Using HIGH quality capacitors help tone

[jazzbow]

Well, back to guitars and capacitors (I hope no one will object....ahem )!

I got me a Squier JM Jazzmaster some time back and changed out the pots and capacitor on the lead circuit and the cap on the rhythm circuit as it was too twangy for these old ears.

I really liked film and foil caps but after tweaking a single coil hollow bodied guitar with orange drop caps I decided to use them instead.


Original pots and caps on the lead circuit, unsure of pot value but nice soldering.


Replaced pots and cap. Cap is O/Drop and pot value 500k volume & 250k tone.
Since replacing these components I find the tone really usable and the volume output colours the tone as well.


Original pots and caps for the rhythm circuit. I would like to replace the pots but maybe later. The mylar cap here fell apart when it was desoldered.


Here's the fat cap replacement. maybe that should be 'PHAT.'
Playing on a EL84 40 watt combo, the tone on this circuit is clearer, not so much mud but thicker lows and the highs stay around a bit longer as you dial in that cap. The amp tone controls needed to be rejigged for taste and I must admit, for me the guitar tone is really useful now.

There is a lot of hear say and voodoo on the capacitor question for guitar circuit but for a cheap mod it's fun and if you don't like you can replace the old caps. I wouldn't spend lots of cash for a cap, £2/$3 max, and not intrusive on the look of your guitar.
Certainly the you tube clip on the above post will have your head spinning on which, what, woah and why?!?

So to recap (pun intended), experiment and find what suits your ears, if you want to spend loads of cash speak to a tech (name and address supplied) and they will put on what you want and charge accordingly.

Talking of chasing tone dragons check this out, mega choices and new technology.
ToneShaper | ToneShaper for Strat & Tele | ToneShaper Parts | ToneShaper Swtiches | Acme Guitar Works

Hope this helps.

[PTChristopher]

>>> On most forums I frequent, "there's no such thing as a stupid question", but on here, I have seen, there most certainly IS.

Well it seems more like a recent rash of relative newcomers (a good thing) who pose a question, get opinions - then are upset to not find the responses they were looking for.

It happens. Maybe somewhat less at a Dukes of Hazzard fan website or something.

The OP got some feedback, and even eventually the kindred-spirit audiophile enthusiasm that seemed to help.

[newsense]

As someone who has spent the last 25 years developing and manufacturing capacitors for a living, both in industry and universities, I feel as though I should provide some input to this discussion, but to be honest I'm not sure I will provide much joy to the OP.

I understand capacitors in terms of the polarization mechanisms in the dielectric materials, the comparative technical merits of ceramics, polymers, electrolytics and even paper and oil, and how these effect phase angle, tan delta, frequency dependence, temperature dependence, voltage dependence etc. I measure these things and write technical papers about them as my day job, but I have to say that for the purpose of providing tone control on a guitar, a 1 cent ceramic capacitor is as good as it gets. There really is no point in looking for anything different. Yes, you can buy capacitors that are more expensive, but that higher price doesn't buy you better quality in terms of the audio performance of an individual capacitor. It may buy you better reliability against high voltage breakdown - but that it irrelevant unless your guitar gets struck by lightning. It may buy you better in-batch tolerance - nice if you are building thousands of guitars and you want the tone control of everyone to be identical. However, if you are expecting two capacitors of the same technical specification (capacitance and loss tangent within the audio frequency range) to sound different, I believe you will be disappointed.

I am happy to be corrected about this, but please provide physical reasons as to why one capacitor should sound better than another one. At present I cannot think of what those reasons might be.

[PTChristopher]

Hi Newsense,

Thanks for the post. Of course you will be unwelcome at the next Capacitor Druid festival. I hear it involves nudity, but just for middle aged guys.

But back on earth, can you comment on the practical (if there are any) aspects of the dissipation factor in various capacitor technologies when used in passive guitar tone controls.

I have absolutely never heard any difference whatsoever between one cap type and another.

I have seen caps in guitars rated at +80% / - 20% of the marked value, which is sort of funny.

And the all time classic is the Fender "Integrated Circuit" capacitor, known for its musicality. And fortunately manufactured by Illinois Capacitor, so the "IC" marking makes sense - in a sense. Note that this amazing (noted for its musicality) cap is rated +/- 20% of marked value.

