Which caps are best?

[lumgimfong]

Paper-in-oil
Ceramic
Orange drop
Poly pro
Polymer
Bumblebee

So many choices out there and I have no idea what materials make what difference. Anyone got the lowdown?

[jps]

Paper-in-oil
Ceramic
Orange drop
Poly pro
Polymer
Bumblebee

So many choices out there and I have no idea what materials make what difference. Anyone got the lowdown?

For what purposes? IF for a tone control cap, it makes no difference as it is not in the signal path. Don't let the snake-oil guys convince you differently.

[aceonbass]

IF for a tone control cap, it makes no difference as it is not in the signal path. Don't let the snake-oil guys convince you differently.

If that were actually true, I'd be using 15 cent ceramic caps from Radio Shack, and so would John Hall. While it is very difficult to tell the difference between the basic types of tone caps, some are definitely not as good as others, and some are noticeably better than others.

[lumgimfong]

If the values are the same, can you hear a diff in the different types?

There seem to be two schools of thought:

1. Its all snake oil http://zerocapcable.com/wordpress/?page_id=224

2. Dramatic changes in tone depending on which brand/type you use. https://www.premierguitar.com/articles/ ... -part-ii-1

[jps]

I very much comes down to where it is used: in the power supply, the audio path, itself, or in areas where audio does not flow to following stages, ie, the signal from a guitar pickup to its output jack where the main audio is carried from the pickup to the output jack but part of the audio is shunted to ground as in the case of a tone control pot and capacitor. That signal is bleeding off the highs to ground via a capacitor so there is no detrimental effects of the capacitor as that signal will not be heard (being grounded out). Somewhere there is as treatise on this by Rick Turner from some time ago. A quality cap is what one would want to use but there is so much snake oil voodoo shenanigans surrounding this to enable high end cap companies to prowl on the unsuspecting. Now in circuits where the audio passes through the cap and goes on the final output (an amplifier, recording console. etc.,those types of caps should be of the highest quality to not anything detrimental to the audio signal unless such is desired, an example being the vintage tone circuit on Rick basses where the cap is in line with the pickup, rolling down the bass and low mids from the audio signal In that application you want the highest quality caps that are reasonably priced for the job on hand.

[cjj]

I always hate to get involved in this sort of discussion, but...

A cap is a cap is a cap. Or is it? Well, in reality, no, all caps are not created equal and as has been stated, how well it performs depends on what you are doing with it.

In its basic form (the ideal cap), a capacitor has "capacitance." In the real world, all caps have capacitance and also have resistance and inductance. The resistance is in the leads as well as the internal materials used to form the cap. Different dielectric materials (what separated the plates) have different leakage resistance, different plate materials (e.g., foil vs. metal film deposition) have different resistance too.

Same goes for inductance, it's in the leads and in the internals. Stacked flat metallic plates (generally in ceramic caps) have less inductance than spiral wound layers of foil.

Different dielectric materials perform differently depending on the frequency as well. This means that the capacitance changes with frequency. Some dielectric materials change their properties under mechanical stress (ceramic caps are knows for having "microphonics").

So what does all of this mean? Well, different caps WILL perform differently under the same circumstances. Can you hear the difference? Maybe. Depending on where it's used, the type (or even manufacturer) might make a difference. There's certainly a LOT of snake oil filled caps out there and many folks who spend the extra to buy magic caps will definitely believe they sound better. Some, I'm certain, if given a true, double blind evaluation probably wouldn't be able to tell.

So, what to do? In general, unless you really know what you're doing, it's best to stick to the types that people generally use for the application at hand. Even then, caps aren't really all that expensive so try a few different caps yourself and see if you can hear a difference...

[Isaac]

If the values are the same, can you hear a diff in the different types?

There seem to be two schools of thought:

1. Its all snake oil http://zerocapcable.com/wordpress/?page_id=224

2. Dramatic changes in tone depending on which brand/type you use. https://www.premierguitar.com/articles/ ... -part-ii-1

I loved the zerocapable.com article. I come from an engineering background (I am a retired Navy nuclear electronics technician) and I strongly tend to agree with good engineering practice. The premierguitar.com article makes a lot of assertions, but doesn't back any of them up.

One reason to use perceived higher quality caps is just that: the perception of higher quality. If people think it sounds better, it almost always does, to them, even if there is no measurable difference and no one can tell the difference in a blind test. Another reason to use higher quality caps is the tolerance factor. Ceramic caps tend to have a high tolerance, so you can't really be sure what value cap you're putting in. That leads to a lot of variation between supposedly identical instruments.

There are applications in which the type of cap makes a substantial difference. The zerocapable article mentions some. Another is speaker crossover networks. Because of the low impedances, large caps are required. In the past, this usually meant electrolytic caps, but they have a problem in this application. They tend to have high inductance, which messes with the impedance curve. At some frequency, the electrolytic cap becomes resistive, then inductive, its impedance actually going up with frequency rather than down, as we expect from caps. Fortunately, the zerocapable article graphs showed no sign of this effect out to 20KHz for any of the caps tested. They didn't specifically test any electrolytics, but many of the caps tested were of unknown type. Based on the results, I assume that none were electrolytics. Makes sense, as electrolytics are polarized, which is not a desirable trait in a tone cap application.

