Great Article On Guitar Tone Capacitors

I was browsing around the Squire 51 Modders Forum and found this link that someone posted to an article in Premier Guitar about tone caps. Very interesting article:

http://www.premierguitar.com/Magazine/Issue/2008/Mar/Auditioning_Tone_Capacitors.aspx

Excellent resource Blooz, thanks for posting it!

Thanks Blooz! That is some good stuff. I kind of like the idea of having one cap on half of a pot and another on the other half. Might be a good experiment. I am sure I would settle on one or the other but a good way to try it out.

M

Wow, what a great article. Caps always confused me when it comes to voltage vs sound, the easy to follow article really cleared a few things up.

nice find

Good 'un, BC! I wished he'd gotten into different types of caps, such as PET flim vs. PS flim vs. ceramic, etc., but maybe that's gonna be in next month's issue....

I think the author plans to get into differences in pot construction and brands in the next installment of this article. I think this was just part 1 of 3.

I might have to check into getting a subscription to this magazine. It sounds like a mag for those of us who always want to know the intricate details. At $14.95 a year plus two bonus months added, it sounds like it might be something worth getting. They do feature articles like this one regularly on the website too, apparently.

Cool concept...a modders magazine. :AOK:

I've been using different value caps for the tone controls on both my 1-V, 2-T and 2-V, 2-T guitars for a while now, but I've never tried values like those listed in the article. I'll have to go home tonight and check my cap inventory for some of the values used in the article.

Cool article! I know nothing of these things, so it is good to know a little. I tend to just dime both tone knobs and go.

I almost forgot about this article...

Part Deux...

http://www.premierguitar.com/Magazine/Issue/2008/Apr/Auditioning_Tone_Capacitors_Part_II.aspx

I just recently ordered a moderate quantity of Mil. Spec. NOS Sprague Vitamin Q paper in oil caps, and some other Goodall NOS Vitamin Q type made to the exact Mil. Spec. The sizes are .010mf, .022mf, & .047mf.



For those who aren't familiar with these caps, they are the Mil. Spec., hermetically sealed, triple insulated version of Sprague's Black Beauty/Bumblee capacitors (although they look different). Since all the NOS caps of this type are from the 50's-60's, the Mil. Spec. Vitamin Q's have a slight advantage in that due to their hermetic seal, they don't leak like the more famous Black Beauty/Bumblee caps sometimes do. Capacitors in this family are the ones that are prized by Les Paul owners for producing the legendary "vintage LP tone." The discussions on the Les Paul Forums are a testament to the popularity of these caps.

Anyway, I'll be gone on a much needed two week vacation with Mrs. Bloozcat starting this Saturday. But when I come back, I plan to begin experimenting with these caps in my Agile LP (humbuckers), my Agile DC LP w/P-90's, and my Ibanez AS-73 semi-hollow (humbuckers). I'll probably try them out in a couple of Strats too. Should be interesting...

A Great article and info Bloozcat...Thank you for posting it!!:AOK:

I'm sorry but he had me interested until he said thigs like..

A cap with a higher voltage rating does not sound different from the same cap with a lower voltage rating.

and then..

. If you want to use the vintage caps, make sure that you use vintage cloth wire inside your guitar and the Gibson fifties vintage wiring, otherwise you will not fully experience the tones from these caps.

So, he's suggesting that two capacitors with different construction (obviously a difference in construction is required to get a higher/lower voltage rating) sound the same, but a cloth covered piece of wire sounds different to wire with a modern covering? Debunk one myth and perpetuate another....

It was cool going over all the types of caps though, In my previous life as an electronic engineer and service guy I think I've seen all those types of caps in one type of equipment or another, I wish I'd held on to a lot of the old ones now, cause it would be fun to try them in my stomp box's...

Ch0jin said:

I'm sorry but he had me interested until he said thigs like..

A cap with a higher voltage rating does not sound different from the same cap with a lower voltage rating.

and then..

