Tone Capacitor

[32soundz]

Guys thanks for all the info, I guess I should experiment a bit myself, here's the current cap.

[Teleterr]

Originally Posted by Narcoleptigon

Generally, yes. Cap value doesn't matter with the knob above ~4 on an average audio taper pot. However, different types and/or voltage rated caps have different reactances, which means they have different AC resistance values at various frequencies. Therefore, there should be a slightly different frequency envelope, even with the knob at 10. I would suppose that the more resistance is in front of a cap, the less noticeable the difference will be. I don't know about cap types, but higher voltage rated caps might have a more significant variance in reactance? Still, the test on this page shows there isn't any difference to speak of: http://www.aqdi.com/tonecap.htm

It's probably worth checking out a few types. To do an accurate comparison, you'd need to actually measure the capacitance for each cap type with an accurate meter, and then use the ones with very closely matched values, within like 5%.

You could also soften the roll-off slope above the resonance of any cap by adding like a 20-50k resister in parallel with it, but in series with the pot. The total resistance on the circuit would be slightly higher, but not really enough to notice. It seems like overkill to me, but it might be fun to try out.

Why do say the cap value doesn't matter ABOVE 4? Am I missunderstanding? As you cut the tone just a little, different caps sound different. Or does it sound the same to you? sjtalon's description is how it is to my ears too.

[Rob DiStefano]

caps in passive guitar audio circuits shunt treble tone to ground. pots do too. you can't add treble to a passive guitar circuit, but you can remove those devices that suck it away. the more crap you stick into a passive circuit - even just more or longer hookup wire - the more there will a component interaction that can affect tone. sometimes the best "tone pot" is the volume pot. in passive audio circuits, tone is never effected, it's affected.

the only things that matter for caps in passive audio circuits are value, tolerance and build. period. put yer pip and bumble bee caps in amplifier circuits, please.

with that in mind, i prefer to use no-load tone pots and a cap value that yields a wider sweep of mud tone, such as a .022uf, but there are other values to experiment with since all guitar circuits are somewhat different, particularly as they are driven by different engines (pups).

[Narcoleptigon]

Originally Posted by Teleterr

Why do say the cap value doesn't matter ABOVE 4? Am I missunderstanding? As you cut the tone just a little, different caps sound different. Or does it sound the same to you? sjtalon's description is how it is to my ears too.

If you are saying that from say 10-4 on and audio taper tone knob, a different cap value sounds different on the same pickup/guitar/cable/amp, I don't know what else to say. With the tone above ~4, the circuit resonance is determined by the cable (and any other capacitance in the circuit). If caps sound slightly different on 10, then they will sound different across the entire knob sweep, and that should be due to reactance, or some hither to unknown factor. You might try just substituting a cap with a piece of wire. Then, compare the tone from 10-4 with that of a cap. They should sound very similar until you get to ~4. Either way, if you prefer the tone of a certain cap, use it. Keep in mind, it will sound different on another pickup and/or when pickups are combined. That's a good reason to use different caps for each pickup. Usually, you'd use a higher value cap on the neck.

[Derek Kiernan]

Capacitors of equal capacitance in guitar circuits will sound identical to each other. Narcoleptigon, I don't know where you're getting all these other variables. I'd be impressed if anyone found capacitors with voltage ratings that could in any perceptible way change performance. I'm not sure there are any on the market! I have no idea why you would recommend a cap with a 100V rating for a circuit that deals in mV. Same with inductance. If you think you can hear any difference due to inductance with electronics that are measured in pico-Henries, it's not the sound.

[Narcoleptigon]

Derek, if you read back, you'll see that I said it's the reactance that might account for slight tonal differences in cap types. Not all types and/or voltage rated caps have the same reactance. Resistance leakage (faulty caps) can also be a factor. I also said that the differences could be very subtle -- very possibly outweighed by the variance in the actual capacitance between caps. I also provided this link that shows there actually isn't any measurable difference among caps measured to be the same: http://www.aqdi.com/tonecap.htm
It's a much more thorough and scientific test than the one done by the guy in this video:
http://www.tdpri.com/forum/just-pick...ml#post4135367

Still, many people claim they hear a difference. I've been looking into it and have had discussions with engineers, even several Ph D's to find possible reasons for what people claim. I definately don't suggest spending a lot of money on NOS caps, especially when they could have significantly changed value over time, but higher voltage caps can be had so cheaply, it's really not an issue to try them.