[soundmasterg]

When you talk about any part in a guitar or an amp, the only way to really test it is to combine the electronic tests with actual listening tests, since we are talking about something that produces sound. With the electronic tests, you can find out which material used or style of construction gets you closer to a perfect cap, but these electronic tests can't measure everything that a human being hears. They can capture the frequency range that we hear but not all of the nuance....there is still a lot that is not understood about our hearing. The best listening test to perform is a double blind test, where the people who are judging have no idea what caps are being switched in or out. The other important thing is that each cap that is being used must be the same exact value so that the only difference you are listening for is the dialectric differences between the caps and if that affects the sound. In a tone cap position in a guitar or bass where the cap is shorting AC signal to ground, any difference will be much less noticeable than in a coupling cap between stages in a guitar amp. Since we all hear differently, then it is hard to say that something someone else is hearing is or isn't valid, which is why some people tend to go to defining stuff with measurements from test equipment. The thing is, both methods are legitimate and must be used in combination.

I have a BSEE and am a musician. In school you are taught about how a perfect capacitor performs in a circuit, and then how that relates to real ones. When real ones are included the math gets much more difficult, so they don't spend too much time on it in comparison. No one hears with math though so that is something to consider. Everyone (engineers designing circuits) these days uses computer simulators to determine the parts to use and then builds prototypes to see if the electrical performance matches what the sim says. If you are talking about audio applications, you would hope that the engineers that are designing these things are also musicians or recording engineers or someone who can appreciate the differences in sounds that are sometimes very subtle and influenced by the part chosen, but sadly that isn't the case. A piece of test equipment can't tell you what an amp feels like when you play a guitar through it or dig in harder or softer, but a musician can, and a good one can tell you why that matters.

Orange Drop and Bumblebee are particular brands of caps, and within those, there are different dialectrics that have been and are used. The Orange Drops can be film and foil or metallized in their style of construction, and can be polyester, polypropylene, and perhaps a couple others. The Bumblebees can be paper and polyester, or paper in oil. Every Bumblebee cap I have ever seen has leaked DC. This would be a big problem in a guitar amp application but in a guitar or bass in a tone control circuit it wouldn't matter since those only see AC in that circuit. Since these caps had paper in them, that is a problem, especially after so many years. Paper is hydroscopic, which means it attracts water. The caps also tend to drift in value over the years. I would personally stay away from vintage Bumblebee caps, vintage Astron caps, vintage Black Cat caps, and many other similar types because of the drifting and moisture attraction issues. Many unscrupulous amp techs will also take caps out of amps, tell the customer they failed, then sell them on ebay for huge prices, and they never even check the cap to see if it is still within spec. Likely because they don't have the equipment to do so. Just using the cap check function on a DMM isn't adequate to get a full picture of the cap. Another thing is the new "Bumblebee" caps are just a modern cap in a vintage looking "Bumblebee" case. Don't buy into the hype on those.

To summarize, there may be differences but when you make sure each part choice is the same exact value, then you will find there isn't much difference. There will be more difference by a long shot by changing your strings, or the speaker, or the tubes in your amp than there are from the cap used on a tone control in a guitar. Some of the best vintage guitars have used ceramic caps, paper in oil caps, paper and polyester, etc. Use whatever you think sounds the best...caps are cheap and its your labor to change the caps so it comes down to how you value your time.

Greg

[lumgimfong]

So I guess I'll just have to try different .022 caps and see what I like best. That will be fun! Hopefully not too expensive though! I think I will stay away from vintage as I keep reading that the values drift over the years. It will be interesting to see if I'll be able to hear an easily noticeable difference.

[soundmasterg]

So I guess I'll just have to try different .022 caps and see what I like best. That will be fun! Hopefully not too expensive though! I think I will stay away from vintage as I keep reading that the values drift over the years. It will be interesting to see if I'll be able to hear an easily noticeable difference.

You will hear noticeable differences if the caps that you swap in are not the exact same value as each other. In order for your swap test to be accurate, each cap has to be measured with a capacitance meter and each cap must be within probably a 1% or less deviation from each other in the value shown on the meter, or you will possibly hear a difference. When you buy the caps they are all listed as a 0.022uF cap for example, but they all have a tolerance and that 0.022uF cap could be a 0.02178uF or a 0.02222uF cap, or anywhere in between for a 1% tolerance part. Caps can come in higher tolerances too, 5%, 10%, 20%, 50%, etc. Usually the smaller cap values are no worse than a 10% tolerance but you need to pay attention to the exact values the caps test out as because if the value is different, then the sound will be different. If you don't have a DMM with a capacitance check on it to check the caps, then your experiment isn't really meaningful.

Another thing to consider is that the ear has a very short memory, and if you are swapping the parts in by soldering one at a time, or using test leads, then you will have to go back and forth between them many times and you will think you hear a difference, but if you had caps soldered up on a switch with someone else flipping the switch as you play, then you wouldn't hear as much difference. It is a trick that our brains play on us.

Greg