. If you want to use the vintage caps, make sure that you use vintage cloth wire inside your guitar and the Gibson fifties vintage wiring, otherwise you will not fully experience the tones from these caps.

So, he's suggesting that two capacitors with different construction (obviously a difference in construction is required to get a higher/lower voltage rating) sound the same, but a cloth covered piece of wire sounds different to wire with a modern covering? Debunk one myth and perpetuate another....

It was cool going over all the types of caps though, In my previous life as an electronic engineer and service guy I think I've seen all those types of caps in one type of equipment or another, I wish I'd held on to a lot of the old ones now, cause it would be fun to try them in my stomp box's...

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First of all, here's the link to part III that brings the caps together with the wiring:
http://www.premierguitar.com/Magazin...ire_it_Up.aspx

Over the last several years, I've been following and studying guitar circuit wiring and how the various components affect tone. There is a preponderance of evidence out there that confirms many of the things that have been said in these (3) articles, and many others like them. My area of interest is very specific, and I don't claim to have vast knowledge accross the broader spectrum of electronics. While the results published in articles such as these might seem anecdotal in the broader sense of electronics, they offer imperical evidence that is very specific to this one area of electronics - guitar circuits.

As to the wiring: It's not an issue of the exact cloth covered wiring, but one of quality wiring. As I'm sure you're well aware given your background, Ch0jin, cheap wiring can often be responsible for an increase in capacitance, which in turn, can attenuate the high frequencies in a guitar circuit. BTW: Where did you see vintage cloth covered wire mentioned in this article? I went back through both parts and didn't see that exact reference. Maybe I missed it somewhere. I have seen it many times in other articles and discussions, as on the Les Paul Forum, though.

As to the using the vintage Gibson 50's wiring, there is sound reasoning for doing so that does translate into a tonal difference. I know this not only from having read it many, many times, but also from using this wiring scheme myself (see Part III, and the link to singlecoil.com).

From Part III of this series:

But what about losing signal volume in the wire? Remember, we said that these cords are feeding a high resistance; even the cheapest, crummiest, tiny-gauge copper wire you can find is only going to add a few ohms of resistance over a run of 100 feet or less. In practical terms, there is no difference between a few ohms of resistance and zero resistance when you are feeding an amplifier with an input impedance that is many thousands of ohms. But that extra-cheap wire is going to be unsuitable for other reasons – it will probably have very high capacitance, bleeding off your high frequencies to ground.

As to the caps: He was not suggesting that two caps of different voltages and different construction, would produce the same results. He's saying that two caps with the same construction and different voltages will sound the same. The different voltage ratings do not affect the tone in a guitar circuit. There have been many experiments done by modders and specialty shops that sell guitar electrical components, and they have shown that there is no difference in caps of identical construction/specs, but differing voltages. RS Guitar Specialties actually has a box that has many different caps in it that can be hooked up to a guitars circuit expressly for this purpose. They've done blind tests that have confirmed their published results. Others have done similar experiments using simple alligator clips and varying caps wired into a guitar circuit.


Believe me, Ch0jin, I'm Mr. Skeptic when it comes to what I consider "questionable information." I always want a body of evidence before I'm ready to believe something to be true. Well, my skepticism has certainly been assuaged in this area after finding mounds of information that support the conclusions stated in these articles (and many others). Of course, seeing - and hearing - is believing. And all that is required for that is a little experimentation of one's own....

Here's another great link that was included in one of the above series of articles. There's some really great info here:
http://www.singlecoil.com/

Enjoy, everyone....:AOK:

A lot of this stuff is over my head but I just wanted to let you guys know that you can subscribe to Premier Guitar for Free for 1 year. I did. There's a link on their website. There are some articles in there that I can understand!

Hi Bloozecat, that’s a great post.