Fender Guitar Upgrade Capacitor 0.02MFD 50V IC | Musician's Friend

To be clear as is apparently needed these days: There is no such thing as a discrete component called an "Integrated circuit" capacitor. The Fender cap is a +/- 20% tolerance ceramic disk cap made by Illinois Capacitor. Now I hear that Illinois Capacitor has a great in-house polka band (and gun club), but their capacitors are otherwise not known for their musicality.

Chris

[newsense]

Hi Chris
I'm all for nudity - but in the privacy of my own shower.

It's getting a litttle late here in the UK to start thinkking too deeply about dissipation and tone controls - so I will leave that for a post tomorrow evening. However, I will say a few words about tolerances.

As I am sure you know, the tolerance rating on a capacitor is simply telling us that the manufacturing process is not sufficiently precise to hit the required capacitance value dead on. +/- 20% is quite a wide tolerance and you can get better if you pay more. Such capacitors are not made any differently, the manufacturer just selects them from within the batch to fit within the tighter tolerance band. Hence they are not intrinsically higher qaulity. The influence of tolerance on the tone control is that the roll-off frequency will vary between one capacitor and another from the same batch, - the wider the tolerance, the greater the variation of roll-off frequency within that batch of caps. If this is critical, one should always measure the capacitance of each component before use to check how near it is to the specified value. Even the +/- 20% tolerance of the Fender cap shouldn't influence its musicality, but there again, I can't think of why any capacitor should be more "musical" than another.

I'm not sure which manufacturer would own up to having a +80/-20% tolerance window - that just sounds like incompetence - or a misprint.

[PTChristopher]

>>> I'm not sure which manufacturer would own up to having a +80/-20% tolerance window - that just sounds like incompetence - or a misprint.

I have pulled ceramic caps out of guitars with a "Z" tolerance rating, so +80/-20%.

>>> +/- 20% is quite a wide tolerance and you can get better if you pay more.

The Fender "Integrated Circuit" capacitor is available to retail customers for about 12 cents as an Illinois Capacitor ceramic disk +/- 20%. It is also sold via music dealers for something like $2.50 as the "musical" Fender "Integrated Circuit" capacitor (same manufacturer, same tolerance).

Thanks again for the posts.

Chris

[Elias Graves]

The caps in a guitar are part of a passive system. Big bux caps won't do much.
Any decent quality capacitor will do the job just fine.

Caps have a much bigger impact in active systems like an amp or a hi fi setup. In a guitar, not so much.

[PTChristopher]

Gents,

Is it possible that we are making stuff up again?

Exactly what physical property of various capacitors makes a difference in an active circuit, and no difference in a passive one? Do you mean to suggest that impedance is the issue? If so, the question of what physical property remains? Is it total wattage? Then what is happening at a higher power level that is not happening at a lower one?

Electrical circuits are not like corridors in a building. Exactly what makes a cap through which the signal passes somehow subject to influences of the materials used to make it, but a capacitor through which some signal is shunted to ground not subject to these same (claimed) influences? Do the electrons know they are destined for the dustbin of history?

If we are just making things up, or "read it somewhere" maybe we should find a way to distinguish that from other views.

Chris

[Klatu]

Hi Newsense,

Thanks for the post. Of course you will be unwelcome at the next Capacitor Druid festival. I hear it involves nudity, but just for middle aged guys.

Hi Chris
I'm all for nudity

Sheesh you two . . . get a room!

All kidding aside, that bit about getting the same $2.50 Fender cap for 12 cents is eye opening.

[PTChristopher]

I guess maybe it costs much of $2.50 to pass a plastic bag through distribution to GC and into our hands. So while Fender may not be getting rich on the capacitors - the flow of ideas is interesting.

1. Buy very cheap (far less than 12 cents each to FMIC) completely unremarkable ceramic capacitors for use in Fender guitars. They work fine, and at 20% tolerance give players a genuine opportunity to find differences from one guitar to the next,...

2. Pack and sell them as genuine replacement parts.

3. Make a bunch of absolute twaddle up about "Inegrated Circuit" capacitors and their musicality, and then feed the sales copy through the retail chain.

