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Caps, the truth is out there.

Brek

Member
Joined
May 23, 2020
Messages
41
Did a bit of research as was after a .015uf cap, basically wondering if electronic shops sell interesting caps at less cost than the boutique makers. I found this very interesting article: http://zerocapcable.com/?page_id=224

so any cap in spec will sound the same. Good to know.
 

EpiLP1985

Member
Joined
Aug 11, 2017
Messages
113
Did a bit of research as was after a .015uf cap, basically wondering if electronic shops sell interesting caps at less cost than the boutique makers. I found this very interesting article: http://zerocapcable.com/?page_id=224

so any cap in spec will sound the same. Good to know.

This is a discussion that has been had on multiple forums, privately, etc. for a long time. I think where the conversation gets heated is specifically around PIO caps and I think there is some nuance there with respect to those caps as far as measurements are concerned.

Full disclosure: I'm an electrical engineer by trade but I definitely think that PIO caps may "present" certain characteristics in a circuit that are not commensurate with thier measured values. I don't have reams of data or a solid technical argument formulated but it seems that there are construction variables present that may skew what we hear related to what we measure.

Confirmation bias is a real thing, but I also brew beer, and much like that, tone is very subjective. Therefore, different people perceive sound in different ways.
 

Aloha_Ark

Member
Joined
Apr 2, 2020
Messages
120
Cap differences and whether the ear can hear them has been an ongoing question on every guitar forum out there. There is an old thread on this forum:

https://www.lespaulforum.com/forum/showthread.php?113236-Caps-question-to-the-engineers-out-there

Some people have tried to do comparisons on youtube:


The above uses the "odd man out" technique, which is something that Rick Beato has also employed.

Bumblebee caps are physically and electrically different compared to ceramics, mustard caps, mylar, polyester, and polyethylene. With a $20K Agilent LRC meter, these differences can be measured when you plot the impedance, effective series resistance (ESR), and effective series inductance (ESL) versus frequency. I would bet that there is a thesis out there where a grad student performed such an experiment.

I will not bet my lunch that I can tell the difference between an orange drop cap and a bumblebee cap. I would not dare to sell a vintage LP Jr, GT, or standard where the bumblebee, black beauty, or wax cap was vintage correct, but a ceramic or orange cap was substituted. That would be equivalent to shooting myself in the foot.
 

Brek

Member
Joined
May 23, 2020
Messages
41
It’s a fascinating subject, I think, from my own observations are that the plotted chart may not tell the whole story. It tells the story that the same rated parts do what they are designed to within tolerance that would explain the very minor variances in the traces. But the sound, not as clear cut, maybe. The clips in my the OP certainly sounded the same. I had access to a 1973 minimoog and compared it to my cheap behringer model D. What was evident was the minimoog and the model D produced the same sound, it if you actually listened to the timbre the mini was somehow woody and rounded in tone. Even though the waveforms on oscilloscope looked identical. I have just bought a PIO .015 to stick in my tomato soup burst, had an idea to use the liberated PIO And test the Mylar cap out or my R9 and temporally have them both in circuit but with an A/B switch. If it throws up anything interesting I will upload uncompressed wavs or flacs. I guess this and the other forum have been around long enough that prolly everything has been discussed, it hey it’s all new to me.
 

rockabilly69

Well-known member
Joined
Jul 29, 2001
Messages
2,638
It’s a fascinating subject, I think, from my own observations are that the plotted chart may not tell the whole story. It tells the story that the same rated parts do what they are designed to within tolerance that would explain the very minor variances in the traces. But the sound, not as clear cut, maybe. The clips in my the OP certainly sounded the same. I had access to a 1973 minimoog and compared it to my cheap behringer model D. What was evident was the minimoog and the model D produced the same sound, it if you actually listened to the timbre the mini was somehow woody and rounded in tone. Even though the waveforms on oscilloscope looked identical. I have just bought a PIO .015 to stick in my tomato soup burst, had an idea to use the liberated PIO And test the Mylar cap out or my R9 and temporally have them both in circuit but with an A/B switch. If it throws up anything interesting I will upload uncompressed wavs or flacs. I guess this and the other forum have been around long enough that prolly everything has been discussed, it hey it’s all new to me.

