box vs film caps (if that even makes sense)

[ham_phist]

Hey all,

In doing some looking at components and stuff, as well as looking at some different layouts, I am wondering when does one opt for the poly "box" type caps vs the "greenies" or other similar shinier, round type film caps? How do I know which to use when looking at a layout?

Thx
Randy

[Chris60601]

Essentially, there isn't a difference between the two. At first, I prefered using box, but since, I prefer using film.

I don't use the greenies although I seem to have a tone of them. But in reality, you use what you have *that only applies to the use of film vs box.

Knowing when to use either of the mentioned against electros and ceramics, that's another thread buried within these friendly confines'

---

From: [hidden email]
Sent: ‎10/‎6/‎2015 11:14 PM
To: [hidden email]
Subject: box vs film caps (if that even makes sense)

Hey all,

In doing some looking at components and stuff, as well as looking at some different layouts, I am wondering when does one opt for the poly "box" type caps vs the "greenies" or other similar shinier, round type film caps? How do I know which to use when looking at a layout?

Thx
Randy

---

If you reply to this email, your message will be added to the discussion below:

http://guitar-fx-layouts.42897.x6.nabble.com/box-vs-film-caps-if-that-even-makes-sense-tp25024.html

To start a new topic under Open Chat, email [hidden email]
To unsubscribe from Guitar FX Layouts, click here.
NAML

[rocket88]

long story short box and film caps are the same. the only difference is the footprint they take up on the board. i've got a bunch of greenies, but don't use them cause the higher values get huge, so i only use the ones that i can't get the values in box caps or the panasonic ones. typically i use the red panasonic 63v poly, as they are small and high quality. i don't  really use box caps as they can be fairly expensive, and don't really find they save much space compared to the panasonics. i haven't really seen round poly caps, except the axial ones, which are able to make larger spans.

as chris pointed out it's been covered in another thread, but when looking at a layout you can tell the cap type by it's value:

1pf-999pf: ceramic or multilayer ceramic (multilayer ceramics are less likely to become microphonic)
1nF-1uF: poly
1uF-1000uF: electrolytic (usually seen as round on the layout and show polarity)

[Frank_NH]

One little tidbit I read recently is that ceramic disk capacitors are preferred for voltage supply filtering.  For example, if a circuit has a 100 nF filter cap to ground for Vref, use a ceramic.  I had been using a box cap for this, but will start switching and maybe retrofitting some of my older builds.  Whether it makes a big difference in power supply noise suppression will depend on the specific circuit.

[Muadzin]

ham_phist wrote

Hey all,

In doing some looking at components and stuff, as well as looking at some different layouts, I am wondering when does one opt for the poly "box" type caps vs the "greenies" or other similar shinier, round type film caps? How do I know which to use when looking at a layout?

Thx
Randy

below 1nf, ceramics
below 33nf, greenie film caps
up to 1uf unpolarized, box caps or multilayered ceramics
1uf polarized to 10uf tantalum, above that electrolytics

Mostly its about cost, as mlcc's are so cheap. Plus they take almost no space at all, as greenies from 33n onwards and box caps above 470n start getting bigger and bigger. For polarized caps I prefer tantalums as electrolytics tend to degrade more with time, but even there cost is a limiting factor as the values get bigger. Plus its harder to get high voltage tantalums in higher values.

[tabbycat]

buy some cheap kits from ebay and play with them. for £6 you can cover a ton of bases with ceramics and greens, and fill in the gaps with odd values and fancy stuff as and when.

http://www.ebay.co.uk/itm/278-Pcs-30-Values-Polyester-Film-Capacitor-Assorted-Assortment-Kit-470pf-470nf-/251506641374?hash=item3a8ef6c9de

http://www.ebay.co.uk/itm/30-Values-300pcs-Ceramic-Capacitor-2pf-0-1UF-Assortment-Kit-MA-/171937379038?hash=item28084432de

as to deciding which type to use and when, if it's a clone i tend to look at the original. for example lots of cap snobs are down on ceramics but quite a few vintagey clones i've built have been exclusively ceramic apart from the electros (1uf and above). fender blender may have been one of them. ad50 another. can't remember which now. but if the original pcb was ceramic i go ceramic, same with film. if they sounded crap i would try another but they invariably sound amazing.
in my head i tend to have a kind of idea that for modulation films (greenies or box) are better suited as they are claimed to be a bit cleaner. whereas for fuzz and dirt ceramics are an option too as a little noise may add to the texture. but there is a lot of cork sniffing out there in cap land, so i may have just caught that prejudice from reading too much into too little too often (see last link in this post).

greenies are pretty good caps i think, miro describes them as 'underrated' in his component guide http://tagboardeffects.blogspot.co.uk/p/components.html which is why i suggested the above kit.
but they can get big from 100nf so if you have a few bunched up you may need to plan a bit before soldering.

and finally...

The 'Sound' of Capacitors..
http://www.freestompboxes.org/viewtopic.php?t=8625

[Beaker]

Multilayer Monolithic Ceramic are your friend!

Tiny, quieter than normal ceramic discs, and super-cheap. You can easily replace any and all poly film (greeny),  poly box and even small value (up to 10uF) electrolytics with these little guys. Only possible disadvantage is the fairly short legs.

