The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
electrolytic recapping (replacing tantalum) question Utility Plugins
Old 26th January 2010
  #1
Lives for gear
 
otobianki74's Avatar
 

electrolytic recapping (replacing tantalum) question

doing a mod to my a-tron 110 board and am switching out the opamps and replacing tantalum capacitors with the electrolytics at the same values.

just a general question...

on the capacitor side there were many different brands to choose from with different specs (i.e. temperature, tolerance).

we went with nichicon caps. these were aluminum capacitors, but there was a sub category in the same section indicating differences such as "general usage" or "low leakage."

do these make a difference?

we ended up going with the ones which had a smaller swing tolerance percentage (+/-10% instead of +/-20%). also these were labeled "low leakage" instead of "general purpose." will these differences matter?

also, there were a few tantalum caps at 6 volts which weren't available as electrolytics so we ran with 6.3 volts (all other values the same). any issues on that end?

thanks for any help techs!

oto
Old 26th January 2010
  #2
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by otobianki74 View Post
doing a mod to my a-tron 110 board and am switching out the opamps and replacing tantalum capacitors with the electrolytics at the same values.

just a general question...

on the capacitor side there were many different brands to choose from with different specs (i.e. temperature, tolerance).

we went with nichicon caps. these were aluminum capacitors, but there was a sub category in the same section indicating differences such as "general usage" or "low leakage."

do these make a difference?

we ended up going with the ones which had a smaller swing tolerance percentage (+/-10% instead of +/-20%). also these were labeled "low leakage" instead of "general purpose." will these differences matter?

also, there were a few tantalum caps at 6 volts which weren't available as electrolytics so we ran with 6.3 volts (all other values the same). any issues on that end?

thanks for any help techs!

oto
Tantalums generally have better HF impedance than aluminum so if replacing caps used in PS decoupling, you may need to add small ceramic discs in parallel. Alternately, the new aluminum low Z switching PS caps may effectively sub for tantalum in PS decoupling.


JR
Old 26th January 2010
  #3
Lives for gear
 
otobianki74's Avatar
 

Quote:
Originally Posted by JohnRoberts View Post
Tantalums generally have better HF impedance than aluminum so if replacing caps used in PS decoupling, you may need to add small ceramic discs in parallel. Alternately, the new aluminum low Z switching PS caps may effectively sub for tantalum in PS decoupling.
thanks JR. I will have to follow up with my tech on this, but this is definitely noteworthy. especially given that we were recommended this mod as the tantalums on the power rails fail to short, rather than open. we were told that if one of the modules takes a **** and that component dies, it will try and take down adjacent modules.

in the case of this type of mod will what I mentioned in my original post work in terms of specs on the caps?

thanks.

oto
Old 26th January 2010
  #4
Lives for gear
 
brianroth's Avatar
 

I am "with" John here....the higher quality aluminum electrolytics are designed for the same applications as tantalums. But, in a critical application (as in power supplies for high speed digital, video, etc), you might have to parallel the replacement aluminum lytics with a low impedance 0.1 uF "something".

Oddly enough, the "something" might be a monolythic ceramic, which, like a tantalum, ALSO can fail as a short circuit across power supply rails.

To be honest, I am not exactly sure what you are re-capping. If it's a purely analog device, than a decent Nichicon should work well. I prefer caps rated at 105 degrees C since they will (in theory) last longer than a cheaper 85C part...everything else being equal.

Best,

Bri
Old 26th January 2010
  #5
Lives for gear
 

Hi
I know of lots of 'monolythic ceramic' types that fail, probably 'batch' issues as they were 50 Volt working used at 17 Volts.
The number of tantalum failures, while they can be spectacular, is pretty few.
Proper designers will think 'what if' and have contingency plans.
Matt S
Old 26th January 2010
  #6
From what I understand, Nichicon HE and Panasonic FM are tantalum replacement, or substitutions.
Old 26th January 2010
  #7
Lives for gear
 
JohnRoberts's Avatar
 

I have encountered short circuit failures with low Z aluminum too, but not as spectacular as the old tantalum fireworks, and perhaps related to the specific switcher design I was working with, and fact that low Z aluminum was a relatively new technology at the time. Hopefully they are more robust now.

In consoles I always used small flameproof resistors (as fuses) on every strip in series with power feed, so one channel failure doesn't take down the whole console. Shorted ICs were the more common failure mode, but I haven't used tantalum caps in maybe 30 years.

JR
Old 26th January 2010
  #8
Lives for gear
 
dualflip's Avatar
 

Quote:
Originally Posted by Sean Sullivan View Post
From what I understand, Nichicon HE and Panasonic FM are tantalum replacement, or substitutions.
+1 on that!, Nichicon HE or Panasonic FM (also FC) are the only way to go when it comes to audio. There are a lot of other brands of course, but i mean if you go with Nichicon or Panasonic i would only choose HE or FM (FC), not only by the fact that they are good sounding capacitors but for example the FM's are rated 7000hrs at 105º C !!, meaning they will outlast most capacitors out there, specially in applications such as a console where they tend to heat up.

I rather go with Panasonic FM, they have better specs than FC and they are cheaper than FC and Nichicon HE. I use the FM's in every piece of audio equipment i have to recap.
Old 26th January 2010
  #9
Lives for gear
 
mexicola's Avatar
 

Quote:
Originally Posted by dualflip View Post
+1 on that!, Nichicon HE or Panasonic FM (also FC) are the only way to go when it comes to audio. There are a lot of other brands of course, but i mean if you go with Nichicon or Panasonic i would only choose HE or FM (FC), not only by the fact that they are good sounding capacitors but for example the FM's are rated 7000hrs at 105º C !!, meaning they will outlast most capacitors out there, specially in applications such as a console where they tend to heat up.