Just clip a alligator clip into the circuit and clip in all the values and types you want to try, if you don't hear a difference, you will get your answer. I do that with all my guitars I plan on rewiring. I like hearing the different values and how they affect the sweep of the tone pot.
 

zacknorton

Active member
Joined
Aug 26, 2011
Messages
540
If you don’t watch those Ann Arbor vids there’s no point in continuing a conversation.

That guy did a brilliant job. Brilliant!
 

mdubya

Active member
Joined
Mar 31, 2010
Messages
855
Who is verifying the viscosity of the oil in the PIO caps? What solder is being used? What effect is the metallurgical make up of the alligator clip in those types of tests having on the the tone?

Eddie Van Halen used a PAF bypassing the tone circuit altogether. What was the value of the volume pot he used? :hmm

I have questions, but I know time spent practicing will be better spent.

JMHO. :peace2
 

Triburst

Well-known member
Joined
Feb 12, 2006
Messages
4,344
The key is getting EVERYTHING right, building it like a recipe for a great dish.

Good wood, good hardware, good pickups, a good wiring harness with good pots & caps, good strings, a proper setup, and good fingers.

Put all that lightning in a bottle, and it’s magic.
 

Deus91

Member
Joined
Apr 28, 2019
Messages
50
My stockpile of bees. My preference, really just a personal thing.
qNQQum6.jpg
5wddciD.jpg
 

blauserk

Les Paul Forum Member
Joined
Mar 12, 2002
Messages
1,758
If you don’t watch those Ann Arbor vids there’s no point in continuing a conversation.

That guy did a brilliant job. Brilliant!

Agreed. Someone should do the same thing running through the capacitors in amps. People could save a lot of money on (e.g.) vintage mustard caps.
 

Big Al

Well-known member
Joined
Apr 24, 2002
Messages
14,294
Cap differences and whether the ear can hear them has been an ongoing question on every guitar forum out there. There is an old thread on this forum:

https://www.lespaulforum.com/forum/showthread.php?113236-Caps-question-to-the-engineers-out-there

Some people have tried to do comparisons on youtube:


The above uses the "odd man out" technique, which is something that Rick Beato has also employed.

Bumblebee caps are physically and electrically different compared to ceramics, mustard caps, mylar, polyester, and polyethylene. With a $20K Agilent LRC meter, these differences can be measured when you plot the impedance, effective series resistance (ESR), and effective series inductance (ESL) versus frequency. I would bet that there is a thesis out there where a grad student performed such an experiment.

I will not bet my lunch that I can tell the difference between an orange drop cap and a bumblebee cap. I would not dare to sell a vintage LP Jr, GT, or standard where the bumblebee, black beauty, or wax cap was vintage correct, but a ceramic or orange cap was substituted. That would be equivalent to shooting myself in the foot.

Nothing matters but the measured capacitence. NO SIGNAL GOES THRU THE CAP IN A PASSIVE GUITAR TONE CIRCUIT. The value of the cap presents a load, a specific load to set frequency point of treble to pass to ground. More, or higher loads, (value expressed by ohms), send more of the highs to ground. That is, a .047 cap presents a larger load which lowers the frequency of the tone sent to ground. All frequencies above that point are attenuated and sent to ground, with the tone pot rolled all the way of, bypassing the output jack.

A smaller value cap, like .015 will have less load and only pass higher than, the larger cap, frequency or only remove less of the highs when rolled off, for a less darker tone.

In amplifiers signal boosted by voltage passes through caps in the tone circuit and type of cap, pio, metal foil, ceramic disc, etc.., has a very real audible effect. IMO, I cannot think of any application in a guitar amp where pio caps offer superior tone or performance, but that's another discussion.
 

Tim

Active member
Joined
Jul 15, 2001
Messages
1,831
It should be noted that capacitance is measured by applying a dc voltage long enough to charge it up and then measuring the amount of time it takes for that voltage to discharge through a resistor when the dc voltage source is taken away. The thing is, that gives a meaningful way to measure, but does not give a real picture as to what is physically happening at higher frequencies. I could see where two capacitors with different dielectric materials could measure the same at dc, but the transients that are going on inside of it at higher frequencies could be different, because the molecules they're made from are different. For more info on how caps are measured, this is a good page.
 

