

I'm sticking to this crossover for now as I'd like to experiment with 2380 type horns at some time, and i have the necessary cards for doing so.

BB 4134

I build an active crossover using this chip about 10 years ago

That chip is actually quite coloured compared to say the OP 275

But any mass produced chip on a die is not going to perform as well as a discrete mininalist buffer. I found such chips lacked true resolving power and dynamics.

This is why most active crossovers degrade audiophile performance.

You might gain a bit of bass damping on systems like the 4344 but it otherwise downgrades the signal from the program source using hi end components

The thing is with most garden variety power amps this loss of quality introduced by an active crossover may not be particularly noticeable.

Its a case of using like with like quality

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Originally Posted by Ian Mackenzie

The thing is with most garden variety power amps this loss of quality introduced by an active crossover may not be particularly noticeable.

Its a case of using like with like quality

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:blink: Ok I get it now ..... I should be using Radio Shack speakers with my gear .... now I know where I have gone wrong :blink: thanks for the tip.

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Originally Posted by Ian Mackenzie

BB 4134

I build an active crossover using this chip about 10 years ago

That chip is actually quite coloured compared to say the OP 275

But any mass produced chip on a die is not going to perform as well as a discrete mininalist buffer. I found such chips lacked true resolving power and dynamics.

This is why most active crossovers degrade audiophile performance.

You might gain a bit of bass damping on systems like the 4344 but it otherwise downgrades the signal from the program source using hi end components

The thing is with most garden variety power amps this loss of quality introduced by an active crossover may not be particularly noticeable.

Its a case of using like with like quality

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Well, it still sounds rather good to me. I'll keep my garden variety amp with this inferior crossover rather than go back to the same amp with the passive network, as someone else rightfully says over here 'it'a all relative'.

PS; and I'm starting to get itchy of your recent bout of aggressive/negative comments towards the 'less knowledgeable' when I used to really enjoyed your contributions in the past. Some of us have limited budget and are still on the learning curve to make the best out of what they have, and eager to do so. These remarks wont help. That's it, i emptied my comment bag and won't post no more on this subject, I don't want the thread to derail into an argument.

Mods - feel free to erase if not appropriate,

Cheers,

With its absence of multiple gain and other signal degrading controls, the simplicity of the 5235 should not be maligned. I have 4430 speakers powered through a 5235 by 2 x Naim 130 amplifiers (recently upgraded by Avondale Audio UK to their stage 4) for the LF and 1 x Naim 160 for the HF.

The 5235 has been upgraded ‘a la jblbgw man’ with OPA627 opamps and Phillips caps. I am delighted with the results over the standard 5235 and believe I am now getting some of the 3D effects to the soundstage that I had previously only heard the 4430 was capable of. Of course the Remy Martin helps! Very many thanks to jblbgw man.:applaud:

While my system with Linn LP12, moderately upgraded, DVD transport and custom-built tube DAC, is not in the upper reaches if Hifi it is certainly not Lofi.:D

The biggest problem I have currently is with the external / internal crossover switch on the 4430’s and the lack of technical knowledge and/or confidence to dismantle the speakers to get at the internal crossover to clean. (At this time I would like to upgrade the internal crossover and charge-couple as has been recommended previously on this forum). This has to be my next task to have this fixed after which I would like to introduce more tubes perhaps by way of a buffer, or even tube external crossover, and/or tube amp for HF.

One of the best and cost-effective upgrades I have found for any system is to install a dedicated mains supply, preferably with a separate supply for source equipment and another for power amplifiers. IMHO this should be the first upgrade for any system.

Interesting mix Tony, Naim's are not very often seen used with JBL, my only experince of them is in full Naim systems or mixed with Linn.

I don't know how far you'd like to get with upgrading your passive filter, but I played with a standard topology 3106 crossover between my mid and tweeter, then changed it to CC and the difference is not subtle, it is also a clear improvement. Sometimes I really wished I had started with two identical systems and kept one unmodified, just to be able to assess the cumulative impact of all the improvements, you tend to get used more easily to improvements than to worsening!

If you take your time, read what is on here, ask questions when needed, you cannot go really wrong, there is a lot to reap.

