Electrolytic vs Tantalum

[R.G.]

You're right, John. 10V ought to be OK. It will be if one uses either batteries or well regulated 9Vdc supplies. A fresh alkaline battery will sometimes measure 9.4 to 9.6.

However, there is a contingent of effects users that want to "mod" effects by hooking them up to 12V or 18V. A 10V cap will be in trouble, especially at 18V. I've had to start specifying 25V caps for everything, purely out of "defensive medicine."

[frank_p]

Caps types in effects OFTEN don't matter as much because of the low voltage however some are microphonic and that can be part of the sound. something like a tone control cap in a guitar body with guitar amp speaker feedback going on. Example I installed pickups in a friends guitar and we tried different cap types and values film stacked and wound and ceramics.  The sound my friend liked was the stock large disk ceramic from the 70's that was microphonic.  I forget what lettering was on the cap for ceramic type.

The NPO ceramic discs are not microphonic, but they are bigger.

Sorry kinda of a side question  
I have lot's of 10v caps......I always use 16v in my builds...but was wondering if using the 10v would be OK? or is 10v to close  
The footprint is smaller and that would be a plus in some builds.

If the voltage in the circuit (where the cap is in the circuit) is 5vish then they should be fine and with some leeway.
If you are using them at 9v then you are pushing it. I'm sure they will be fine but your right on the edge and it would be
best to use a higher rated cap just in case.

If voltage rating (a cap can handle) goes down with time, wouldn't it be more secure to have some margin there ?

--------------

Also, an other question:  Is it true that smaller aluminum electrolytics have less time life, this due to thinner electrolytic layer ?

[edvard]

I bought some 1uf film caps recently, because when all it's doing is coupling signal, electrolytic is just overkill anyways (IMHO).
Save 'em for power supplies and filters.

BTW - those 1uf film caps were TINY.
I opened up the package and was like "Holy crap, did I order 1pf's accidentally?".
Nope, and they work just fine.


Woops, maybe I should have paid more attention to the tolerance.
+80/-20%?  
http://www.mouser.com/ProductDetail/TDK/FK28Y5V1C105Z/?qs=liFJyUJTUDGDO4oJ7GLD1w%3d%3d

[DavenPaget]

I bought some 1uf film caps recently, because when all it's doing is coupling signal, electrolytic is just overkill anyways (IMHO).
Save 'em for power supplies and filters.

BTW - those 1uf film caps were TINY.
I opened up the package and was like "Holy crap, did I order 1pf's accidentally?".
Nope, and they work just fine.


Woops, maybe I should have paid more attention to the tolerance.
+80/-20%?  
http://www.mouser.com/ProductDetail/TDK/FK28Y5V1C105Z/?qs=liFJyUJTUDGDO4oJ7GLD1w%3d%3d

That's a multilayer ceramic dude 

[edvard]

Aw, cripes... I totally missed that.
All this talk of film and I got carried away...

Anyways, they "sound" just fine, though I think I'd spend a little extra for better tolerance next time.

[DavenPaget]

Aw, cripes... I totally missed that.
All this talk of film and I got carried away...

Anyways, they "sound" just fine, though I think I'd spend a little extra for better tolerance next time.

Multilayer ceramics ... They are absolutely microphonic , any nearer to my amp and crazy feedback occurs .

[kvandekrol]

By my understanding, tantalums don't degrade over time the same way aluminum electrolytics do. We're talking 10 or 15 years down the road before electrolytics could potentially start going bad, but if you can get away with all tantalums in your design (e.g. the Keeley Compressor) then you're not going to have to replace the caps later. It's not that big a deal for us DIYers to have to change the caps a decade from now, but with all the tantalum hate, I thought I'd at least say something positive :)

This really only applies to caps from 3.3uF to about 22uF, though, because any smaller can be handled by film, and tantalums are hard to come by at higher values than 22 if you want to keep a safe voltage rating.

[PRR]

> tantalums don't degrade over time

My observation is that Aluminum electros die "quietly", maybe some ooze leaking; but Tantalum electros will sometimes die with a BANG. And older Tants seem to have a 20-year timer.

Most places we used Tant in the 1970s-1980s, today's improved Aluminum caps are IMHO a Better Part.

[jafo]

Oddly enough, I'd always heard that electrolytics sound awful and tantalums great. I haven't done enough part swaps to form a valid opinion, but I strongly suspect that in normal circumstances with modern parts, a capacitor is a capacitor. Maybe I'll experiment with a recording and some socketed caps.

[DavenPaget]

Oddly enough, I'd always heard that electrolytics sound awful and tantalums great. I haven't done enough part swaps to form a valid opinion, but I strongly suspect that in normal circumstances with modern parts, a capacitor is a capacitor. Maybe I'll experiment with a recording and some socketed caps.

I mean , seriously , after using electrolytics everywhere , how could you say electrolytics sound awful ? that's just wrong .

