Hotrodding the UCD modules

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#522
Decoupling caps?

The caps in question are multi purpose. They are across the regulators zener diodes so are to filter out noise. They are also on the bases of the regulator transistors so serve as the cap to be multiplied in this cap multiplier configuration. They will only see 12V unless something fails so a 16V oscon type would be very suitable here.

Chris,
Super E??
Roger
 
#523
Yves Smolders said:
Most of the UcD thread contain lots of information, but spread all over, hard to find (or even remember) if something was said or done before 😀

I'm sorry I'll look it up!
Click to expand...

They all do. The concerns are two. One is that by repeating the same questions you further dilute it. The other is they're only going to want to answer the same questions so many times before they find that their time is best spent elsewhere.

The UCD cap arrangment was also posted in this very thread, you're not alone Yves. Seems people expect others to make more of an effort than they do, something is wrong there. Everyone considering these mods should at least take the time and figure out what they're playing with too (read the thread).

Roger,

http://www.octave-electronics.com/Parts/cap/bg_tech.shtml#7

Found it on google after it was mentioned a few posts back, sounds interesting I think.

Regards,
Chris
 
#524
The concerns are two. One is that by repeating the same questions you further dilute it. The other is they're only going to want to answer the same questions so many times before they find that their time is best spent elsewhere.
Click to expand...

They could for example spend some of their time on writing a FAQ and better manuals and documentation!

Hypex can of course choose how much information they give to tweakers. But the information given to "normal" customers is also very limited and hard to find.
Example: Somewhere in the UCD180 or UCD400 threads Hypex says that any responsible manufacturer would encourage users to make sufficient dc-protection circuits in their amps. But have a look at the UCD400 user manual. Only one page long and not a word about dc-protection, only a connection diagram without dc-protection!

I know that most questions are answered many times in the huge threads, and that most problems can be solved by using the Hypex PSU:s. But I still think that the current documentation is poor and that they should make an effort to collect at least the most important information into more complete manuals or an faq.
 
#525
Thomas,

I agree. Hypex make very good products but documentation is quite limited. Hypex should do FAQ. Example you gave about DC-protection is good. Suitable /good DC-protection connection is not easy to find.

PS.
If my memory serves, Bruno has said they do not want to give dc-protection connection they use in their PS. modules, because they are affraid to get too much e-mails concerning this issue.


PS2. It is much easier to find something from these threads when you select: Show Printable Version+ Show all xxx posts from this thread on one page
 
#526
Posting a problem??

Yes this forum format is not perfect but I do think it is the best or I wouldn't be here. There is a tremendous amount of useful information in here to be read but that is the problem, information retrieval. People are just too lazy to read it all, don't have the time or even have to translate it. I see no easy solution except hooking up a good search engine would certainly help. Wonder what the chances of that happening are? Think of an intelligent supervisor that would automatically direct questions to a prior post if it has been asked before. Now anyone want to write the code?
Roger
 
#528
You really can't use them at all, unless for some reason you want to limite your rails to say 40Vdc worst case.
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I'm refering to use in the UCD180. The standard Hypex part in that location is 470uF 50V and rated at 85 deg C. The recommend voltages for these modules by Hypex is between 30 & 45V with voltage protection kicking in at 52V. Bruno obviously felt a 50V part here was sufficient and I'm recommending simply TRYING a part that is rated at the same voltage and HIGHER tempeture (105 deg C) as the stock Hypex part.

I've got a set installed in a 2-channel UCD-180 with 40V rails. That is more than 20% headroom over the rail voltage. I fail to understand why you think that is a dangerous recommendation?
 
#529
different PS caps parallel

Is it ok to use different brand but same size/voltage caps in power supply?

I have in hand 10 000uF/63V Rifa PEH200 and Chemi-con SMH:s.
I plan to use them parallel in 4xUCD180 woofer amp (one channel to each Orions XLS10).
 
#530
Cap question

I see no problem with this except I wouldn't mix them as they all do have a different sound. Using 2 caps per rail is a different story. Here mixing them might very well help balance out the sound differences. Not knowing your configuration I can’t comment further.
Roger
 
#531
As you probably noticed with my previous message, seraching information on this thread, or on the two ucd180 and ucd400 threads it's very time consuming nowadays, cause we have a total of more than 300 pages to search. Things like the signal coupling capacitors position, the dos and don'ts of op-amp upgrade, PSU Cap upgrade and LC filter cap upgrade, are lost in the middle of a ton of posts, and even when you fid it, you have to read the whole thing cause some information changed as the models evolved...