One more thing, I just bought a new high quality multiple mains outlet, and I'm currently shopping for mains cable to connect those direct to the utility unit - so it seems I'm on sync with your proposed first upgrade! It will take a few weeks to complete though.

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Originally Posted by scorpio

Well, it still sounds rather good to me. I'll keep my garden variety amp with this inferior crossover rather than go back to the same amp with the passive network, as someone else rightfully says over here 'it'a all relative'.

PS; and I'm starting to get itchy of your recent bout of aggressive/negative comments towards the 'less knowledgeable' when I used to really enjoyed your contributions in the past. Some of us have limited budget and are still on the learning curve to make the best out of what they have, and eager to do so. These remarks wont help. That's it, i emptied my comment bag and won't post no more on this subject, I don't want the thread to derail into an argument.

Mods - feel free to erase if not appropriate,

Cheers,

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Knowledge : I suggest you use the search engine

I have covered all this ground in numerous threads with other members and there is nothing negative about it when taken in context of such.

The point is your improvements are valid but must be taken in consideration of a much large picture.

For exampe we found that an upgraded 4343 to a 4344 sounded better overall run directly from a Passlabs X 150 (or a X250 I dont recall the specifics) than via an active crossover. It took some convincing to ask the particular member to try this but when he did he stayed up all night.

A full discrete class A active crossover was later built and it was regarded as close to nirvana by the user. Other people have used the Bryston active crossovers with similar experiences.

I would point out I have never paid (a lot) for the hi end stuff I posses and have built most of it.


Have a look at this http://www.ska-audio.com/Forum/YaBB....mpage=products

I have ordered the active crossover kit to build and try out.

High quality need not be expensive


As to tweaking and upgrading its a bit like the ultimate cd player thread with people upgrading play stations and as you would expect the guy who does his own upgrades is always going to claim they make a big difference. Then a guy with a $5000 player enters the discussion and says maybe but this a better.

Both have every right to feel the wow factor just dont expect everyone to share your expectations. One guy spent a year replacing every chip and capacitor in his Westlake crossovers and remarked about the improvement. He then finally did something completely different and proclaimed it was better again and so it goes on.

I spent a long time tweaking chip based gear, preamps, crossovers and other stuff and I know its fun.

But then I discovered hghly biased class A designs. There simply is no comparison.

:blink: Gentlemen ….. I only ever started this thread as an inexpensive, easy, quick upgrade to the 5235 which does provide substantial sonic improvement to the 5235. I have never held the mod out to be the be all and end all of mods …. Just quick and easy, but since the inception I have been bagged.

When judging JBL crossovers don’t ever get the 5234 and the 5235 confused, they are totally different beasts, different topologies and different chips. I have posted elsewhere where I find it mind boggling that people will slam the 5235 but praise other makes of crossovers, but when you analyse the schematics of the other cross over’s the topologies are either identical or technically inferior and these are current designs, where as the 5235 is an early 80’s design …. But again they slam the 5235 but praise the others …. Go figure !!:banghead:

This is a JBL forum, I use it for discussing JBL products and DIY improvements, and it’s fast becoming an elitist stomping ground for Nelson Pass and 4345 devotee’s …… To be honest I’m getting sick of hearing Nelson Pass’s name on this JBL site ……. If you guys want to sing the praises of Nelson Pass and his gear I suggest you keep it for the DIYAudio forum or start up your own Pass Labs Forum where you can mix with like minded devotees.:D

Not unlike some on here I am time poor, but …. I certainly do not lack the technical expertise or knowledge to carry out these mods and redesign stuff, it’s just when you do it for a living it sort of wears thin after a while and other things take priority in life…… like life itself.

I happen to like BGW stuff, always have and always will but I don’t go around bagging other peoples stuff and singing the praises of BGW and taking cheap shots, I don’t have the defect in my character to need to feel superior to anybody, unlike some Nelson Pass devotee’s who do this at every opportunity to mention that they set the standard on this site.