[Rob DiStefano]

Originally Posted by Narcoleptigon

Derek, if you read back, you'll see that I said it's the reactance that might account for slight tonal differences in cap types. Not all types and/or voltage rated caps have the same reactance. Resistance leakage (faulty caps) can also be a factor. I also said that the differences could be very subtle -- very possibly outweighed by the variance in the actual capacitance between caps. I also provided this link that shows there actually isn't any measurable difference among caps measured to be the same: http://www.aqdi.com/tonecap.htm
It's a much more thorough and scientific test than the one done by the guy in this video:
http://www.tdpri.com/forum/just-pick...ml#post4135367

Still, many people claim they hear a difference. I've been looking into it and have had discussions with engineers, even several Ph D's to find possible reasons for what people claim. I definately don't suggest spending a lot of money on NOS caps, especially when they could have significantly changed value over time, but higher voltage caps can be had so cheaply, it's really not an issue to try them.

some of the thinking about tone caps in passive guitar/bass audio circuits is fraught with total nonsense. those who THINK they hear differences in capacitor TYPES are fooling themselves and propagating more guitar myth on a gullible public audience. all of this is just silliness. when you can consistently pick out each of six different cap types inserted and played with in one specific guitar, then make yer post. 'til you show and prove your empirical data/testing, stop the hearsay nonsense please.

[Narcoleptigon]

Rob, First, I find it a little hard to believe that you are saying this. I thought you believed they sound different. I don't understand why I am suddenly the brunt of your statement, especially considering all the absolute ill-informed statements and downright false supposition made by several other members in this thread. What gives, man? Second, I'm not the one propagating the myth. I usually argue against those who claim they hear a difference. The test made in the link I presented backs the argument that there is no difference. That's the main reason I posted it. Third, reactance is not hearsay. Whether anyone can actually hear it's effects is another matter. I don't have an opinion on that. I do know that I can hear certain eq changes down to ~1/10th of a dB, depending on the signal content. As far as I'm concerned, the best test I've seen is in the link I posted. The conclusion is that there isn't a difference. Basically, don't kill the messenger.

Still, I gotta say that I don't get why people seem to hear a difference with the tone at 10? If the cap value doesn't matter, why do they hear a difference? Maybe there is something we haven't considered, like resistance leakage, reactance, noise signature, or who knows? I have no opinion on the matter accept that whatever effects they might cause are near impossible to consistently recreate and really too insignificant to be concerned with. That has always been my stance on the matter. In a related matter, it's generally accepted that humans can't perceive midi timing variations below 5ms. Some drummers claim otherwise. Who am I to argue?

[Rob DiStefano]

i believe, no - i know that caps in passive guitar audio circuits eat treble and that all that matters with caps is their value, tolerance, and build. the build part hasta do with durability only. that's about it. all the voodoo mojo talk about pip and beebee caps is just that: talk. that's about it. it's that simple. if any normal human hears differences in cap types, show me. can you?

[Narcoleptigon]

You didn't address the things I brought up, Rob. Are you saying that reactance and resistance leakage have no perceivable effect? Maybe they don't. I'm not attempting to prove that they do. I'm just considering possibilities. Personally, I don't care one way, or another. As I said, the test I linked to is good enough for me.

One thing I do know is that analog filters do not have completely smooth slopes. There is some subtle wavering along the slope, particularly along the low end cut off in a HP filter. Perhaps it varies with different cap voltage levels (mass), or materials? That may account for some of the differences people hear? I don't know, and I'm not prepared to make a definitive answer one way, or another. You smell me?

[Derek Kiernan]

We are dealing with an AC circuit, so we are always dealing in capacitive reactance and inductive reactance, not capacitance and inductance themselves.

j = -j[1/(2πfC)]

[Narcoleptigon]

And what of reluctance, sir?

I really don't know that much about it, and don't quite follow the equation. Even so, would it provide a way to determine which cap sounds better than another? I just don't think it's all that important. I use cheap ceramic ones and don't generally even roll my tone below ~5, anyway.

[Derek Kiernan]

Without understanding the equation, you really can't say anything about capacitive reactance. You're mystifying physics terminology in a way that's needless and unhelpful. If you're interested in physics, this is widely covered and understood when dealing with electronics and can be found in most textbooks. Laypeople (most musicians!) aren't helped by this, so it's not useful to explain here, but explanations are easy to find for your personal knowledge if you feel the drive to understand electronics, and necessary if you use such terms to explain yourself or question other people's understanding.

