Wow, cap type makes a difference

[eddie_bowers]

I have a pedal design I have been making several of (an overdrive) that sounds real good.
I was using components I had on hand, so when I ran out of a particular cap, I ordered another one with a smaller footprint, but the same value and same type (Polyester Film).
When testing the new boxes, they just didn't sound as sweet, so I A/B compared with one with the old cap.  The old one with the original cap sounded better.
I then dug out some more of those original caps and replace them on the "bad" one.  It then sounded good!

What the heck?   Now i'm afriad to change anything even slightly.

The original cap:
http://www.mouser.com/ProductDetail/Panasonic/ECQ-V1J224JM/?qs=Y%2fBAFGi0CNopD%252bRk6GBd7w%3d%3d
The replacement that sounded bad:
http://www.mouser.com/ProductDetail/EPCOS/B32529C224K/?qs=sGAEpiMZZMvOcEq4GH1AAp5e5k2EDOoww1rNZVJBJbQ%3d

The tolerance is higher on the "bad" one, but on a cap meter it looks as close as the other ones.

[Scruffie]

The originals had tighter tollerances so were closer to the specified value, i'd bet that was why it sounded better, not the material... but i'm not opening that can of worms with anyone.

[zombiwoof]

Yeah, this has been debated to death in the past, but I think it depends on where the cap is in the circuit, and what it's function is.  Some people have observed that in some circuits, a certain type cap can make the sound "grittier" or "smoother" on say a distortion or OD type pedal.  Some guys like to use cheap ceramic caps in certain vintage pedal clone designs because it seems it might get closer to the sound of the original pedal in some cases, even though most people would go for a film cap routinely in their pedals.

I'd say if it sounds better to you to use a certain type of cap, then go for it!  Many people will say it doesn't make a difference, but if it does to you then it's cool!.

Al

[ayayay!]

There's too many variables in the other components to definitively point to this one single cap in this one pedal, even if everything is down to 1% or less for tolerance.

What you need to do is:

a) swap the caps in both pedals with each other, and compare sounds.
b) use two of the same old caps in both pedals, and compare sounds.
c) use two of the same new caps in both pedals, and compare sounds.

It's not "pure" science to do it this way, but I've made two identical pedals before that sounded different from each other.  There's just too much subjectivity with other component tolerance.  

[DougH]

I've swapped cap types out on the breadboard and definitely heard differences. Differences that consistently pertained to a certain type and created similar effects in other circuits. With 9v pedal circuits, most of the time they have not been "make or break" differences AFAIC, but there have been a couple exceptions. With amps, the differences I hear are more dramatic. For example, I've been changing out the silver micas in the coupling cap and tone stack treble positions in my amps for high voltage ceramics, as I prefer their sound. They are smoother and less spikey, as micas are actually better caps and more "accurate" for lack of a better term. I have gotten consistent and similar results with two amps so far and am getting ready to "upgrade" a third.

In the end, just do and use what you are happy with. I see no reason to get into forum debates about this kind of stuff.

[eddie_bowers]

Thanks guys.  At least i'm not crazy.
This stuff can drive you nuts.  It makes me wonder about other designs I have dismissed and if small changes like that would have made them better.

[DougH]

Thanks guys.  At least i'm not crazy.
This stuff can drive you nuts.  It makes me wonder about other designs I have dismissed and if small changes like that would have made them better.

Wondering about going back and tweaking stuff can drive you nuts too. Been there and done that sort of thing.

What I've learned is- if you are happy with the sound you're getting, relax, play your guitar, enjoy life. 

[R.G.]

Thanks guys.  At least i'm not crazy.
This stuff can drive you nuts.  It makes me wonder about other designs I have dismissed and if small changes like that would have made them better

Back in circuits class, we sometimes had to compute the "sensitivity factor" of something to something else. For instance, if I change this resistor right... here...  how much does the voltage ... here... change? A sensitivity factor of one means that the measured point changes one for one with changes in the thing you're changing.

This is one way of describing what you're saying - would small changes in one thing make big changes in another? Sensitivity factors range all over the map from almost zero (Hey! I can change this all I want and nothing happens!) to very big (Wow! I just touched that thing and it went through the roof.)

In general, the type of insulation in a cap (mylar, paper, electrolytic, etc.) has only a very minor effect on audio tone. But changes in the value of the cap, even well within the +/- tolerance band, can be easily detectable by ear. This has been the basis of wildly overblown claims of this or that (generally very expensive) capacitor makes worlds of difference in tone. This has happened so much in the hifi world that it's almost a flashing light indicating chicanery.

Before you can realistically state that X KIND of cap makes a big difference you have to eliminate other things that it could be. Naturally the snake oil salesmen viciously attack any unbiased testing. They like the money too much. And human psychoacoustic effects have a way of getting in the way.

So be very careful about generalizing a few capacitor changes into "this kind of cap is always better". It might save you a lot of money over time.

[Hides-His-Eyes]

I use ceramic caps for allsorts of things, because they're cheap. I figure: everything about the tubescreamer 30 odd years ago was all about how to build things as cheaply as possible: so in 30 years time, all my builds will have vintage mojo!