As mentioned before with the 4430/4435 I happen to think it is important to keep the same filter characteristics (i.e. same voltage and same phase response as the 52-5130 network cards) as what the system designer intended as I don’t profess to know more than the JBL design engineers. I have tried the 4435’s with standard LR 24/12dB slopes but always end up going back to the 5235 with correct filter slopes as this sounds more natural. I am looking at redesigning the 5235 pcb using discrete class A op amps but retaining the 4430/4435 filter characteristics, keeping the pcb the same size as the 5235 so it can easily be retrofitted into the 5235 chassis but by the sounds of it, this wouldn’t be good enough for some of you because it won’t have Pass Labs or Bryston stamped on the chassis.:banghead:

Unlike some I don’t have endless amounts of money to pour into a self indulging hobby anymore so I make the most of what I have and I am happy with what I have, as humble as a system it might be to the elitists but I am happy, now who else can honestly say that.

Now moderators …. If you wish to pull my post again then that’s fine I have no problem with that but if you do it this time then take one step further and delete my membership and all my posts as well please.

To the few of you that have done the upgrade I am happy that I could in such a small way help you to attain an improvement in your systems, this satisfies me immensely.:D

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Originally Posted by scorpio

One more thing, I just bought a new high quality multiple mains outlet, and I'm currently shopping for mains cable to connect those direct to the utility unit - so it seems I'm on sync with your proposed first upgrade! It will take a few weeks to complete though.

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I reckon you will be very pleasantly surprised by the result which will improve further as your new cable burns-in. I used 10.2 guage cable.

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Originally Posted by Tony

One of the best and cost-effective upgrades I have found for any system is to install a dedicated mains supply, preferably with a separate supply for source equipment and another for power amplifiers. IMHO this should be the first upgrade for any system.

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Tony I did a similar thing when I re vamped my lounge room, I had a seperate dedicated mains supply to each speaker/amp and Control rack and had them "star" wired back to the sub board, it certainly cleaned up any earthing issues.

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Originally Posted by jblbgw_man

:blink: Gentlemen ….. I only ever started this thread as an inexpensive, easy, quick upgrade to the 5235 which does provide substantial sonic improvement to the 5235. I have never held the mod out to be the be all and end all of mods …. Just quick and easy, but since the inception I have been bagged.

When judging JBL crossovers don’t ever get the 5234 and the 5235 confused, they are totally different beasts, different topologies and different chips. I have posted elsewhere where I find it mind boggling that people will slam the 5235 but praise other makes of crossovers, but when you analyse the schematics of the other cross over’s the topologies are either identical or technically inferior and these are current designs, where as the 5235 is an early 80’s design …. But again they slam the 5235 but praise the others …. Go figure !!:banghead:

This is a JBL forum, I use it for discussing JBL products and DIY improvements, and it’s fast becoming an elitist stomping ground for Nelson Pass and 4345 devotee’s …… To be honest I’m getting sick of hearing Nelson Pass’s name on this JBL site ……. If you guys want to sing the praises of Nelson Pass and his gear I suggest you keep it for the DIYAudio forum or start up your own Pass Labs Forum where you can mix with like minded devotees.:D

Not unlike some on here I am time poor, but …. I certainly do not lack the technical expertise or knowledge to carry out these mods and redesign stuff, it’s just when you do it for a living it sort of wears thin after a while and other things take priority in life…… like life itself.

I happen to like BGW stuff, always have and always will but I don’t go around bagging other peoples stuff and singing the praises of BGW and taking cheap shots, I don’t have the defect in my character to need to feel superior to anybody, unlike some Nelson Pass devotee’s who do this at every opportunity to mention that they set the standard on this site.

As mentioned before with the 4430/4435 I happen to think it is important to keep the same filter characteristics (i.e. same voltage and same phase response as the 52-5130 network cards) as what the system designer intended as I don’t profess to know more than the JBL design engineers. I have tried the 4435’s with standard LR 24/12dB slopes but always end up going back to the 5235 with correct filter slopes as this sounds more natural. I am looking at redesigning the 5235 pcb using discrete class A op amps but retaining the 4430/4435 filter characteristics, keeping the pcb the same size as the 5235 so it can easily be retrofitted into the 5235 chassis but by the sounds of it, this wouldn’t be good enough for some of you because it won’t have Pass Labs or Bryston stamped on the chassis.:banghead:

Unlike some I don’t have endless amounts of money to pour into a self indulging hobby anymore so I make the most of what I have and I am happy with what I have, as humble as a system it might be to the elitists but I am happy, now who else can honestly say that.