I agree that if two sections of wire (well lets just say the looms overall) exhibit differing capacitance (and resistance and inductance perhaps) over the spectrum of frequencies a guitar pickup can generate, then they could and likely would, sound different. I am one of those annoying people though that isn't happy to accept things without proof (likely a result of being an engineer who now works in marketing haha), so I thank you for pointing out that this has been proven. It's just up to me to do the research now so my mind can chew over the physics of it and be satiated.

Oh and regarding the article talking about cloth wire..

"If you want to use the vintage caps, make sure that you use vintage cloth wire inside your guitar and the Gibson fifties vintage wiring, otherwise you will not fully experience the tones from these caps."

...was a cut and paste from the article.

On caps though I guess I didn’t explain my point clearly enough.

I wasn't actually disputing that different voltage ratings of the same cap effect tone, I was suggesting that the difference in electrical characteristics between two capacitors with the same capacitance and differing voltage rating would be more significant than cloth covered wire Vs plastic covered wire, and potentially even more so that the difference between solid conductor and multi strand wire, so based on that reasoning I questioned the statement that wire makes a difference and voltage rating on caps does not.

As you point out, both these things have been proven so I am happy to accept the reality that looms make a difference and cap voltage doesn’t, but if you’ll indulge me for a few minutes, this is the basis of my scepticism. As they say on Mythbusters.. “Warning. Science Content”

You said “As to the caps: He was not suggesting that two caps of different voltages and different construction, would produce the same results. He's saying that two caps with the same construction and different voltages will sound the same.”

I’m saying that two caps of the same type and capacitance and different voltage have different construction and that was the bit of popcorn stuck in my teeth (so to speak)

I’m sure we have all observed that a ceramic cap (for example) rated to 40V is physically smaller than one rated at 400V so I don’t think I need to quote references for that, but lets first look at Cap theory briefly. The maximum voltage rating and its capacitance determine the amount of energy a capacitor holds. The voltage rating increases with increasing dielectric strength and the thickness of the dielectric. The capacitance increases with the area of the plates and decreases with the thickness of the dielectric. Thus, the capacitance of a capacitor (C) is related to the plate area (A), plate separation distance (d) and permittivity (ε) of the dielectric.

OK moving on. If we take a 1uF capacitor rated at 10V there is definable ratio of C, A, d and e that results in its capacitance and voltage rating. To increase the voltage rating you need to increase the thickness of the dielectric to prevent arcing, and therefore your other values, most notably plate area will also have to change so the resulting capacitance remains the same, but now with a higher voltage rating. I think this proves my point that that two caps with the same capacitance and differing voltage ratings have different construction, so on to the last variable, ESR or Equivalent Series Resistance. ESR is the sum of in-phase AC resistance. It includes resistance of the dielectric, plate material, electrolytic solution, and terminal leads at a particular frequency. ESR acts like a resistor in series with a capacitor thus the name. It is accepted that as a result of the increased amount of “stuff” in a high voltage rated cap, the ESR is higher than its lower rated brother.

So in summary, the reason for my scepticism was based on the my hypothesis that there are a lot more electronic differences between caps of differing voltage ratings than there are between different types of wire so I found it hard to swallow that wiring looms make a difference, and voltage ratings don’t. From what you’ve said though it seems that in listening tests the science in my hypothesis doesn’t really back up the reality 

Anyway, I probably just got blacklisted for such a long post that has next to nothing to do guitars but maybe someone out there finds this interesting…

Why can`t I swallow all this "this capacitor sounds more punchy and transparent than that" talk?

Maybe my ears just ain`t good enough.

Ch0jin,

Great post...:AOK:

I sort of knew that you were speaking of capacitors in "wholistic" terms", to include the amount of energy (voltage) the capacitor holds. In that regard, there are the obvious differences in construction of the cap as you illustrated. Since we're only dealing with milli-volts in a guitar circuit, the capacitor really acts as nothing more than a pass filter for this specific purpose. Seems kind of silly in a way, that we might put a 600 volt capacitor in a guitar only to use it as a pass filter with no regard for the caps ability to store energy, but that's exactly what we're doing. It's sort of like buying a semi to go grocery shopping...it'll get you there, and bring back the groceries, but what a waste of capacity! But, we use what's available, and fortunately the voltage rating doesn't matter for our purposes.