We definitly need a FAQ, with controled content, that keeps all this knowlodge in one place, easy to read. If Jan-Peter can't do it for obvious reasons(not posting too much info for tweakers on their page), then we should...

Allan

ps. There are only two people interested in sourcing the Slit-foil capacitors from outside the EU? I'll end up being forced to use normal caps... :-(
 
#533
Kevin P said:


I'm refering to use in the UCD180. The standard Hypex part in that location is 470uF 50V and rated at 85 deg C. The recommend voltages for these modules by Hypex is between 30 & 45V with voltage protection kicking in at 52V. Bruno obviously felt a 50V part here was sufficient and I'm recommending simply TRYING a part that is rated at the same voltage and HIGHER tempeture (105 deg C) as the stock Hypex part.

I've got a set installed in a 2-channel UCD-180 with 40V rails. That is more than 20% headroom over the rail voltage. I fail to understand why you think that is a dangerous recommendation?
Click to expand...

I'm aware you're talking about the UCD180, I'm also aware you likely have an older version module.

Maybe before when the overvoltage protection was something like 47 volts, the caps were 50 volts. I hope not but, it's possible.

That'd be the kind of margin I'd be fixing as a tweak, not tolerating.

At some point in time the overvoltage on the module was increased to something more reasonable, and the current versions that have overvoltage trip at 52 volts, come with 63 volt, 105 deg C. caps. If anyone with that overvoltage level took your advice and used 50 volt caps on their module they'd blow right off the board, and in your first post you never mentioned limiting the rail voltage to no more than 40, worst case, inviting disaster.

You should also keep in mind that seeing the module shut down on overvoltage does nothing at all to protect the caps on it from damage. They're still in the circuit and seeing full potential, which is very damaging to them. Using 50V caps with an overvoltage set to trip at 52 is crazy talk.
 
#534
ninjanki said:
As you probably noticed with my previous message, seraching information on this thread, or on the two ucd180 and ucd400 threads it's very time consuming nowadays, cause we have a total of more than 300 pages to search. Things like the signal coupling capacitors position, the dos and don'ts of op-amp upgrade, PSU Cap upgrade and LC filter cap upgrade, are lost in the middle of a ton of posts, and even when you fid it, you have to read the whole thing cause some information changed as the models evolved...

We definitly need a FAQ, with controled content, that keeps all this knowlodge in one place, easy to read. If Jan-Peter can't do it for obvious reasons(not posting too much info for tweakers on their page), then we should...

Allan

ps. There are only two people interested in sourcing the Slit-foil capacitors from outside the EU? I'll end up being forced to use normal caps... :-(
Click to expand...

Allan, I know its a pity nobody wants the slit-foils, me neither. Find them far too expensive for a maybe improvement. Over €30,- a piece is just outrageous to me. And maybe they're old to. Too much risc. I exchange my caps. every 8 years.

And it would be nice to have a FAQ with f.i. UCD categories dividing in cap. improvements, PSU's, wiring, housing, opamps,etc.
 
#537
You should also keep in mind that seeing the module shut down on overvoltage does nothing at all to protect the caps on it from damage. They're still in the circuit and seeing full potential, which is very damaging to them. Using 50V caps with an overvoltage set to trip at 52 is crazy talk.
Click to expand...

I guess Hypex and I are both crazy then. 🙂

I'm not advocating that you run the things overvoltage. The protection circuit is for emergencies, not for normal use. I'm running them with over 20% safety margin. As for other people I assume if they are building and modifying amplifiers they can figure out what their line voltage is going to be and choose an appropriately rated capacitor.

I think you are missing the point of my post. I was just offering up another capacitor choice that people might want to check out. I don't sell them... I'm not offering up any subjective advice. I'm just letting people know that they are available and that their specifications are attractive in comparison to the FC line. In addition, I stated their voltage rating limitations. I'm not sure what other qualifiers I need to make before submitting a post.
 
#539
Lighten up!

classd4sure said:


I'm aware you're talking about the UCD180, I'm also aware you likely have an older version module.

Maybe before when the overvoltage protection was something like 47 volts, the caps were 50 volts. I hope not but, it's possible.

That'd be the kind of margin I'd be fixing as a tweak, not tolerating.

