Using HIGH quality capacitors help tone

[PTChristopher]

Although no tone cap enthusiast seems aware of it, there is the concept of Dissipation Factor in a cap. "Newsense" addressed it earlier.

I would think that a tone quack would haul this concept out and make up some application of it to sell caps. Maybe someone has.

As best I can see, Dissipation Factor has no practical bearing in our tone circuits. This could be because the change in effective resistance is extremely small compared to the pot in series with the cap already. I have never looked at this in any detail.

It is, in principle, very possible that Dissipation Factor would have a noticeable effect in a much lower impedance circuit. But of course this effect could prove to be non-existent, or so minor that it is easily overwhelmed by component tolerance or the inclusion of a small resistor in series with the cap.

I really do not want to slog through what "impedance" really is. So please excuse the use of this term, which gets thrown around quite a bit when there may not be any common understanding of what it really means.

Chris

[jorgemg1984]

Hi Jorge,

>>> Chris do you think as people listen changes in tone because they want to, you don't hear them because you're rational / tech side is already biasing you to think that? Isn't the psychological argument valid to both sides?

I think the psych argument is absolutely valid in both directions.

I do think that I am open to anything making a difference in sound, but I do need to either hear it myself (with as little predisposition as possible to hearing what is not there) or measure it in some dispassionate way. And then ALSO combine the concept behind the change with the actual change, AND look for other more mundane possible causes for the change.

So some robust examination vs. ecstatic, "I hear it and I'm special!" reaction.

Also, I like to consider the practical scope of a difference. I hear differences from one basic PAF to another. But the differences are so small that they are overwhelmed by things like a 5 degree (or much less) turn of a tone control. So in my view, most deep love for a boutique PAF comes from the "consumer ego experience". Others feel differently.

I hear and measure absolutely no difference whatsoever from one tone cap type to another, with the same actual capacitance value. I see others gushing over differences while ignoring the markings on a cap showing a very wide tolerance of values.

So yeah, I am skeptical and critical of the mix of psych factors and unexamined actual variations.

But 100% agreed that any "it's all in your head" argument works both ways, and I am no less obliged than anyone else to come up with conceptual and empirical support for my observations.

Chris

Thanks Chris. The difference is I cannot back up my own claims because I don't have the technical backgrounds. But I do hear an audible difference between a PAF Gibson Classic 57 / PAF Bare Knuckles Stormy Monday and a Geroge Ls / Sommer Grindycop Beast cable. Not a big difference but still significant and relevant to me. But of course I can be biased to think this way!

[newsense]

Although no tone cap enthusiast seems aware of it, there is the concept of Dissipation Factor in a cap. "Newsense" addressed it earlier.

I would think that a tone quack would haul this concept out and make up some application of it to sell caps. Maybe someone has.

As best I can see, Dissipation Factor has no practical bearing in our tone circuits. This could be because the change in effective resistance is extremely small compared to the pot in series with the cap already. I have never looked at this in any detail.

It is, in principle, very possible that Dissipation Factor would have a noticeable effect in a much lower impedance circuit. But of course this effect could prove to be non-existent, or so minor that it is easily overwhelmed by component tolerance or the inclusion of a small resistor in series with the cap.

I really do not want to slog through what "impedance" really is. So please excuse the use of this term, which gets thrown around quite a bit when there may not be any common understanding of what it really means.

Chris

I'm going to have a grad student try to measure the effect of dissipation factor on tone along with the alleged piezo effect in ceramic capacitors in the next few weeks - look out for an exciting thread with our report before Christmas !

[PTChristopher]

[Jorge]>>> [the PU difference is] significant and relevant to me.

Hey, if it is significant and relevant to you, then any "argument" is over. For you, it is an important distinction.

I was trying to think of an example of some sound difference I heard recently.

I built a new very small carved archtop this winter and used a Benedetto S6 in it. In this guitar, the weakness of the B string through the S6 (oops, not really "through") was particularly noticeable. So the "examined life" approach went more or less:

- Hey, the B is weaker than expected.

- Right but as wound-G set players we are sort of predisposed to go easy on the B to balance many guitars and PUs out. Maybe you are overcompensating.

- OK, lets play a passage on this guitar and on a few others. Try to not react to the sound, just play.

- Still noticeably weaker than expected. Lots of possible personal bias, but that sure sounds weak in the B.

- Call Seymour Duncan support.

- The kid reads the marketing literature. I wait for him to do the dance.

- I ask him if he can go back to manufacturing and pull some S6 blades and describe them to me. If you do not sound like an escaped mental patient (or hair-triggered handgun enthusiast, or other sort of patent weirdo) the folks at SD will go to great lengths to get you actual info. Great company.