Now moderators …. If you wish to pull my post again then that’s fine I have no problem with that but if you do it this time then take one step further and delete my membership and all my posts as well please.

To the few of you that have done the upgrade I am happy that I could in such a small way help you to attain an improvement in your systems, this satisfies me immensely.:D

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There is nothing superior or elitist about any of this .......Na..na

I worked it out that the cost of the 627 chips and the adapter pcs would outweight the cost of a new diy project.

If you want to be a die hard upgrader go for it.

Its just like a lot of hard work for the end result.

I recall Giskard posted all the upgrades for the 5235, even CC the capacitors.

The BGW were great amps by the way!!

Quote:

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Originally Posted by jblbgw_man

:blink: Gentlemen ….. I only ever started this thread as an inexpensive, easy, quick upgrade to the 5235 which does provide substantial sonic improvement to the 5235. I have never held the mod out to be the be all and end all of mods …. Just quick and easy, but since the inception I have been bagged.



This is a JBL forum, I use it for discussing JBL products and DIY improvements, and it’s fast becoming an elitist stomping ground ...

... it’s just when you do it for a living it sort of wears thin after a while and other things take priority in life…… like life itself.

Unlike some I don’t have endless amounts of money to pour into a self indulging hobby anymore so I make the most of what I have and I am happy with what I have, as humble as a system it might be to the elitists but I am happy, now who else can honestly say that.
.:D

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I for one say thanks so much for sharing!
Fun as it is, rewarding as it is, this is a hobby and other things in life do call up the lions share of the funds!

Buy carefully and appreciate what you've got is a good motto!
Have a great weekend!

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Originally Posted by Ian Mackenzie

There is nothing superior or elitist about any of this .......Na..na

Whatever

I worked it out that the cost of the 627 chips and the adapter pcs would outweight the cost of a new diy project.

Your maths IS floored, show your workings out and include your time for a new DIY design including R&D and pcb design time. Do it long hand fashion then you will easily pick the error of your workings out. I presume your fingers are to big to use a calculator :D.

If you want to be a die hard upgrader go for it.

What 1 upgrade and now I am a die hard ...... and whats wrong with being an upgrader, isn't that what most people on this site are doing?:blink:

Its just like a lot of hard work for the end result.

What replacing a couple of chips and a few caps ... how hard can that be? ...... f*&k you must be lazy. :banghead:

I recall Giskard posted all the upgrades for the 5235, even CC the capacitors.

I'm not aware of this, he obviously did'nt create a storm like I did, I suppose you have to "earn" your stripes on LHF, I somehow doubt I will be around long enough for this to happen.

The BGW were great amps by the way!!
No need to convince me, thanks for your stamp of aproval BTW, I will sleep better knowing this.

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And JBL put their name to this forum :biting:
OK OUT !!! :blink: :D

[quote=scorpio;239492]Interesting mix Tony, Naim's are not very often seen used with JBL, my only experince of them is in full Naim systems or mixed with Linn.

I have used Naim amplification since the late 80's and only with JBL speakers - L19, Century Gold and now 4430's. I guess I like the JBL sound :).

http://www.soundlabsgroup.com.au/c/ICs/ICs.html

$50 for the chip. You mighe be able to source for less but unlikley for single units

http://www.soundlabsgroup.com.au/c/I...+Adapters.html

say $10 for the adapter

= $60.00

I might be stupid but I am not that stupid

As for my design? , its a class discrete design of common topology and there are numerous variations

I use a dual Jfet $7.00 each, a few transisters and resisters and a 2.5 cn square pcb ...say $12.00 all up for a discrete opamp

You can good up the RC values on vero board or as I do make a printed pcb..its not that hard to do so.

On replacing parts on a existing board unless you have the right tools its not to be encouraged..burnt and lifted pcb tracks are not particularly reliable.

You need to be mindful of the rules, name calling and F words are not allowed:blah:. There are numerous people on the forums usig Pass equipment:).

In case you are not aware, most chip opamps and only bias with faction of a mA, a discrete opamp can up 7-10 mA of bias and therefore will always work in class A. The PS in the 5235 is unlikely to handle that current of say a dozen opamps collectively.