At some point in time the overvoltage on the module was increased to something more reasonable, and the current versions that have overvoltage trip at 52 volts, come with 63 volt, 105 deg C. caps. If anyone with that overvoltage level took your advice and used 50 volt caps on their module they'd blow right off the board, and in your first post you never mentioned limiting the rail voltage to no more than 40, worst case, inviting disaster.

You should also keep in mind that seeing the module shut down on overvoltage does nothing at all to protect the caps on it from damage. They're still in the circuit and seeing full potential, which is very damaging to them. Using 50V caps with an overvoltage set to trip at 52 is crazy talk.
Click to expand...
Chris,
It really is not that big of a deal especially with 105deg caps. They can run reliably at 10% over forever, been there done that! The specs are also with the caps running at rated ripple current which these will never see. The over voltage causes more leakage current therefore more internal heat. This is not usually a problem on low voltage caps like these as the extra heat won’t be much. Now if we were talking about 450-500v caps that would be a different story as the leakage don’t have to be much to generate enough heat to cause failure. In this particular case due to the recommended caps lower ESR they probably will run cooler than standard 63v caps leakage and all. Point is the simple finger temp test would verify whether or not they are a viable option. Also remember they will reform to the higher voltage in time if they don’t get too hot.
Roger
 
#540
Kevin Haskins said:


I guess Hypex and I are both crazy then. 🙂

Click to expand...


I don't think Hypex is crazy.

Kevin Haskins said:


I'm not advocating that you run the things overvoltage.
Click to expand...

No, you advocated replacing 63 volt caps for 50volt caps, even when you know overvoltage is at 52 volts.

Kevin Haskins said:


I'm running them with over 20% safety margin. As for other people I assume if they are building and modifying amplifiers they can figure out what their line voltage is going to be and choose an appropriately rated capacitor.
Click to expand...

You're confused. You're running the modules at over 20% margin with respect to its overvoltage trip point, not your cap's rating. You never recommended lowering the voltage when you recommended them as a viable altnernative. I even gave you an out by saying you must have an older version, which might have originally had 50 volt caps, and informed you that that's not the case for most modules.

I think you make a big assumption that everyone who reads that will know enough to lower the rail voltage.

In addition, I stated their voltage rating limitations.
Click to expand...

In context you stated their limitations:
"At least you can use them on the UCD180s for the power supply caps and as low voltage decouplers."


.. with respect to their use in the UCD400, and said they'd be a 1 to 1 replacement for the 50 volt 85 deg. caps :
" The standard Hypex part in that location is 470uF 50V and rated at 85 deg C."

..when they're in fact 63 volt, 105 deg. caps.

You're logic on the 52 volt trip level giving you enough margin of safety on 50 volt caps was clearly flawed.

I'm not sure what other qualifiers I need to make before submitting a post
Click to expand...


You could try having your facts straight. I see no point in further debating this with you.

Hi Roger,

I'm all out🙂

"The specs are also with the caps running at rated ripple current which these will never see. The over voltage causes more leakage current therefore more internal heat. This is not usually a problem on low voltage caps like these as the extra heat won’t be much."



While on the grande scale of things 50 volts qualifies as "low voltage" I'm not personally comfortable with the term as it applies to small margins of safety and while operating them overvoltage. I wont' advocate that myself. I've never blown up a cap Roger, sound practice goes beyond twisting wires.

You say yourself :

" The over voltage causes more leakage current therefore more internal heat. "

More internal heat leads decreased lifespan, rule of thumb for every ten degree increase= life/2.

"In this particular case due to the recommended caps lower ESR they probably will run cooler than standard 63v caps leakage and all. "

I don't like designing with "probably" with respect to calling it good enough for the job.

Increased leakage and internal temperatures can lead to caps venting as you know, possibly explosively. The whole point to using 105 deg caps is exactly for a longer lifespan, I see no reason to give that away by turning around and running it hotter.

"Rapidly reform" is exactly the cause which will lead to a rapid breakdown of the oxide layer, heavy current flow, likely well beyond it's rated ripple, rapidly boiling the electrolytic, and venting.

I thought the point of this thread was to not make dangerous mods, and certainly not advising others to make the same mistake.

They were also mentioned for use as the main PSU caps, that's not a little grenade.

If I'm wrong in that I'll stay wrong, with a smile on my face and all my caps on the PCB in one piece.

I'm going back to the UCD400 thread 😉
Regards,
Chris
 
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