Big Al

Well-known member
Joined
Apr 24, 2002
Messages
14,294
It should be noted that capacitance is measured by applying a dc voltage long enough to charge it up and then measuring the amount of time it takes for that voltage to discharge through a resistor when the dc voltage source is taken away. The thing is, that gives a meaningful way to measure, but does not give a real picture as to what is physically happening at higher frequencies. I could see where two capacitors with different dielectric materials could measure the same at dc, but the transients that are going on inside of it at higher frequencies could be different, because the molecules they're made from are different. For more info on how caps are measured, this is a good page.

Again that is only applicable in amps where voltage and current enter. Why is this so hard? You certainly can measure the load and that static load is all that matters in a passive tone circuit. Not polarity, not wattage and not voltage storing or discharge. I give up you guys can believe whatever unicorn rainbow stuff makes ya moist.
 

Tim

Active member
Joined
Jul 15, 2001
Messages
1,831
Again that is only applicable in amps where voltage and current enter. Why is this so hard? You certainly can measure the load and that static load is all that matters in a passive tone circuit. Not polarity, not wattage and not voltage storing or discharge. I give up you guys can believe whatever unicorn rainbow stuff makes ya moist.

Al, I'm not following you at all. A pickup is a current generating active device and is generating current at each frequency the guitar strings are vibrating. The voltages and currents coming out of it are small but they are there. A capacitor is not a static load, it is a different load for each frequency. Believe me, it wasn't unicorn rainbow stuff when I was getting an electrical engineering degree.
 

Big Al

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Joined
Apr 24, 2002
Messages
14,294
Al, I'm not following you at all. A pickup is a current generating active device and is generating current at each frequency the guitar strings are vibrating. The voltages and currents coming out of it are small but they are there. A capacitor is not a static load, it is a different load for each frequency. Believe me, it wasn't unicorn rainbow stuff when I was getting an electrical engineering degree.

Excuse me, Tim. I'm going thru a rough patch and get a bit cranky. All you say is correct. How does it apply in a guitar circuit? Where does the any frequency enter or go thru the cap? As I had posted before, I got schooled about this at Whirlwind, after I made some bold claims about how much better pio caps were in my Les Paul.

The two top engineers and designers, one, Tony was from the old original MXR andthen ART before Whirlwind. I lost my bet when we tested every type of cap, precisely measured recorded and frequency plotted the results and there was no audible or measured difference between any of the caps with the same simple old digital meter.

So I end up measuring and matching hundreds of flippin' resistors and caps and handwiring the first couple of hundred Rochester Series FX pedals. I swear by everything holy, I WAS WRONG. I am relying on the real example, shown to me and the explaination given me by very acomplished audio engineers with proven, real world experience and degrees in electrical engineering,to. And like everything I have found true, some seem to look for excessively minute, hair splitting molecular differences hat have no applications to the function at hand.

So yes capacitors are complicated and fascinating components that have real and nuanced effects, in amp circuits.

So please tell me what exactly is the sonic effect in a guitar tone circuit? What exactly can be heard between a .022 pio cap and a butt simple .022 ceramic disc in a guitar tone circuit? Really, I just need to know how our ears and expensive testing equiptment failed. 'Cause I don't have a degree, I barely understand he deep science of this and rely on what my ears tell me and what my eyes see on the frequency analysers and graphs show. I also rely on the knowledge of those more learned than myself to try and get at least a basic understanding. So was I tricked into doing a boring job by smart hucksters? 'Cause I don't see where signal goes through the cap and I could not detect any difference among any of the many different caps of all types with the exact same measured capacitence load.
 