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Originally Posted by Ian Mackenzie

http://www.soundlabsgroup.com.au/c/ICs/ICs.html

$50 for the chip. You mighe be able to source for less but unlikley for single units

http://www.soundlabsgroup.com.au/c/I...+Adapters.html

say $10 for the adapter

= $60.00

I paid a lot less than that from an ebay store :D Soundlabs are too expensive.

I might be stupid but I am not that stupid

You have inadvertantly not included your time into your equation, initial time to R&D and time to design and manfacture/build/populate a pcb. :scold: unless of course you ripped the design out of a magazine along with the pcb, then you must include the cost of the magazine :D.

As for my design? , its a class discrete design of common topology and there are numerous variations

I use a dual Jfet $7.00 each, a few transisters and resisters and a 2.5 cn square pcb ...say $12.00 all up for a discrete opamp

I use transistors and resistors, I'm not familiar with transisters and resisters .... are they something new? ;) ..... now does your thing have the same open loop gain characteristics as an OPA627, is it as stable as an OPA627, can it drive a load like an OPA627, what is it's Common Mode performance like please, what's its slew rate and do you have a noise figure for it.

You can good up the RC values on vero board or as I do make a printed pcb..its not that hard to do so.

On replacing parts on a existing board unless you have the right tools its not to be encouraged..burnt and lifted pcb tracks are not particularly reliable.

So who burnt their tracks and lifted their tracks :dont-know..... Now are you discouraging any type of modification here, to anything ..... by anybody on a DIY forum :rotfl: .... unless sanctiond by yourself, I have only been doing this for let me see .... um .... 38 years and 34 of them professionally ...... like for a living you know, ...... I may have not reached your standard of vero board but please forgive me if I design a pcb for everything I do.

You need to be mindful of the rules, name calling and F words are not allowed:blah:.

Yes .... maybe I should have not called you lazy, as you keep replying to my posts you can't be quite that lazy.

There are numerous people on the forums usig Pass equipment:).

And there are probably more people not using Pass equipment than people that are.

In case you are not aware, most chip opamps and only bias with faction of a mA, a discrete opamp can up 7-10 mA of bias and therefore will always work in class A. The PS in the 5235 is unlikely to handle that current of say a dozen opamps collectively.

I think what you mean is chip amps input bias current might be in the order of pico Amps but don't forget their total supply current is in the order of typically 15 milli Amps or so, so without doing the math I still reckon the 5235 ps will handle it .... but hey ... if not, I gues I could increase the size of the transformer to cover it .... mod number 2 !!! :applaud:

---

:banghead: Why are people so negative around here is it because they didn't post the upgrade ? they didn't come up with the idea? or they don't like other people comming into their territory.

http://www.soundlabsgroup.com.au/c/ICs/ICs.html

$50 for the chip. You mighe be able to source for less but unlikley for single units

http://www.soundlabsgroup.com.au/c/I...+Adapters.html

say $10 for the adapter

= $60.00

Hmm, I got 4 * 627 for 25 euros on e-bay, incl shipping, and the pair of browndog was $8.5 shipping included directly from the US.... Had I waited another week, I could have bought 2 pairs of browndogs with the 627 installed for 30 euros shipped. patience, patience....

jblbgw_man & scorpio,

For the record your posts are becoming more negative as the day rolls on.

You took my earlier post on the 4134 as an excuse to try start a bitch session on your own terms. Fail.

The whole topic is rather tired and reads like the guide to better mouse trap when its been beaten and hacked to death.

I am merely pointing out alternatives that other readers may find attractive (and have found highly successful).

That is within the rules.

You have seen fit to break the rules in terms of your behaviours and I suspect you will keep doing that because you enjoy it.

Decide if you want to stay or leave. That is your call.

Its only Feb 2009.

Of a more pragmatic and rational nature the average member would not have the skills to implement the mods to the 5235 you have described and I therefore question the value of it being in this particular forum or even being posted unless you are prepared offer an upgrade serviceor an instructional documented guide.

What you are doing is in principle a "personal" diy modification and while I can appreciate you might want to post or blog the story you should expect & anticpate comments, debate and discussions on what you are doing.

That is withn the Rules.

If you cant deal with that you don't belong on any public forums.

