capacitor replacement help

[TomB19]

But yes, please, go ahead and draw up the network as you would do it, but if possible make it as easy for me to read as possible

I can see that my comments misrepresent my intention. I cannot draw a complete diagram and give it to you. What's more, I couldn't if I wanted to. There isn't enough information here.

What I can do is draw the parts of the schematic I can see and compare that to your diagram as confirmation of some/most of the diagram you have drawn.

Why not change the small value caps with your favourite brand and leave it at that? (although, as I understand it, you haven't tested across brands and lines to determine your preference so that is another head scratcher) It seems like you want to break up a lifeboat for wood to build a raft so you can float off the island.

Again, I'm not here to bully anybody but I highly doubt you are going to experience an improvement by throwing out a network filter designed by a professional speaker designer with your own. That holds true, even if the professional designer is building to a price with affordable components. As proof, I give you the discipline of engineering.

Improvements come from small, controlled, changes to an existing design. What's more, they need to be easily backed out so you can A/B your speakers (one modified, one not) and go with whichever you prefer.

As for "phase shift", that isn't really a thing at audio frequencies, as far as I am aware. You do have to be aware of saturation, however, which can cause hysteresis and distortion.

Also, those coils are not randomly placed on that board. They are positioned on three different axis so the magnetic flux from one has the least influence on the nearest other coil. That's why the two parallel coils are the furthest apart from each other. I refer you to the work of Michael Faraday.

Have you considered how much audio grade hammered steel or foil wound inductors are going to cost? Do you have a costed bill of materials?

I've seen some pretty solid deals on used B&W Diamond 804 speakers. I know it isn't about value for you but surely there is some consideration?

The easiest way to measure series resistance is to get a meter with ESR capability. ESR will also affect your crossover performance so I suggest finding caps that have similar ESR to the original ESR of the factory caps. That can be difficult, since you will probably end up putting in caps with massively higher voltage.

 

[TomB19]

yay or nay?

Maybe. It mostly looks OK but you have literally drawn four inputs without polarity or further information so I cannot know.

 

[TomB19]

ukspawn, have you ever watched reality TV shows like Overhaulin'?

You know, they take someone's ratty, trashy, car and turn it into a show car in a week? They tow a car in and then drive it out in perfect condition.

I know a few people who work at the studios where several of these reality TV shows are recorded.

Let me spoil it for you. Every one of those shows is fiction.

Oh... they paint the cars and they put new interiors in them. What you don't see on camera is the cars are painted horribly, not primed, not prepared properly. Those cars need to look good on camera, from a distance, for 2 minutes.

You can't paint a rust-bucket in a week. Each process from chemical treatment, epoxy prime, high build prime, straightening, color / clear, require cure time and sanding. Sanding? They don't do that. lol! They just load up their gun and shoot like the OK coral.


I would encourage you to consider the complexity of what you are trying to do, how much it will cost, and the likelihood of improving the Mission implementation. This isn't reality TV. If you want it to be good, it is going to take study, consideration, and design.

That is probably a second order Linkwitz-Riley design but a 2nd order LR network is schematically the same as a second order Butterworth and I don't recall the detail on what values determine which. It's been a long time since I designed networks and we have reached the limit of my knowledge. Unfortunately, I am in no position to spend time getting back up to speed.


In my very first engineering class, very first day, I sat "Introduction to Engineering" lecture given by an amazing prof who was a total freak in the best possible way. He stood in front of 250, 18 year old, self aggrandized, know-all assholes and he said, "Any number of people can build a bridge or a structure that will carry a given amount of weight. It takes an engineer to build a structure that will just barely carry it."

I share that as a nudge to consider that an engineer with knowledge and skill can design a network filter using affordable components that will out perform a layman implementation, the same way those cars you see at the shows with no hood, huge supercharger, massive cubic-inch, chrome and gloss everything... cannot come remotely close to the performance of a stock 2022 Corvette that cost half what the show cars cost to build. That is engineering.