Last edited:

gasimakos

New member
Joined
Jul 20, 2020
Messages
3
So please tell me what exactly is the sonic effect in a guitar tone circuit? What exactly can be heard between a .022 pio cap and a butt simple .022 ceramic disc in a guitar tone circuit? Really, I just need to know how our ears and expensive testing equiptment failed. 'Cause I don't have a degree, I barely understand he deep science of this and rely on what my ears tell me and what my eyes see on the frequency analysers and graphs show. I also rely on the knowledge of those more learned than myself to try and get at least a basic understanding. So was I tricked into doing a boring job by smart hucksters? 'Cause I don't see where signal goes through the cap and I could not detect any difference among any of the many different caps of all types with the exact same measured capacitence load.

Sorry I'm butting in on your conversation, but would microphonics be another factor that might impact sound quality? I have no expertise in this area, but I believe the ceramic discs you mentioned, for example, are typically very microphonic. I almost wonder if some of these older PIO caps have not only drifted, but also become microphonic. You could even test it by putting them into an amp circuit and tapping on them. Wouldn't work in a guitar with unpotted pups, though, because then you can tap on anything and hear it.

Personally, I've swapped the black sprague caps for Xicon after measuring them with my meter to find a near-exact value matches and I can't hear any difference. I think a lot of people might be swapping out their whole wiring harness, switching to .022 PIO caps from .047, and changing to the 50's wiring and then claiming that it was all the PIO. These experiments need a control.
 

somebodyelseuk

Active member
Joined
Jun 10, 2020
Messages
277
@Big Al...
I get it. The tone circuit redirects/syphons off/filters out/sends frequencies above X Hz to ground, while the rest of the signal carries on down the wires. Proof of the pudding being, if you cut the connection between the volume pot and tone pot, the guitar carries on working.
@gasimakos. I suspect it's due to replacing large tolerance pots for pots closer to where they should be. ie, Gibson/NE OTHER mass production guitar builder don't measure pots as they're fitting em, whereas, aftermarket harness suppliers do...
... That, and a little 'kings new clothes' syndrome.
 

Big Al

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Joined
Apr 24, 2002
Messages
14,294
Sorry I'm butting in on your conversation, but would microphonics be another factor that might impact sound quality? I have no expertise in this area, but I believe the ceramic discs you mentioned, for example, are typically very microphonic. I almost wonder if some of these older PIO caps have not only drifted, but also become microphonic. You could even test it by putting them into an amp circuit and tapping on them. Wouldn't work in a guitar with unpotted pups, though, because then you can tap on anything and hear it.

Personally, I've swapped the black sprague caps for Xicon after measuring them with my meter to find a near-exact value matches and I can't hear any difference. I think a lot of people might be swapping out their whole wiring harness, switching to .022 PIO caps from .047, and changing to the 50's wiring and then claiming that it was all the PIO. These experiments need a control.

I think in an amplifier it would, and does have an effect. The pickups microscopic voltage goes thru the pot, but not thru the cap. As it is, any load, any specfic load placed in a typical guitar circuit will have the same effect, sonicly, regardless the substance or makeup of the load.

I don't understand why something everyone can check and verify themselves, something that has been rigorously tested and demonstrated, is debated on hairsplitting details, not applicable or having an audible or measureable effect. I know enough to make an informed decision.

The only thing that matters, in this application is the load. There is no sonic reason to spend big $$$ for a tone cap in a guitars tone circuit. Not an audible one, but if you just feel better with a particular type or look, that is fine. Numbers. In this case only the measured load is important.
 

gasimakos

New member
Joined
Jul 20, 2020
Messages
3
@Big Al...
I get it. The tone circuit redirects/syphons off/filters out/sends frequencies above X Hz to ground, while the rest of the signal carries on down the wires. Proof of the pudding being, if you cut the connection between the volume pot and tone pot, the guitar carries on working.
@gasimakos. I suspect it's due to replacing large tolerance pots for pots closer to where they should be. ie, Gibson/NE OTHER mass production guitar builder don't measure pots as they're fitting em, whereas, aftermarket harness suppliers do...
... That, and a little 'kings new clothes' syndrome.

Yeah. If you're making small changes to the values of 6 different components and adjusting the wiring and wire type all at the same time, then you are going to hear some difference.

But... I find that changing hardware, adjusting your action, changing string size, changing string material/type, adjusting pickup height, and adjusting the individual screw poles all have an enormous impact in comparison with the caps.
 
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