If you want to be a smart ass think twice about it.

I had no problem ripping though John Curl on Diy audio who relented.

My earlier point was that based on vast experience of a group of people (for those with a wider enough perspective on reality) that all these chip updates are just improvements to some ears and not others who might say its sounds different but not better.

Then there are things like power supplies and parts selection which can be a bigger mine field and it becomes inevitable that you end up with not a modification but a new bit of gear.

If you are prepared to look beyond that you can do a whole lot better if you are smart. The auditory problem is that when you mix and match different audio equipment in different systems the sonic differences are sometimes there and sometimes not. Hence I would caution anyone considering ripping into their 5235 to think about it (before you wipe of its Ebay value)

Its been picked over here on the forum on many ocassions. It would be useful to have all these types of threads on one place and figure outwhose thread was worth reading. Personally I would only bother reading 4313B's posts on the 5235 mods.

I would recommend the Ashy cossovers as a good alternative to the JBL 5235. Beyond that there are items like the Bryston which is a huge jump on the stock JBL crossovers , the Passlabs XVR1, the DEQX or some of the class A diy kits like Greg Ball, Borbely Audio and a few others in Europe supply.

In a commercial realisation JBL produced the DX1 but unfortunately the stock that was reserved for members was destroyed. The DX1 was designed for the real HiFi audio and had many unique features for a commercial crossover such as discrete class A high pass filter buffers, charge coupled filter capacitors and programmable filters among others.

Those that own them rave about them.

I have used two DX1 and used them extensively for some time along side the stock 5235. The difference is not subtle.

I am not going to comment on the specifics of the discrete opamp I am using as there are 100's of pages on diyaudio covering that topic including measurements. The circuit is identical for all intensive purposes to the XVR1 and there are specs on that unit. The proof is in the listening.

Quote:

---

Originally Posted by Ian Mackenzie

jblbgw_man & scorpio,

For the record your posts are becoming more negative as the day rolls on.

You took my earlier post on the 4134 as an excuse to try start a bitch session on your own terms. Fail.

The whole topic is rather tired and reads like the guide to better mouse trap when its been beaten and hacked to death.

I am merely pointing out alternatives that other readers may find attractive (and have found highly successful).

That is within the rules.

You have seen fit to break the rules in terms of your behaviours and I suspect you will keep doing that because you enjoy it.

Decide if you want to stay or leave. That is your call.

Its only Feb 2009.

Of a more pragmatic and rational nature the average member would not have the skills to implement the mods to the 5235 you have described and I therefore question the value of it being in this particular forum or even being posted unless you are prepared offer an upgrade serviceor an instructional documented guide.

What you are doing is in principle a "personal" diy modification and while I can appreciate you might want to post or blog the story you should expect & anticpate comments, debate and discussions on what you are doing.

That is withn the Rules.

If you cant deal with that you don't belong on any public forums.

If you want to be a smart ass think twice about it.

I had no problem ripping though John Curl on Diy audio who relented.

My earlier point was that based on vast experience of a group of people (for those with a wider enough perspective on reality) that all these chip updates are just improvements to some ears and not others who might say its sounds different but not better.

Then there are things like power supplies and parts selection which can be a bigger mine field and it becomes inevitable that you end up with not a modification but a new bit of gear.

If you are prepared to look beyond that you can do a whole lot better if you are smart. The auditory problem is that when you mix and match different audio equipment in different systems the sonic differences are sometimes there and sometimes not. Hence I would caution anyone considering ripping into their 5235 to think about it (before you wipe of its Ebay value)

Its been picked over here on the forum on many ocassions. It would be useful to have all these types of threads on one place and figure outwhose thread was worth reading. Personally I would only bother reading 4313B's posts on the 5235 mods.

I would recommend the Ashy cossovers as a good alternative to the JBL 5235. Beyond that there are items like the Bryston which is a huge jump on the stock JBL crossovers , the Passlabs XVR1, the DEQX or some of the class A diy kits like Greg Ball, Borbely Audio and a few others in Europe supply.

In a commercial realisation JBL produced the DX1 but unfortunately the stock that was reserved for members was destroyed. The DX1 was designed for the real HiFi audio and had many unique features for a commercial crossover such as discrete class A high pass filter buffers, charge coupled filter capacitors and programmable filters among others.