- Sure enough, while the B6 blades have a taper at the low E and A, the S6 blades have a very big divot cut out under the B.

Now I could have gone on with measurements. But to me this was far enough.

Found an issue.

Tried (possibly not with 100% success) to isolate my personal view from the issue.

Did not make 100% objective measurements, BUT instead went to look for a physical or conceptual reason for the observation.

Found an extremely clear reason for the observation.

So I left it at that. The S6 is arguably overcompensated for the strength of the B string in many applications.

But move the PU away from the strings some and it sounds quite a bit better balanced (which makes sense).

Consider that some may want to use bronze-wound strings, and then the design (while still sub-optimal in my opinion) is understandable.

Chris

[PTChristopher]

Newsense,

If possible can you characterise the Dissipation Factor differences as resistance values, and consider the relative importance of these differences in both the very high impedance passive circuits in our guitars and the MUCH lower impedance inside an audiophile's home amplifier?

I am thinking that it may be possible that the absolute difference may be genuinely important once the impedance gets low enough to make the relative difference of some practical consequence.

Looking forward to the holiday report. Many thanks.

Chris

[PTChristopher]

Newsense,

Are you at the U of Leeds?

In 1976 I applied to go there though the UCCA. I suspect they are still laughing at the idea of an American public high school student expecting to get into the university.

So I went to a US university instead - as you can see, the results are un-amazing.

Haven't been to Leeds in easily 10+ years. Stayed at 42 The Calls as I recall. Nice hotel.

Chris

[newsense]

Chris

Yes - I am at U of Leeds. What subject were you going to study ? I was there as a grad student from 80 to 83 and found myself back there in 2000 as a prof. We now welcome US students with open arms - especially if they pay cash !

[PTChristopher]

In high school I had blown through all the physics and electronics classes the school had by my second year, so I did various independent studies for my last two years. It was fun. Lots of both analog and digital circuits. Made a gizmo the prove Plank's Constant for the classrooms. Wrote long arguments about maybe how the high school should not teach the atom as a solar system. Was told to be less of an annoyance. Some things never change.

But my girlfriend's various squoozhy bits were still more the highlight of those two years.

Anyway my interests were physics and oddly enough Phys. Ed. - I like sports.

And why do you Britons say Maths and Sport? There is only one Math, yet many varied Sports?

I can not recall the details of my application. I had found a sort of catalog of classes from the University of Leeds at the Boston Public Library in 1975 or so. Until then I only knew of "Live at Leeds".

>>> We now welcome US students with open arms

I did eventually manage to more than satisfy a global wanderlust. But I still wonder what life would have been like under other circumstance. You did have girls in Leeds in the mid/late 70's I suppose?

My actual degree was in a completely other direction.

Chris

[jorgemg1984]

[Jorge]>>> [the PU difference is] significant and relevant to me.

Hey, if it is significant and relevant to you, then any "argument" is over. For you, it is an important distinction.

I was trying to think of an example of some sound difference I heard recently.

I built a new very small carved archtop this winter and used a Benedetto S6 in it. In this guitar, the weakness of the B string through the S6 (oops, not really "through") was particularly noticeable. So the "examined life" approach went more or less:

- Hey, the B is weaker than expected.

- Right but as wound-G set players we are sort of predisposed to go easy on the B to balance many guitars and PUs out. Maybe you are overcompensating.

- OK, lets play a passage on this guitar and on a few others. Try to not react to the sound, just play.

- Still noticeably weaker than expected. Lots of possible personal bias, but that sure sounds weak in the B.

- Call Seymour Duncan support.

- The kid reads the marketing literature. I wait for him to do the dance.

- I ask him if he can go back to manufacturing and pull some S6 blades and describe them to me. If you do not sound like an escaped mental patient (or hair-triggered handgun enthusiast, or other sort of patent weirdo) the folks at SD will go to great lengths to get you actual info. Great company.

- Sure enough, while the B6 blades have a taper at the low E and A, the S6 blades have a very big divot cut out under the B.

Now I could have gone on with measurements. But to me this was far enough.

Found an issue.

Tried (possibly not with 100% success) to isolate my personal view from the issue.

Did not make 100% objective measurements, BUT instead went to look for a physical or conceptual reason for the observation.

Found an extremely clear reason for the observation.

So I left it at that. The S6 is arguably overcompensated for the strength of the B string in many applications.

But move the PU away from the strings some and it sounds quite a bit better balanced (which makes sense).

Consider that some may want to use bronze-wound strings, and then the design (while still sub-optimal in my opinion) is understandable.