 

[ukspawn]

All i want to do is CLONE the crossover with the same values.

dont worry about all that you said, just "is everything conencted to the right place" thats all i need. the rest is up to me to test and measure the values etc...

i dont know what you mean by 4 inputs without polarity. the polarity is as i stated in the comment above.. and i stated the wire with the colour line is negative terminal.. i marked out the polarity in my Xsim diagrams...

Its fine ill figure it out man, thanks

 

[Martaine2005]

seems like you want to break up a lifeboat for wood to build a raft so you can float off the island.

Brilliant, just brilliant!


Martin

 

[ukspawn]

im not breaking up the lifeboat im just building a raft alongside it and comparing the 2...

it seems people are more interested in talking me out of doing something i want to try instead of simply helping me to do it..

its really dissapointing on the internet to see this. but it is what it is

 

[ukspawn]

sorrry im a bit drubnk, no disrespect intended

 

[Martaine2005]

My apologies,
I don’t mean to sound horrible, but reinventing the wheel is pointless.
There are countless crossover calculators online which do a reasonable job but as some have already told you, simulations and real world tests are somewhat different. Having flying leads out the back of the speaker for cap changes is a good idea. I use a diy breakout board for op amps for the same reasons.
The only way you’ll know if there is a difference is to swap out the components for your choices.
Get a marker pen and draw the components under the board with a light (torch) shining from the opposite side. That should help you ‘see’ all the connected components and what’s connected to what. Then you can draw the schematic with confidence.


Martin

 

[ukspawn]

thank you, i feel thats what ive done with the picture by mirroring the front/back

all i need help with is just someone with experience to just say im doing it right or wrong

And its fine, i know the internet

thanks mate

 

[ukspawn]

its not jsut a crossover upgrade to upgrade and improve sound, its to keep me busy and keep me doing something, i need these things

 

[John Canon]

its not jsut a crossover upgrade to upgrade and improve sound, its to keep me busy and keep me doing something, i need these things

You have some good ideas. The Internet might react better if you actually tried out some of the first steps to see what you get. Nobody wants to spoon feed you through your ideas step by step ... that's your job. Talk about those steps you took and what you found out. Your questions should be the result of experiments, not conjecture. Make those decisions and those achievements yours. sorry that's all the emojis there are.

 

[ukspawn]

You have some good ideas. The Internet might react better if you actually tried out some of the first steps to see what you get. Nobody wants to spoon feed you through your ideas step by step ... that's your job. Talk about those steps you took and what you found out. Your questions should be the result of experiments, not conjecture. Make those decisions and those achievements yours. sorry that's all the emojis there are.

While I do agree and I feel that is what i am doing, there is a limit to trying something without checking first its correct with someone who has experience. It can damage equipment or even be fatal with the wrong capacitors etc, so some caution and reassurance i feel is only natural to seek.

I don't want spoon feeding anything, i feel since coming to this forum i have been given a lot of good information, i have learned so much.

What a capacitor is, how it works in a crossover, how to read different values and what they mean (like 475k vs 4.7uF X%) , what a resistor is and what it does and how to read them, what a inductor is how they work in a crossover and learning i need a special device (LCR) to measure them, and even that is still work in progress (Whats ESR how do i measure it etc etc)

So far im unable to do any experiment as so far all i have is all the replacment resistors... this is a "bit at a time" project that also gives me the time to do all this learning in the process of saving up and buying the parts bit-by-bit...

(not because im poor (although im not wealthy) but rather because I don't want to spend a large lump sum in one and then not know how to even use what i brought or risk buying the wrong things).

So all i needed was a "yes its fine" "no its wrong, try again, heres a tip/pointer"

but instead now we have 2 more pages of effort into explaining why or why we shouldnt be doing it or if its worth it or why its not people heres job to help me (?!) - thats fair enough, if people dont want to help there is no obligation and as i do with things i cant or dont want to do, i simply dont, i dont reply to it, dont get involved in it. thats just me. Its a forum youre welcome to say whatever you want.