Those that own them rave about them.

I have used two DX1 and used them extensively for some time along side the stock 5235. The difference is not subtle.

I am not going to comment on the specifics of the discrete opamp I am using as there are 100's of pages on diyaudio covering that topic including measurements. The circuit is identical for all intensive purposes to the XVR1 and there are specs on that unit. The proof is in the listening.

---

It's about time you rested your ego Ian or at the very least controlled it, your ego is pungently and gratuitously saturated through most of your posts, others see it as well, now in the interest of keeping the forum civil ..... nuff said !! ...... or if you want to continue to discredit yourself then please continue, but you will need to find another sparring partner ... remember I have a life !! But don't let it go to your head and consider it a win !! somebody here has to be the adult !!

[quote=Ian Mackenzie;239610]jblbgw_man & scorpio,

Of a more pragmatic and rational nature the average member would not have the skills to implement the mods to the 5235 you have described and I therefore question the value of it being in this particular forum or even being posted unless you are prepared offer an upgrade service or an instructional documented guide.]

Again - I can only thank all of those who have contributed concerning modifying the 5235. I personally do not have the skills to implement, but, fortunately I know a man who has, and who has done so very satisfactorily for my 5235. I have a modified 5235 ‘a la jblbgw man’ with the OPA627 opamp and Phillips caps and a standard 5235; I have swopped the network cards between the two and, in my admittedly subjective opinion, the modifications bring forth an impressive step forward. I have not changed the TL074's as yet - I have some 4134's (awaiting adaptor) and was going to try these until Ian's recent comment.

I have found this thread and related threads concerning the 5235 and its use with 4430/4435's very useful and I, for one, hope that discussion continues and remains constructive :applaud:.

I hope so and that is why this ret#$% is on the ignore list.

As I said earlier the tweaks are certainly fun but I was so pleased with the way the 5235 was made I decided to leave it alone.

My recollection subjectively is the 5534 series chips have a lot drive but can become fatiguing and lack true resolving power and sounded too metalic with JBL's. The budget 2134-4134 are pleasing but are really very mellow and I imagine they would sound okay with the 4435, the TL072 are somewhere in between.

The TL074-72 are really not that bad but if it were me I would try some others like the BB 2604. Here are a few ideas. The BB 627 are serious money in anyone's book.

I know Huge Dean like the BB 2604.

You really want something with the drive of the 5534 but smoother and low input offset. You can also bias these chips very gently into class A with a pull down resister from the output to the negative rail ans they will clean up their act. That would help the 5534.

http://www.geocities.com/jonrisch/catch-1.htm

http://www.gearslutz.com/board/geeks...mendation.html


Benchmark Audio still use the 5534 in their stuff but I know they pay careful attention to the closed loop gain curve. I am not fond the the diodes on the input.

As mentioned in the above links some of these chips have such high open loop bandwidth and gain they are difficult to operate with reliable stability unless you pay a lot of attention to board layout, PS and compensation. For the same reasons they are very sensitive to power supply output impediance and local decoupling. You just cant plug and play with opamps if you want the best out of them.

I was given some 627s to play with but the price made discrete opamps a no brainer given you can optimise the specs like open loop gain to suit the application.

With SK filters you are really looking for low output impediance and very hi input impediance buffers to ensure the filter functions correctly. Where the buffer is operated in unity gain zillions of db open loop gain is a waste and can lead to stability issues. Circuits with massive feedback tend to sound processed and scrubbed. Therefore a simple source cathod follower can be used as a buffer for the RC networks and setup to self bias if you use 2 x Jfets.

Some useful references :

http://www.borbelyaudio.com/adobe/xover.pdf

http://www.borbelyaudio.com/adobe/ae599bor.pdf

http://www.borbelyaudio.com/adobe/ae699bor.pdf

http://www.diyaudio.com/forums/showt...=&pagenumber=1

http://www.bursonaudio.com/burson_hdam_module.htm

jblbgw_man


Hey you! Yes you.

How about hotting up an Ashly crossover for the Yanks?

Christ, if I was paid 10 bucks for every capital idea I came up with I'd be rolling in it.