[jafo]

Oddly enough, I'd always heard that electrolytics sound awful and tantalums great. I haven't done enough part swaps to form a valid opinion, but I strongly suspect that in normal circumstances with modern parts, a capacitor is a capacitor. Maybe I'll experiment with a recording and some socketed caps.

I mean , seriously , after using electrolytics everywhere , how could you say electrolytics sound awful ? that's just wrong .

Agreed (although economics can justify suboptimal common practice). But I think I'm more disturbed that so few people are willing to do even basic experimentation.

[brett]

Hi
re: little ceramics

Multilayer ceramics ... They are absolutely microphonic , any nearer to my amp and crazy feedback occurs .

This is very unlikely if they are used for power supply isolation (e.g. near op-amps). In general, the feedback is physical and suitable mounting/packing of the board can greatly help. I've used them widely in low gain circuits for filtering and feedback, including in commercial applications, without problems.

Expanding on this - except for Gus' contribution, this thread has mostly lacked discussion of the use and purpose of the caps. Context helps lots. Otherwise we're having a discussion along the lines of: motorcycles or trucks -which are best?
cheers

[DavenPaget]

Hi
re: little ceramics

Multilayer ceramics ... They are absolutely microphonic , any nearer to my amp and crazy feedback occurs .

This is very unlikely if they are used for power supply isolation (e.g. near op-amps). In general, the feedback is physical and suitable mounting/packing of the board can greatly help. I've used them widely in low gain circuits for filtering and feedback, including in commercial applications, without problems.

Expanding on this - except for Gus' contribution, this thread has mostly lacked discussion of the use and purpose of the caps. Context helps lots. Otherwise we're having a discussion along the lines of: motorcycles or trucks -which are best?
cheers

You were saying ?
http://greygum.net/sbench/sbench102/caps.html

[GP]

Hi
re: little ceramics

Multilayer ceramics ... They are absolutely microphonic , any nearer to my amp and crazy feedback occurs .

This is very unlikely if they are used for power supply isolation (e.g. near op-amps). In general, the feedback is physical and suitable mounting/packing of the board can greatly help. I've used them widely in low gain circuits for filtering and feedback, including in commercial applications, without problems.

Expanding on this - except for Gus' contribution, this thread has mostly lacked discussion of the use and purpose of the caps. Context helps lots. Otherwise we're having a discussion along the lines of: motorcycles or trucks -which are best?
cheers

You were saying ?
http://greygum.net/sbench/sbench102/caps.html

I think Brett was addressing your assertion of microphonic behaviour. Your link (and subsequent links) has absolutely no data regarding microphonics.

[DavenPaget]

Assertion ? 
You kidding bro ? i have a stratoblaster with a 1.5uf output monolytic and it is very microphonic .

[frank_p]

http://www.electro-tech-online.com/general-electronics-chat/26407-electrolytic-caps-vs-tantalum-caps.html

[diagrammatiks]

not all ceramic caps are created equal.

5 cent jelly beans in high capacitances will most likely suck in all ways.

that 80/20 tolerance isn't so hot either.

on the other hand a nasa quality space approved .1 tolerance glass porcelain cap will be the tits.

[DDD]

I have to say that NOT 100% of the 9-Volt stompboxes are "are indifferent" to the type of electrlytics.
For example, the famous Harmonic Percolator and it's numerous clones work absolutely different with one of their caps changed with Tantalum/Alu.

[amptramp]

not all ceramic caps are created equal.

5 cent jelly beans in high capacitances will most likely suck in all ways.

that 80/20 tolerance isn't so hot either.

on the other hand a nasa quality space approved .1 tolerance glass porcelain cap will be the tits.

Not all tantalums are created equal, either.  The most common are the dry-slug tantalums which have the characteristics that have been mentioned: low leakage current, excellent high-frequency performance, small size, inability to self-healand tendency to explode when fed by a low-impedance source like a power supply.  There are also wet-slug tantalums which are able to be used on power supplies but will short out if subjected to more than 0.3 volts in a reverse direction.  There are tantalum foil capacitors which are usually available in larger capacitances and sacrifice high-frequency behaviour for compact size.  Then there are tantalum-case tantalum capacitors that are excellent for power supply bypassing.  I used these on a power supply filter for the Shuttle-mounted power supply "dock" for the Hughes GOES series satellites and the attenuation came within 1 db everywhere and 0.5 db in most places.

[wavley]

not all ceramic caps are created equal.

5 cent jelly beans in high capacitances will most likely suck in all ways.

that 80/20 tolerance isn't so hot either.

on the other hand a nasa quality space approved .1 tolerance glass porcelain cap will be the tits.

I use space rated multilayer and parallel plate ceramic caps with gold bond terminations in high frequency cryogenic amps for radio astronomy every day, and yes, they are the tits.

These guys make awesome stuff http://www.atceramics.com/