The wire issue is really about the quality of the wire itself. In admonishing us to use vintage cloth covered wire in the circuit if we're to expect "vintage tone" as the author of the article does, he is only telling part of the story. Instead of explaining that the old style vintage wire is a better grade of wire than what comes in many new guitars (especially lower cost imports), he makes the wire sound as though it has some mystical quality to it (must be the amorphous "Mojo" we always hear about ). Of course, there's plenty of modern, mil spec wire that's at least as good, and in many cases better, than the old cloth covered stuff.

The greatest variable in all of this comes down to the human ear. A "what is, and what should never be", sort of conflict. What theory states, and can be proven mathematically, is often irrelevant to practical application when the variable (the human ear) is involved. The whole solid state vs. tube driven analog amplifier debate is another good illustration of this. Technically, the solid state amplifier is the superior circuit for producing sound. But, to the imperfect ear, it isn't. An engineer's conundrum, for certain...

BTW: I enjoyed your technical analysis, Ch0jin. I was raised by an engineer, the most exacting kind in fact - a quality control engineer. So, I come from a tradition of approaching every problem by analyzing everything that can possibly go wrong, before addressing how to make it right. My wife has often said to me, "you should have been an engineer, you think like one." Perhaps if my father hadn't been such a disagreeable individual, I might have considered it. As it was, following in my father's footsteps was not an appealing career path to me.

I've noticed the trend in recent years of engineers getting into marketing. It makes a lot of sense, really. It's a whole lot easier to train engineers in marketing, than it is to train those in marketing to be engineers. If you can't explain it, how in the world do you expect to sell it?

Iago said:

Why can`t I swallow all this "this capacitor sounds more punchy and transparent than that" talk?

Maybe my ears just ain`t good enough.

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It's hard to do by memory, Iago. What I mean is, we often replace caps (and other parts) in a random manner. If we don't like a particular tone, we change something, hoping for better. Trouble is, we don't compare the before and after in real time. There's just too much of a lapse between the time we hear the old component and the time we hear the new one installed. It's hard to remember exactly what the old part sounded like when there's this lapse. The differences are subtle when the tone is at full (10), with the more noticable differences occurring when the tone is rolled down.

That's why having a board like the one illustrated a couple of posts above, can be helpful in hearing the differences. You can switch caps very quickly while the previous tone is still in your head. The box with switch that RS uses, is even quicker. With the flick of a switch, you can change the cap in the circuit.

Another alternative is to record the tone of the guitar at various settings, change the cap out, and re-record the tone at the same settings. This is a lot more involved, but it would give the equivelent of a real time comparison.

All that said, I think the cap is still just one piece of the circuit puzzle. Getting the combination that delivers the tone is what matters. And that's what drives us as modders...

Bloozcat said:

All that said, I think the cap is still just one piece of the circuit puzzle. Getting the combination that delivers the tone is what matters. And that's what drives us as modders...

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I could not agree more. I can really see how easy it is to chase your own tail looking for a particular sound, I mean looking at my own gear for example almost everything in my chain is wildly vairable.

Guitar - less than a year old. I'm expecting the tone to change as it gets older and everything settles in.

Leads, for some reason all my leads are from different vendors..

Pedals, well I dont have a clean 9V supply built yet, so all my FX are on batteries so that varies the sound, particularly with drive fx.

2 of my pedals use germanium transistors that vary quite audibly with temperature.

Then all that goes into either of my tube amps and -they- vary in sound depending on how long they've warmed up for, particularly the homebrew.

Then there's my mood on top of all that.

It's a wonder anyone can accurately test the difference in tone one component makes!