Makes you wonder abut the stuff you "read somewhere" that is not so easily taken apart.

I guess I hope we can maybe at least filter out the "making stuff up" and "I read somewhere" part. It really does make it much easier to genuinely understand guitars.

In my opinion.

Chris

[FrankyNoTone]

Well, this is turning delightfully techy

Regarding capacitor types making an audible difference in a guitar, yes absolutely: some capacitors, interestingly some ceramic ones, suffer from microphonics like tubes do (vibration altering the plate spacing) and/or like piezo pickups and/or like electret mic's.

Now whether this is bad, or good like the classic "strat sound" caused by the tremolo springs vibrating is up to the listener I guess. But its hardly something that is easily controllable.

Regarding audible differences by humans, that's more or less magic. Humans suffer from strange things like the placebo effect and what we hear is only partially determined by what goes in our ears. So I'll leave it at that.

Like I said previously, I'd just rip out the tone circuit in the guitar altogether.

[rockrink]

River,

I only hope my playing gets good enough to focus on the caps. I'm hopeful you'll post your findings here, and don't focus too much on someone else's agenda. You may have just caught him on a bad day.

R

[Elias Graves]

Gents,

Is it possible that we are making stuff up again?

Exactly what physical property of various capacitors makes a difference in an active circuit, and no difference in a passive one? Do you mean to suggest that impedance is the issue? If so, the question of what physical property remains? Is it total wattage? Then what is happening at a higher power level that is not happening at a lower one?

Electrical circuits are not like corridors in a building. Exactly what makes a cap through which the signal passes somehow subject to influences of the materials used to make it, but a capacitor through which some signal is shunted to ground not subject to these same (claimed) influences? Do the electrons know they are destined for the dustbin of history?

If we are just making things up, or "read it somewhere" maybe we should find a way to distinguish that from other views.

Chris

In a guitar, the signal you hear does not even pass through the capacitor. It merely bleeds parts of the signal to ground. It is, therefore, not possible for the capacitor to influence the tone; only how and how much signal gets bled off.

I don't make things up for the benefit of strangers.

[PTChristopher]

Hi Elias,

I agree that the capacitor technology does not affect sound. But saying this can be upsetting to what is commonly sold in the "industry".

I hope we can try to not get overly imaginative about the technical side of this.

>>> In a guitar, the signal you hear does not even pass through the capacitor.

The idea that you hear a signal "passing through" anything, like water through a pipe, is a convenient analogy, but can be very misleading if we use this analogy to analyze.

Yes, the common tone cap, mostly via capacitive reactance, shunts some degree of higher frequency signal to ground. But the exact profile of the shunted signal does influence what you hear as the remaining signal.

It is not at all accurate to describe components as having no effect because they are not in the "signal path" as if it were a water pipe.

If a larger cap affects the sound (and it does), so will any characteristic of the cap that changes the profile of what is shunted to ground.

Now in my opinion, the technology of the capacitor has no practical impact at all, but not because it is "out of the signal path".

>>> I don't make things up for the benefit of strangers.

I understand. But when we say things that are really based what may be a misapplied analogy (I certainly find myself doing this at times, and I work to correct it), we end up back where much of the various guitar myths start.

Tricky subject for several technical and social reasons. Sometimes I think many players very much want to believe certain things, and that it can seem harmful to say otherwise.

My first bout with this was in the brass nut craze. Players truly believed that the brass nut would provide more sustain, and I was installing them by the dozens for a good 18 months. My fingertips still hurt. Do I tell the guy that the brass nut will have no effect whatsoever on the sustain of any fretted note? He'll get all upset - everyone says otherwise and will make up all sorts of crap to support it. Do I tell him it will have more sustain? This would be a complete pant-load, but a motivating and enjoyable (to him) part of a craze.

Tricky.

I played it by ear and let the customer lead the discussion of expectations. I may have been wrong to do it. But look what happens when you take the other path?

This can be an environment where misapplied analogies are used all over the place - making stuff up.

It sounds ridiculous when we say:

"Her sweater was blue like the sky."

"So when there was a drop in barometric pressure, it would turn gray and drip a lot."

Analogy can illustrate in a very limited way, but can also mislead terribly when misapplied.