I rather go with Panasonic FM, they have better specs than FC and they are cheaper than FC and Nichicon HE. I use the FM's in every piece of audio equipment i have to recap.
+1
Old 26th January 2010
  #10
Lives for gear
 
otobianki74's Avatar
 

great info guys, thanks guys.

how do you determine whether or not caps are HE, FM, or FC's? these don't seem to be indicated on the mouser site.

for example, this is one I ordered:

UKT0J470MDD Nichicon Aluminum Electrolytic Capacitors - Leaded

thanks!

oto
Old 26th January 2010
  #11
Lives for gear
 
dualflip's Avatar
 

Quote:
Originally Posted by otobianki74 View Post
great info guys, thanks guys.

how do you determine whether or not caps are HE, FM, or FC's? these don't seem to be indicated on the mouser site.

for example, this is one I ordered:

UKT0J470MDD Nichicon Aluminum Electrolytic Capacitors - Leaded

thanks!

oto
Mouser does distribute the Nichicon HE, just type Nichicon HE in the search window and select the measures.

As for the Panasonic FM and FC, the only distributor i know that has them is digikey, DigiKey Corp. | Electronic Components Distributor | United States Home Page
Old 26th January 2010
  #12
Rubycon ZA are best, but only available to 25 volts. Then they go to the ZL series, identical to Panasonic FM and Nichicon HE. The Rubycon ZA's are available in smaller values than either Panasonic or Nichicon.

Better yet is just yanking them out via the use of low bias current precision opamps. The best sounding capacitor is no capacitor.

Jim Williams
Audio Upgrades
Old 26th January 2010
  #13
Gear Head
 

Quote:
Originally Posted by Jim Williams View Post
Rubycon ZA are best, but only available to 25 volts. Then they go to the ZL series, identical to Panasonic FM and Nichicon HE. The Rubycon ZA's are available in smaller values than either Panasonic or Nichicon.

Better yet is just yanking them out via the use of low bias current precision opamps. The best sounding capacitor is no capacitor.

Jim Williams
Audio Upgrades
Are these caps just Low Z/long lasting versions or is there something else special about them? I am checking the data sheet on the Nichicon PW series opposed to the HE series and they seem to be identical except the life expectancy.

Richard F.

Any info would be greatly appreciated.
Old 26th January 2010
  #14
Look at the impedance vs frequency curves. There's quite a difference. These new formulas are 1/3 the impedance of tantalums. Not all data is printed in the Digi-Key catalog, go to the manufacturers' web sites for that.

Jim Williams
Audio Upgrades
Old 26th January 2010
  #15
Gear Head
 

Thanks Jim,

Just to clarify, are you talking about a big difference in tantalum vs. electrolytic caps?

To clarify my question, I was trying to find out if there was a difference between the PW and HW Nichicon caps other than life expectancy. The Nichicon website isn't allowing me to get to the data sheets at the moment.

Thanks again!

Richard F.
Old 27th January 2010
  #16
Dipped tantalum caps are dry slug types, they don't dry out and can last for decades. El caps will all eventually fail over time. Tant's can't take more than 5% reverse voltage. Any more and poof! Don't breath, those fumes are poisonous.
El caps can take up to 20% reverse voltage. When they go, it's more like a party popper, lot's of fun!

In that regard they are a better choice for DC blocking in audio coupling circuits as many times offsets from opamps can reverse a bit, especially in EQ circuits with positive AND negative gain. The sonics are also a bit more forgiving, maybe slow but not objectionable. Tantalums sound like they look, cold and hard. Their main advantage besides lifetime is they are smaller and can have both low leakage and low impedance, something the El caps have yet to combine.

So, flip a coin?

Jim Williams
Audio Upgrades
Old 27th January 2010
  #17
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by Jim Williams View Post

Better yet is just yanking them out via the use of low bias current precision opamps. The best sounding capacitor is no capacitor.

Jim Williams
Audio Upgrades
Something we can all agree about...

Only downside for professional applications is DC coupling does not protect against failure in earlier stages... that can get expensive if power amps are DC coupled too.. (speakers don't like DC). Good to protect against DC at least in the power amp. While that can be done with a relay instead of a blocking cap if really serious.

JR
Old 28th January 2010
  #18
Lives for gear
 
otobianki74's Avatar
 

thanks jim and everybody else for all the info. I'm still a little confused about Fritzkrieg's question.. seems to have gone unanswered.

"To clarify my question, I was trying to find out if there was a difference between the PW and HW Nichicon caps other than life expectancy. The Nichicon website isn't allowing me to get to the data sheets at the moment."

as his previous post mentions also:

"Are these caps just Low Z/long lasting versions or is there something else special about them? I am checking the data sheet on the Nichicon PW series opposed to the HE series and they seem to be identical except the life expectancy."

from what I can tell he's trying to clarify if the only difference between the HE and PW specs are life expectancy. the data sheets I looked at seemed to indicate the same thing. for my case, the PWs are the only ones that have the correct specs for the tants I'm trying to replace.. doesn't seem like the HE ones come in the specs which I need. so this is an important question for me too.

thanks!

oto
Top Mentioned Products
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
brewery / Geekslutz forum
19
wallace / So much gear, so little time
5

Forum Jump
Forum Jump