Chris

On one hand I wish I had all your tech knowledge to back up my own tone ideas. On the other hand I glad I don't have it, I am 100% focused on music. But it's good to have an input like yours (and some other members) that is based on science and not on fiction.

[newsense]

>>> And why do you Britons say Maths and Sport? There is only one Math, yet many varied Sports?

I guess it's because that's the way we defined the language

>>> You did have girls in Leeds in the mid/late 70's I suppose?

Indeed we did - in fact I married one of them

[tele jazz]

doesn't really matter. following reasons -
1, whatever the capacitor it has a value and a tolerance. the closer to the tolerance the more reliable the value.
2, guitars are generally not active so the effect of the capacitor is not the same effect how it is used in HIfI equipment. i.e. it is wired to a resistor (the pot) and only modifies that value.
3, life is too short

[Elias Graves]

I've checked in on this thread from time to time but I quickly came to believe that my time was better spent practicing. It occurs to me that the most time consuming and detailed gear discussions always seem to revolve around the gear that has the smallest impact.

Amen

[Elias Graves]

I got Elias' nose out of joint

Your opinion has no impact on my nose.

[FrankyNoTone]

I'm going to have a grad student try to measure the effect of dissipation factor on tone along with the alleged piezo effect in ceramic capacitors in the next few weeks - look out for an exciting thread with our report before Christmas !

That would be excellent! It could shake things up if it was shown that the use of low grades of ceramic caps in heavily vibrating and/or low signal environments like guitars or combo amps was causing a problem. I don't want to do too much work for your grad student but here are some references:

Piezoelectricity is a common characteristic of many ceramic chip capacitors and occurs in those classes of dielectric which are classified as ferroelectric. Piezoelectric effects can result in noise for ferroelectric ceramic chips, such as those used for military BX & BR, as well as commercial EIA Class 2 and Class 3 dielectric, such as X7R, X5R, X8R, Y5V, Y5U, Z5U, etc. Piezoelectricity occurs in all ferroelectric dielectrics, regardless of manufacturer. Note that there are essentially no piezoelectric effects in Class 1 capacitors, such as C0G, NP0, or military BP - none of which are ferroelectric.

Piezoelectric noise is only occasionally an issue, since it is low level. However, it can show up in specialized applications subject to mechanical stress of the ceramic during shock, vibration, compression, and torsion. Examples include high gain pre-amps, hand-held microphones at rock concerts, and monitoring equipment subjected to sudden shock or heavy vibration. When it occurs, most piezoelectric noise is in the 3 KHz to 30 KHz ranges, although detailed studies have not been done over a wider range.

KEMET Electronics - Are your military ceramic capacitors subject to the piezoelectric effect?

In addition, the generation of electric charge or potential by mechanical vibration contributes a significant noise to circuit applications. Voltage levels were in the millivoltage range. The study indicates that significant problems may arise in commercial ceramic multilayer capacitors due to a generally unrecognized piezoelectric effect.

IEEE Xplore - Piezoelectric Measurements on Ceramic Multilayer Capacitors

[Spook410]

That opinion perhaps could be better aimed towards guitar gear only, for it certainly doesn't fly in the audio kingdom, for it makes as much sense as the earlier statement suggesting "all amps sound the same."

Caps matter. If you think they don't you've not heard the difference between paper and oil caps, vs. also ran's. 40 years of listening to good gear versus ordinary gear will teach one to trust their ears...besides, quite the contrary, the spec's which are tested under all conditions support what the ear is hearing. Distortion is either extremely reduced or it's not. Generally the better the gear the lower the point of distortion. This is basic elementary stuff gathered from any Stereophile or other type audio magazine that have been in circulation for 40 years. But one doesn't need to read a single article to tell them what their trained ears already have. There's more to good gear than just marketing hype, imo.

Unless you've exceeded the power handling of the cap, things like dielectric absorption, resistance, damping (just from the cap), etc. just aren't in the frequency range of the human ear. Run something nasty and telling like a square wave from a really good generator through a $3 cap and you won't see a thing at the edges in audible frequency range. It's been awhile but I have actually done this. I'm not an expert. Not even close. But I know enough to be confused and baffled. You're a smart and attentive person and I believe that you and thousands of other audiophiles believe they are hearing something significant attributable to that single variable. I'm just not seeing the science or math backing it up in the simple RC world I'm used to. Still, I am perfectly willing to accept that this is because I haven't gone and done my diligence on the edges of capacitor performance as they apply to hi end audio gear.

As for guitars.. I like the orange ones because they look cool and the leads are big enough for my crappy soldering.

[2bornot2bop]

As for guitars.. I like the orange ones because they look cool and the leads are big enough for my crappy soldering.