Chris

[FrankyNoTone]

...
Analogy can illustrate in a very limited way, but can also mislead terribly when misapplied.

Chris

Oh let me try for fun:

What remains of the signal sent to the amp after the tone cap bleeds part of it to ground is like being given an apple with a piece taken out of it. You'll definitely know whether someone bit it off by the teethmarks (bad cap) or whether a knife was used (good cap). And that will determine how palatable that apple is.

[PTChristopher]

Are they false teeth? I hear you can get old Soviet-Era teeth that bite exactly like the original PAF teeth did?

[ruger9]

Good lord and I thought TGP was bad for such "minutiae" and trying to prove points with semantics. This thread has turned painful.

I've been here long enough to know that if PTC doesn't already know it, it must be made up. Come on people- get with the program!

[kenbennett]

Yes, the common tone cap, mostly via capacitive reactance, shunts some degree of higher frequency signal to ground. But the exact profile of the shunted signal does influence what you hear as the remaining signal.

This is obviously true. I don't know why I said otherwise. Maybe I wanted to see what the "reactance" would be.

[PTChristopher]

Hiya Ken,

Yeah, I make goof-ups all the time when we have to switch from mechanics, to electronics, to wood, to lacquer. It's a complicated pile of guitar stuff.

As for "reactance" this is a pretty weird thread - probably partly because of the beliefs involved?

>>> if PTC doesn't already know it, it must be made up.

Har-har.

There is stuff I just happen to have done badly enough times and over long periods of time - so eventually you happen to figure it out both in concept and in practice.

I do try to watch out for making stuff up. It almost always comes form making an assumption without thinking it through, or without actually trying it on a guitar, or without measuring the assumed effect.

I guess goofy stuff also comes from repeating things from questionable sources. There are wackier guitar forums out there.

Anyway, lots of great input around here and I sure benefit from new chances to walk through the burning issues of guitars.

Chris

[FrankyNoTone]

Are they false teeth? I hear you can get old Soviet-Era teeth that bite exactly like the original PAF teeth did?

In some situations, you can tell if the bite was taken with false teeth because they remain in the apple .

This is the analogue to the microphonics effect I mentioned earlier, which can be an issue in guitars and combo amps because of all the vibration present.

Here's a good article on tone caps that debunks a lot of myths:
Atlantic Quality Design, Inc., The Truth about Tone Capacitors

[PTChristopher]

Hi Franky,

>>> old Soviet-Era teeth

Hey, I think Soviet-era false teeth were stainless steel. So maybe some galvanic corrosion as well in that apple.

Thanks for the link. I have never done anything like such an exhaustive test, only run signals through and looked at the scope to find (gasp) no difference on a few caps when the question came up.

>>> the microphonics effect I mentioned earlier

I understand the effect you mention, but wouldn't the microphonics in a ceramic cap result in a miniscule modulation in the capacitance only? I figure this would have an extremely small effect.

Oh Gahd, the pain of minutiae.

Thanks again for the link to the study.

Chris

[FrankyNoTone]

...I understand the effect you mention, but wouldn't the microphonics in a ceramic cap result in a miniscule modulation in the capacitance only? I figure this would have an extremely small effect...

Depending upon the ceramic, I believe piezo effects can also occur, i.e. actual electric generation.

But yes, its probably a very small effect, yet there should be no difficulty in avoiding such capacitors and just use a reliable low cost plastic cap.

[PTChristopher]

>>> Depending upon the ceramic, I believe piezo effects can also occur, i.e. actual electric generation.

Ah, that had never occurred to me.

********************************

Despite the reported personal angst regarding this thread, I have learned a thing or two about capacitors.

I had not thought through the concept of dissipation factor in decades. And the concept of microphonics in a ceramic cap seems obvious enough - but only after Franky pointed it out.

So, many thanks.

Chris

[newsense]

I still owe Chris an explanation of the influence of dissipation factor on the tone circuit. I had thought about doing a full impedance analysis of the circuit so that I could say accurately what the effect would be on the harmonic content of the signal to the amp. An accurate treatment needs to account for the inductance and resistance of the pickup as well as the input impedance of the amp - but if I did that I wouldn't have time to play the guitar tonight. As it is my first night back with my guitars after three weeks of travel - that is a non-starter ! So here is the hand-waving version.