Do yourself a favour, and get a selection like this (I bought one from this seller);

http://www.ebay.co.uk/itm/10pf-10uf-600pcs-30value-Multilayer-Monolithic-Ceramic-Capacitor-Assorted-Set-/111022072323?hash=item19d96e6203

These will last you a while, and give lots of "tweaking" values.

When you run out, order by the hundred - I have just run out of 1nF, so ordered a bag of 100 from China for £2. Bargain!

[Frank_NH]

Hmmm...those look great.  May have to get an assortment.  I've discovered that when it comes to < 1nF ceramics, small is good (i.e. I prefer a 0.1" nominal lead spacing)!  

[Beaker]

I would go as far as to say that every aspiring pedal builder should have a multilayer assortment.
They really are invaluable - and so stupidly cheap! £1.99 with free shipping (that's about $2.30) for 100 caps makes them about one tenth of the price of poly box caps.

I personally hate poly film caps, they are just too bulky for many builds, and I loath having to try and get them to lay down flat, to avoid having them sticking out the back of a 1590B.

Here's a pic of a recent build, a Madbean Sharkfin. I only used multilayers on this one (except for the electrolytics).

[IvIark]

Frank_NH wrote

Hmmm...those look great.  May have to get an assortment.  I've discovered that when it comes to < 1nF ceramics, small is good (i.e. I prefer a 0.1" nominal lead spacing)!

Yes I always try to go for 2.5mm spacing <1nF too.  Most caps higher value than that have been put in the layout assuming a 5mm spacing and so they're better suited.  Although I did find a source for 2.5mm spacing multilayers too and ended up getting both types so I've pretty much always got the right size for the build.  Add multilayer axials to the mix and you have a low profile cap for any occasion. They may not look the coolest but they're definitely my fave to build with.

I ended up getting a big compartment box and 500 of each of all the common values.  I don't think I'm ever likely to run out just building a couple of things a year for myself

[Chris60601]

BEAKER!!!!

You magnificent beestard, you!!!

I looked into this. Yanno, I loved the box caps but since moved to the chick-let types. Loved them too BUT,
I dunno why I never considered a full supply of these Multi-Mons!

Got my order in from Tayda today and can't wait to move to them as my source for low profile parts.
While I still order my electro (low profile, of course) from Smallbear, these Mono's will fill the need to keep my PCB's on the small side!!!!

Outstanding and thank you!!!

Cheers
Chris

[Beaker]

  

Glad I could help Chris!

[pyreweb]

Hello, many of the above replies have been useful to me, so thank you. Can I ask where Mylar capacitors fit into the mix please?

[Beaker]

Mylar caps are the type of caps referred to in the posts above, as poly film caps or "greenies".

[Zanius]

In my short experience I only ordered a bunch of greenies once. They look pretty cool and every time I take one out of the bag I swear I wanr to chew em. They look just like delicious gum
Don't think I'm gonna order more though, I find them too bulky especially after 50nf or so. Not to mention the poisonous hazard

[pyreweb]

Sorry, I was just going from this page (http://www.bitsbox.co.uk/index.php?main_page=index&cPath=65_76) and guessed that 'greenies' were the polybox ones as they look green in the pictures. Thank you, I will try to get hold of some.

[Drey]

Interesting...

"MLCC capacitors use "class II" dielectrics which are very highly polarizable ceramics like Barium Titanate. These cause MLCCs to suffer from a number of non-ideal behaviors like variation of capacitance with applied voltage, as well as less stable capacitance over temperature and piezoelectric behavior (they can act like tiny microphones and speakers). When a DC bias voltage is applied, their capacitance goes down over time until it settles to a new value. When the bias is removed, the capacitance will go partially back but not entirely - there is some hysteresis. This can be fully reversed by heating them up and allowing them to cool back down - a form of annealing. Even the best MLCC class II capacitors, those whose EIA designator begins with the letter X (like X5R) have about a 40 or 50% reduction in capacitance from 0V bias to half of their rated voltage. They end up at something like only 20% of the rated cap value at full rated voltage. Like Tantalums, they can also fail shorted, but usually not as dramatically as tantalums. MLCCs often have even LOWER ESR than a similarly-sized Tantalum cap. So, MLCCs have definite advantages and disadvantages. Pretty much the only area where it still makes sense to use Tantalum caps is when you need a stable, large capacitance in a small size. If you don't care so much about size, metal film caps are superior."

Another article that kills the multi layer ceramic capacitors for audio use

http://www.eetimes.com/author.asp?section_id=183&doc_id=1279709

[Chris60601]

I wonder how this really plays out in relationship to automotive grade, high grade and gen-purpose.
Then again, most of use build for ourselves so I really don't think this is as big as issue as the article makes out.

On another thought ... Looks like I wont be building any pedals that make use of Power Over Ethernet, Damned it!

[rocket88]

I don't really agree with the article at all based on my experience. I'm not saying it's wrong or flawed logic, just saying from my own builds and a lot of more prof builders then me use them without any issue. But I could be wrong.

[Drey]

6% Distortion at 10 Hz is a lot. With distortion circuits and fuzz boxes maybe thats not even that bad but with other clean effects like chorus boxes I think there's definitely a difference. Guitars usually don't go down to 10 hz but a low e is about 82 Hz.

What interests me is if you really can hear the difference. I need to build 2 chorus pedals or compressors with different caps and let my ears decide if I hear any major sound degradation