Orange caps sound pretty kewl, especially on a vintage orange archtop!

[PTChristopher]

[Jorge] >>> I wish I had [...] tech knowledge to back up my own tone ideas.

In my opinion it is not so much tech knowledge, but a sort of inclination to peel away at the onion.

If you solve this sort of problem for a living, then the smarmy answer, "This is all beneath me and my time, yet I have time to point this out." does not cut it.

Likewise if you start to make up new principles of electronics, you will fail your customers - and of course yourself.

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

The nice thing about higher voltage "orange" caps, as Spook mentions, is that they are very luthier friendly. Feeding a 4-pot array through into an archtop is easier if you have a nice strong cap (and its leads) to hang in there as you fat-thumb the whole mess into place.

Chris

[newsense]

SKIP THIS POST IF YOU ARE BORED BY THE SCIENCE STUFF

KEMET Electronics - Are your military ceramic capacitors subject to the piezoelectric effect?

IEEE Xplore - Piezoelectric Measurements on Ceramic Multilayer Capacitors

Franky thanks for the references -

Even though I know and respect some of the guys at Kemet, I am still a little sceptical about how significant this problem may be. What they say about the caps being ferroelectric and therefore potentially piezoelectric, is, as I said above, essentially correct. Virtually all Type II and III caps are based on barium titanate, albeit modified with other oxides in a way which "dilutes" the piezoelectric effect. However, as these caps are all ceramic and therefore polycrystalline, as-manufactured they are isotropic - the ceramic grains are oriented randomly with respect to each other. Hence the cap will show zero piezoelectric effect immediately after manufacture. But if the cap is then exposed to a high dc voltage or electric field (> 1kV/mm) it becomes "poled" - the ferroelectric domain structure in the ceramic is reorganised to be anisotropic and hence becomes weakly piezoelectric. All caps are tested at twice their rated dc voltage before release from the factory, so it is conceivable that some caps have been unintentionally poled during factory test.

How important this then might be depends upon (a) the mechanical arrangement of the cap - leaded caps should be less prone to microphony as at audio frequencies you need good contact with the ceramic to transmit the pressure wave through it, and (b) the circuit - the reference in the Kemet article to generation of millivolts was a little naive, as the voltage generated by piezoelectricity depends on the impedance seen by the cap in the rest of the circuit.

Should we be concerned anout the piezo effect in guitar tone caps ? Until I have tested it myself, I will remain a little sceptical, but to avoid the possibility I suggest: (i) use a polyester cap or (ii) depole your ceramic cap by heating it to greater than 120C whilst shorted. In this case I suggest removing it from your guitar first.

[jazzbow]

>>> garden variety caps

A few years ago I was trying to buy a volume pedal. The guy (kid, really) showed me a volume-wah, volume-toaster, volume-centrifuge, but no basic volume pedal.

I said I wanted a "garden variety" volume pedal, and he took out the supplier book and looked under "G". Really.

Chris

Hey Chris'
methinks you better copyright that name 'cos some boutique pedal maker will steal it!!

I can see it now.... Garden Variety Brown Sound, for that woman tone

[SamBooka]

As for guitars.. I like the orange ones because they look cool and the leads are big enough for my crappy soldering.

Exactly.. I use bumblebees purely for the snob appeal.

[oldane]

I now realize my immense ignorance. I have been playing guitars for 45 years. I have obsessed about strings, picks, setup etc. But I have not even once given those caps a thought.

[PTChristopher]

>>> But I have not even once given those caps a thought.

I think the OP had a perfectly valid question. It just opened up a whole can of worms about bunk, de-bunk, guitar myths, audiophile culture, and many new (and creative, if not genuine) theories about how circuits work.

A weird thread, but fairly interesting in many ways.

[Jimmy Mack]

I like your straightforward answer Jim, practicing being the most worthwhile investment of one's time.

I won't dismiss the importance however, of good gear and some of the modifications easily obtained. To me, a great sounding/playing guitar deserves a good amp with a good speaker, and good servicing tubes. I have swapped these out many times, only to be rewarded with better tone and better responses in the "feel" of an amp. If not attainable easily, it's time for the equipment to go. Sometimes the guitar has to go on to a new home! But, a good cable from guitar to amp is also essential.

Once you have all that working, the little things like tone caps are, to me insignificant. The main performers in the chain either have it or they don't. But guitar pots, at the wrong value, are gonna hurt your tone.

[SamBooka]

Sorry to mention it...

Builder Profile: Chase Tone - Premier Guitar

The fun begins at Tell us about some of your builds.

[oldane]

Sorry to mention it...

Builder Profile: Chase Tone - Premier Guitar

The fun begins at Tell us about some of your builds.