We usually account for the dissipation factor of a capacitor in a circuit as a resistor in parallel with the (ideal) capacitor. The dissipation factor is the ratio between the impedance of this imaginary resistor to that of the capacitor at a specified frequency. Hence, for a capacitor with a tan d = 0.01 at 1 kHz, the impedance of the imaginary resistor will be 100 times that of the capacitor, meaning roughly 1% of the current is passed by the resistor compared to the capacitor, but in a somewhat frequency independent manner. The effect of this is that the tone circuit does bleed off a little of the total signal below the high cut-off set by the tone pot, and would be most noticeable, if at all, as a slight loss of volume at low frequencies.

I am beginning to wonder whether I should eat my words form yesterday, as using a cap with a lower diss factor would of course reduce this effect, meaning the low frequency signal loss would be less noticeable. But, does this effect represent a degradation of tone or is it all just part and parcel of the way passive tone controls work ? Changing the cap value itself would have a far more profound influence on the operation of the tone control than would swapping a cap for one with a lower diss factor.

As for the cap acting as a piezoelectric pickup - this idea does have some basis of truth. Ceramic capacitors are manufactured from barium titanate. Pure barium titanate is indeed piezoelectric. It has the same crystal structure as lead zirconate titanate (PZT) from which the majority of piezo ceramic pickups are manufactured. However, for capacitors, the barium titanate is highly modified by the addition of other oxides to flatten out its temperature dependence of capacitance. These additions virtually destroy all the piezoelectricity so that it is barely measurable.

Most of my work these days is in developing new piezoelectric materials for industrial applications. PZT is in danger of being banned in Europe, Japan and elsewhere due to its lead content. It is not yet actually banned due to its life saving applications in, for example, medical imaging transducers (and, of course, guitars), but we are still trying to find lead-free alternatives. Unfortunately, I have yet to find anyone who will fund my dream project of developing a new piezoelectric material specifically for guitar pickups, without the non-linearities which lead to the typical "scratchy" response.

[Elias Graves]

Hi Elias,

I agree that the capacitor technology does not affect sound. But saying this can be upsetting to what is commonly sold in the "industry".

I hope we can try to not get overly imaginative about the technical side of this.

>>> In a guitar, the signal you hear does not even pass through the capacitor.

The idea that you hear a signal "passing through" anything, like water through a pipe, is a convenient analogy, but can be very misleading if we use this analogy to analyze.

Yes, the common tone cap, mostly via capacitive reactance, shunts some degree of higher frequency signal to ground. But the exact profile of the shunted signal does influence what you hear as the remaining signal.

It is not at all accurate to describe components as having no effect because they are not in the "signal path" as if it were a water pipe.

If a larger cap affects the sound (and it does), so will any characteristic of the cap that changes the profile of what is shunted to ground.

Now in my opinion, the technology of the capacitor has no practical impact at all, but not because it is "out of the signal path".

>>> I don't make things up for the benefit of strangers.

I understand. But when we say things that are really based what may be a misapplied analogy (I certainly find myself doing this at times, and I work to correct it), we end up back where much of the various guitar myths start.

Tricky subject for several technical and social reasons. Sometimes I think many players very much want to believe certain things, and that it can seem harmful to say otherwise.

My first bout with this was in the brass nut craze. Players truly believed that the brass nut would provide more sustain, and I was installing them by the dozens for a good 18 months. My fingertips still hurt. Do I tell the guy that the brass nut will have no effect whatsoever on the sustain of any fretted note? He'll get all upset - everyone says otherwise and will make up all sorts of crap to support it. Do I tell him it will have more sustain? This would be a complete pant-load, but a motivating and enjoyable (to him) part of a craze.

Tricky.

I played it by ear and let the customer lead the discussion of expectations. I may have been wrong to do it. But look what happens when you take the other path?

This can be an environment where misapplied analogies are used all over the place - making stuff up.

It sounds ridiculous when we say:

"Her sweater was blue like the sky."

"So when there was a drop in barometric pressure, it would turn gray and drip a lot."

Analogy can illustrate in a very limited way, but can also mislead terribly when misapplied.

Chris

I never mentioned water pipes.