[sjtalon]

and on and on it goes, it really is comical, put yer boots on boys, it's gettin' deep

love it

[Narcoleptigon]

Personally, I'm really not interested in stroking my ego by entering in some heated and relatively insignificant debate. I just thought I might share a view point I have yet to see offered on this topic.

No, Derek. That's your interpretation. Anyone can say that reactance exists, as far as a potential function can be proven to exist. I'm actually just offering possible explanations to consider for why different caps might sound different. I make no claim to the actual solution to the standing "quandary". Musicians might begin to understand that they can't make claims that said cap type sounds "better" than another precisely because we don't fully understand what is happening? Furthermore, I have yet to see a link to a more comprehensive comparison of caps than the link I have provided. I absolutely defer to the experts on this, and have proven so in my posts. Have I not?

If you have a specific complaint, rather than just continue to devalue my entire philosophy, approach and methodology, please address it. I'm sorry if you can't see the difference. Clearly, I've already stated several times that I don't claim know the answer. So, whether I understand the symbols in a mathematical equation is irrelevant in this case. In any case, debate for debates sake is all well and good, but it bears little resemblance to how real problems are solved in the real world. A mathematical equation doesn't necessarily solve the real world equation. Once again, I'd suggest not wasting money on expensive caps. I don't see the problem.

[Derek Kiernan]

I'm not devaluing any philosophy. If you understood what capacitive reactance is and what its relevance is to an AC circuit, you wouldn't conjecture on it as a possible hidden variable, because it is plainly what we are dealing with in AC from the start if you are familiar with the terminology. If you are not, it is not helpful to use it. There is no interpretation. You can't conjecture about words and get upset when they already mean something particular, or defensively suggest you're not trying to prove anything and don't care one way or another but demand it of others. It's unfair to question people like Rob in misleading ways. There is no debate, and there's no ego in physics :D Physics is physics, not interpretation, and physics terminology mean something specific. If you're curious, a great book to read is Modern Physics for Scientists and Engineers by Lawrence Lerner. It's available used online for rather low prices and is great to work through at your own pace if you are passionate about the topic.

[Narcoleptigon]

OK, DK. The "interpretation" I allude to is about my intentions, not about the laws of physics. Are you saying that reactance has no effect on the resolution of the slope, or even just the gain, or shape of the Q with the knob at 10? That's fine. Good to know. Seriously, I really don't care that much about such insignificant and irreproducible subtleties, and that's a fact. I'm just not prepared to devalue somebody's experience based on mathematical calculations. I'm trying to find a reason to somehow validate the experience. Maybe I shouldn't bother?

[Derek Kiernan]

The point is that people should measure their capacitors' capacitance and know their values when comparing them to others when using a specific pickup, because the capacitor doesn't have any other value that affects performance. It's useless to try to complicate this, which is fairly easy for the people concerned about it here, by employing concepts in physics you don't understand and are upset by when you are told the meaning. X is reactance, the subscript denoting capacitive, the other variables corresponding with the imaginary component, frequency and capacitance. Again, you can find this equation in many places. You can't conjecture on what "reactance might be" or what it "might do" just because you don't have a good explanation of what you think you hear.

Also, you often say you're only suggesting or inquiring, but when you write a sentence like "not all types and/or voltage rated caps have the same reactance," you're making objective, falsifiable claims. If you don't understand the significance of the concepts or the numbers, you're not situated to say anything about it.

[Narcoleptigon]

Unless it is proven otherwise, it would be more accurate for me to state that different types/voltages may have different reactance values. If it has been proven that they don't, I definitely stand corrected. I must have interpreted otherwise from the writings of an engineer I corresponded with. At least we know that resistance leakage can be a factor, especially concerning oil and paper caps. There is a common sense element to that conclusion. There may be other factors that alter resonance, like those I have previously mentioned. I may look into it further, but I find it so insignificant compared to the whole "equation" -- not to mention the human "equation".

[Derek Kiernan]

Nothing can be proven to you because you would already have to know the language, which means you would already have to know the concepts and the significance of the relevant variables in context if you decided to independently investigate it. It's a really silly game to say they "may" have different reactance values which "may" affect something electronically that you "may" hear if reactance "could" mean something having to do with anything you "may" be thinking of.