A friend of mine has no idea about computer hardware, overclocking, configuration, setup, software etc... but he likes gaming, he wants his pc to perform as good as it can, look good and work without problems..

I have been building PCs since i was 7 years old and i have a whole LIFE of experience to draw on and help him build his PC, configure the UEFI/BIOS, install and configure windows and optimise its hundreds of hidden settings, install software and configure the proper graphical options etc etc

If i *want to help him* i will simply instruct him. Go here, donwload this, click this, set this setting, reboot and youre done.
He never asks why, he never questions if im about to break his PC he doesnt know, he trusts my years of experiance and he does not care, he just needs the help. If i dont feel like helping ill simply not (untill maybe a day when i feel like i do want to)

Iv not asked him to go look into XYZ , researtch this and that for him to come back and have 1000 more questions that he had to begin with, more confused and takes 5x longer than me simply giving him a direct answer or instruction to his question.

not saying anyone has that obligation to do that for me, but thats what i need now and again, just a little nudge from someone who already knows this. I dont particularly want to learn the ins and outs of every little aspect and nor should I if its not neccesary to achieve the end goal (succesfully or unsucessfully).

I dont feel my question "is my xover diagram correct compared to the original" (not in values of components etc, just are the "wires" connecting to the right "plugs" - yes, no

Then i can continue to learn. improve, etc

Iv come to a forum for help and i help where i can, in the way the person asks for the help. I dont tell them to "go and do it yourself" - if that was the answer they/i were looking for then they simply would not post in a forum asking.

Again, no im not saying YOU HAVE TO do as i want, answer what i want or even stop posting that im doing it all wrong or its a bad idea whatever, its a free place to post however you feel like posting, but its also a free place for me to ask a simple question and want a 'simple answer'.

another 12 paragraphs... my diagram is now burried and i still dont know if its right or wrong and if wrong what part...

Maybe ill never get anyone to look and tell me, maybe ill have to pay someone somewhere to look at it, maybe ill have to post on other forums and groups etc etc

it would just be nice to get "yeah, iv built loads of crossovers and that looks correct to the one you are trying to clone" or "iv done this for years, no its not right, youve put X backwards"

THANK YOU! - i can learn, and now make the change and know i wont damage my stuff/blow up my amp/speaker when i do eventually get all the parts and am ready to come asking for advice in soldering it all together or whatever i next cant figure out.

i dont want this to just become a forum/internet argument as i know is 'normal' im not new to the internet, forums and humans

im going to repost my diagram again below and see if anyone can help me see if it looks correct. if anyone doesnt want to help/look/check it for me thats absolutley fine. if you can or want to thats appreciated. other than that i dont require any other help right at this moment.

Thanks all for contributions. again im not being funny, just want to get to the answer to the question i have and not have 100 more instead.

Cheers,

 

[ukspawn]

i dont need to know if the values are correct, just are they connected to the right places in my Xsim drawing.

INPUTS at the bottom are as follows (using the rear PCB picture marked with white "input" - left to right) -

[LF- IN] [HM- IN] [LF+ IN] [HM+ IN]

also, the cables with the colour lines indicate the NEGATIVE connection.
If you cant see or need more info let me know.

Thank you

 

[roughshawd]

I'm sure there is a reason they put those 80uf caps in there. Either the speakers they used were seconds or cheap because someone scrimped on the amount of coil they should have, or they are multi speaker cabinets that have un-matched speakers in them and they had to stabilize the signal enough for all of them to work. I have heard about doubling a half sized cap to compensate for expensive components, It worrys me! I think maybe that someone did a fine fix it job once, using a really expensive component that was required and noone else would afford. Scares me in the fact that I have seen amps on the shelf sitting there smoking because someone decided to make the sound coming out of the speakers clearer..... and there is this rule of thumb (I like my thumb) use exact replacements when changing things.

 

[ukspawn]

thanks for the input.

the speaker is brand new and hasnt been fixed.
cant really speak to why they used 80uf other than thats what was needed to get theright roll-off etc