[Paul Marossy]

In general, the type of insulation in a cap (mylar, paper, electrolytic, etc.) has only a very minor effect on audio tone. But changes in the value of the cap, even well within the +/- tolerance band, can be easily detectable by ear. This has been the basis of wildly overblown claims of this or that (generally very expensive) capacitor makes worlds of difference in tone. This has happened so much in the hifi world that it's almost a flashing light indicating chicanery.

Yeah, and these companies selling the caps are laughing all the way to the bank. I put this in the same category as Monster Cable products for guitar use. In my mind, the exorbitant price tag of their guitar related products is not justified.

[petemoore]

  I use *chicklets or something for stompboxes, I tried the mica-silver-precision resistors/caps route for a few builds, FF probably not the best choice for detecting capacitor minutea. Some old effects use the brown ticks...I did notice something about them when comparing to the *greenies...perhaps the tone or the glossy color.

[Greg_G]

In this instance, the 2 caps used are of the SAME construction... both are Metallized Polyester !
So.. the only difference is the manufacturer.
All the replies refer to different cap types.

Sorry, but for me I have a lot of trouble believing that 2 modern caps of the same type and value will sound different.

[Gus]

It all depends.  At 9VDC the dielectric stress is lower at higher voltage difference the dielectric stress is higher.
Some materials are microphonic.
As posted before you do need to have the same value to do a comparison, so you need to measure the caps with a good cap meter
Cyril Bateman had a few very good PDFs on capacitor distortion on the web.

[StereoKills]

Sorry, but for me I have a lot of trouble believing that 2 modern caps of the same type and value will sound different.

And here lies the key. Often, the tolerances for caps are 10%, or even as high as 20% in some cases. So if you have two 500nf caps with a 20% tolerance rating, one could be 400nf and the other could be 600nf and both would still be in spec! In the right place in a circuit, that difference definitely has the potential to have an audible effect.

[DougH]

This has been the basis of wildly overblown claims of this or that (generally very expensive) capacitor makes worlds of difference in tone.

What's funny about that is I prefer the sound of the cheaper caps in my amps. But my empirical experience is similar to the carbon-comp resistor story- the differences are more apparent at higher voltage, and a lot depends on the position in the circuit too.

[Greg_G]

Sorry, but for me I have a lot of trouble believing that 2 modern caps of the same type and value will sound different.

And here lies the key. Often, the tolerances for caps are 10%, or even as high as 20% in some cases. So if you have two 500nf caps with a 20% tolerance rating, one could be 400nf and the other could be 600nf and both would still be in spec! In the right place in a circuit, that difference definitely has the potential to have an audible effect.

That's why I specified the same value..  
I meant tested.. and the SAME value... not what it's marked as.

The OP did say he used a meter on them.

[Toney]

I am down with this too.
I hear tonal differences that are quite obvious to me with same value different manufacturer caps.
Eventually reading all the traditional replies regarding values differences with manufacturers etc, I tried a couple of very simple 1 or 2  cap builds with a variety of Mylar caps matched the best I could find with my cap meter. No significant value difference but audible tonal change.

I liked cheap Dick Smith "greenie" and Panasonic stacked types the best so I have gone with those.
Really don't care if people say its impossible because I can hear it.

[R.G.]

I hear tonal differences that are quite obvious to me with same value different manufacturer caps.
Eventually reading all the traditional replies regarding values differences with manufacturers etc, I tried a couple of very simple 1 or 2  cap builds with a variety of Mylar caps matched the best I could find with my cap meter. No significant value difference but audible tonal change.
...
Really don't care if people say its impossible because I can hear it.

I fully, completely believe you. You absolutely, positively DO hear it.

But have you ever set up a test where neither you nor the person changing the caps didn't know which one you were listening to at any moment? 

[Paul Marossy]

I hear tonal differences that are quite obvious to me with same value different manufacturer caps.
Eventually reading all the traditional replies regarding values differences with manufacturers etc, I tried a couple of very simple 1 or 2  cap builds with a variety of Mylar caps matched the best I could find with my cap meter. No significant value difference but audible tonal change.
...
Really don't care if people say its impossible because I can hear it.

I fully, completely believe you. You absolutely, positively DO hear it.

But have you ever set up a test where neither you nor the person changing the caps didn't know which one you were listening to at any moment? 

That's the real test right there. 

[petemoore]

  that's one real test...
  Considering that even if all the components like pots are measured/accurate and set the exact same...if it can be proved to sound different, it Is different...
  To find whether 'better' better fits the days words, would be best suited to the slightly longer term test of try this one blind but let somebody tweek it for you, try the other without knowing which one is which...tweek the knobs at all times to see what you prefer.
  Then, if it turns out that it's still possible to tell them apart, I offer challenge to describe the trade-offs...ie which one is 'better for this' regards.
  I've read some convincing threads and advertisements about guitar control cavity capacitors, as well as amplifier capacitor preferences, I see no reason to leave stompboxes out of the realm of cap-battles.