I am posting this information for those who do not understand what a "Mil Spec" items is. Normally a Mil Spec controls the manufacturing of a a part or component beyond normal usage. The "specification " is controlled by the military or the Department of Defense. For example, during war time conditions a M-16 will normally be introduced to hot temperatures of 125 degrees (as in Iraq) or in cold temperatures of 120 degrees below zero (as in Antarctica). The military will tighten the requirements to test the rifle for temperatures to exceed 250+ degrees to 300 degrees below zero. This guarantees the rifle to survived all temperatures it could be subject to. These military specs is what drives the purchase price on many items used by the military. The engineering, development, testing and production of such items all cost money.

A better understanding is:

Defense standards evolved from the need to ensure proper performance of military equipment. For example, in World War II American screws and bolts did not fit British equipment. Defense standards provide many benefits, such as minimizing the number of types of ammunition, ensuring compatibility of tools, and ensuring quality during production of military equipment. This results, for example, in ammunition cases that can be opened without tools. The proliferation of standards had drawbacks, however. It was argued that the large number of standards, nearly 30,000 by 1990, imposed unnecessary restrictions, increased cost to contractors (and hence the DOD), and impeded the incorporation of the latest technology. Responding to increasing criticism, Secretary of Defense William Perry issued a memorandum in 1994 that prohibited the use of most defense standards without a waiver.[1] This has become known as the "Perry memo". Many defense standards were canceled. In their place, the DOD encouraged the use of industry standards, such as ISO 9000 series for quality assurance. Weapon systems were required to use "performance specifications" that described the desired features of the weapon, as opposed to requiring a large number of defense standards. In 2005 DOD issued a new memorandum[2] which eliminated the requirement to obtain a waiver in order to use defense standards. (The memo did not reinstate any canceled defense standards.)

According to a 2003 issue of Gateway, published by the Human Systems Information Analysis Center [4], the number of defense standards and specifications have been reduced from 45,500 to 28,300. However, other sources noted that the number of standards just before the Perry memorandum was issued was less than 30,000, and that thousands have been canceled since then. This may be due to differences in what is counted as a "military standard".

Everybody has heard of the million dollar government hammer from a few years back. The hammer was actually a cover story to hide the cost of another project that was to remain hidden from the public. OK, enough history of military specs. As Boozcat stated. Mil Spec caps should be on everybody list to purchased. These baby's are defiantly shielded and will protect your pickup circuit from stray interference.

Tim said:

As Boozcat stated....

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Now, that would explain all the capactor and cloth-covered wire mumbo-jumbo! :rotflmao:

Only kidding, guys. I find all the capacitor stuff very interesting, though I suspect there are elements of myth mixed in with what can be explained scientifically.

And thanks for that Mil Spec explanation, Tim. As a QA manager for 25 years, I kind of take Mil Spec concepts for granted, but many folks are completely unaware of what they're all about.

duhvoodooman said:

And thanks for that Mil Spec explanation, Tim. As a QA manager for 25 years, I kind of take Mil Spec concepts for granted, but many folks are completely unaware of what they're all about.

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I retired with 36+ years working for Uncle Sam. I started out as an aircraft mechanic. Worked my way up to a QA Inspector and crossed over to the production side. From there I went to different Programs Offices (buying agencies) were I ensured contract performance. I ended up as a staff Supply Chain Manager. Now I am an independent ISO auditor. One of the things I check for is compliance of Mil Specs and correct documentation and certificates.

This site is a wealth of knowledge, isn't it? :AOK:

Bloozcat said:

This site is a wealth of knowledge, isn't it? :AOK:

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And you are one of many great contributors. :master: :bravo: :master:

Tim said:

And you are one of many great contributors. :master: :bravo: :master:

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Thanks for the kind words, Tim.

BTW: I never knew you had (have) :AOK: such an interesting career...

Thanks all this is a great thread:AOK:

M29