Hang on I am.(:D)

Quote:

---

Originally Posted by Ian Mackenzie

How about hotting up an Ashly crossover for the Yanks?

---

Do you think the Ashly is inherently a better design? Stock, the Ashly is probably the better unit, but if both use the same upgraded opamps? Of course the Ashly is currently available which makes getting them slightly easier.


Widget

In terms of functionality I think it is.

Depending on the rest of your stuff it is as good as it need to be.

There are a lot of chip stages in the Ashly! The stuff is fit for the purpose and at least for the stock JBL vintage stuff its quite acceptable

But like start shaving the performance like Bo did and all these analogue pro crossovers (and equalisers) are questionable.

It can be a painful and expensive cycle that results in an even shorter play list. In other worfds unless you are prepared to review the entire signal chain its not something to get too excited about.

At some stage when I get everything else out of the way which will be a fair while I am going to talk to Greg Ball about something that might prove useful. He is an engineer that has worked for ML and Usher on their hi end stuff and has now turned his hand to hi performance modules.

I'm hopeful that the flames have died down just a bit on this thread.?.

Just wanted to pass along my appreciation to everyone here for the great suggestions. I never really knew what the slopes looked like on the 5235 with the 4430/35 cards. I just knew the 4430's sounded great with the 5235. It would take a lot of work do duplicate that in a passive. Many thanks to jblbgw man for that one!

I used my 4430's for many years with the passive internal crossovers. When I bought the 5235 (new) back in the late 80's, it was a revealation. I never knew these speakers could sound this great. I had actually been contemplating replacing them...till I heard them bi-amped with the proper crossover, and (of course) the proper cards for these speakers. The improvement is not subtle.

I'd just recommend that anyone with 4430 or 4435's try to secure a 5235, with the proper cards. The improvement is truly stunning.

I'm now going to do some chip and cap upgrades to mine...which still seem to sound as it did when new, but I know there are newer, and better sounding op-amps and caps these days.

Thanks again to all!
DaveObieOne

Well it certainly seems the bitching has killed the continuance of usefulness of this thread:(

Quote:

---

Originally Posted by Tony

Well it certainly seems the bitching has killed the continuance of usefulness of this thread:(

---

Yes sadly you are right, however if you need any more assistance regarding the 5235 please don't hesitate in PM me. :cheers:

Quote:

---

Originally Posted by daveobieone

I'm hopeful that the flames have died down just a bit on this thread.?.

..........................

I'm now going to do some chip and cap upgrades to mine...which still seem to sound as it did when new, but I know there are newer, and better sounding op-amps and caps these days.

Thanks again to all!
DaveObieOne

---

Have you done the upgrade?
What do you think:rockon2:

Quote:

---

Originally Posted by jblbgw_man

Yes sadly you are right, however if you need any more assistance regarding the 5235 please don't hesitate in PM me. :cheers:

---

Or me to that matter,

Hi,

I have a chance to buy a JBL 5235 for use with my 4343 speakers. However, the 5235 does not have the JBL card for my speakers and from what I see on the forum they seem to be hard to come by.
So, assuming that I cannot buy a pair of JBL 52-5140 cards, what kind of trouble am I letting myself in for? Can a populated card be (easily) rebuilt for the specifics of the 4343 speakers?

The cards with the unit appear to crossover at 150Hz... according to the label just visible in the picture on eBay.

I am also interested in upgrading the 5235.. I kind of liek bringing a unit of the same generation as my speakers back to life and then improving on it. Can anyone point me to the best source of upgrade information on the 5235?

Thanks for the help

Guido on this forum can normally have cards made for you for this application... contact him by pm would be my advice...

Quote:

---

Originally Posted by scorpio

Guido on this forum can normally have cards made for you for this application... contact him by pm would be my advice...

---

Hi,

Thanks for the advice. Guido , sadly, is out of cards, but I think that I have enough information now to build my own.... assuming no major snafus.
It has been a bit of a rabbit-chase.. the information needed is widely scattered over various forums.. but it seems to be complete. The next step is to see if I can get close tolerance components. After that, what could possibly go wrong?

Thanks to all
:)
george

[QUOTE=georgebrooke;330718]Hi,

After that, what could possibly go wrong?

Let me build it ...... LMFAO !