Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups

Russian PIO tone caps

Discussion in 'Tele Home Depot' started by motor_city_tele, Sep 9, 2010.

  1. motor_city_tele

    motor_city_tele Tele-Afflicted

    Apr 25, 2005
    motor city
    Has anyone had experience with these. It seems that they are in abundance and at a decent price. I'm thinking about picking up some of the k42y-2 0.047uf "green Meanies". I am going to use them along with some 2.7k carbon composition resistors for my esquire circuitry.

    When I was a kid my siblings and I used to compete with each other as to see who's unwound capacitor would be longer. I wonder how many vintage caps were destroyed by us. - stupid kids.

    thanx - jb

  2. jkingma

    jkingma Super Moderator Staff Member

    Admin Post
    I've got a few in my box of parts. They're pretty old so I refer to them as Soviet Caps.

    I can't tell the difference between them and the 50 cent ceramic disc caps that my local electronics shop sells.

  3. LocustPlague

    LocustPlague Tele-Holic

    Sep 17, 2008
    I have still, to this day, failed to see any scientific evidence that even suggests that anyone can hear the difference between two caps of different compositions, but with the same value. Every case I've ever seen where people try to do a blind test fails due to the fact that they don't measure the caps to ensure they are the same value -- they just take the value printed on the part itself. Either that, or they fail in experimental setup.

  4. drf64

    drf64 Friend of Leo's

    Jul 24, 2009
    Ada, MI
    I haven't used them in guitars. I have used them in amps and I think they are superior to run of the mill mylar caps. But then I'm also a guy who swears by Sozos, so who knows.


  5. Wayne Alexander

    Wayne Alexander Friend of Leo's

    Last edited: Sep 10, 2010

  6. Wayne Alexander

    Wayne Alexander Friend of Leo's

    I've used them in guitars, and found that they sound pretty much like other PIO caps like the new Jensens, cost less, and are a bit smaller. I usually like the sound of PIO caps in guitar tone circuits better than the sound of polyester or polystyrene or ceramic caps, and despite some naysayers here, I can hear the tonal difference in cap composition between caps of the same measured value, as can a lot of other people. You'll notice this less if you don't use the tone controls on your guitar, and you'll hear the biggest influence from the tone cap with the tone control cranked most of the way to the bassiest position. It doesn't cost much to experiment with this.

  7. tangelolemon

    tangelolemon Tele-Meister

    Dec 19, 2009
    Brooklyn, NY
    I've never seen any scientific evidence proving that Albert King is good, either. But I like the way he sounds, so I listen to him.

  8. LocustPlague

    LocustPlague Tele-Holic

    Sep 17, 2008
    One could actually experimentally prove that Albert King is good by organizing and conducting an experiment. This would be science. How well the experiment is organized (proper sample of people, questions properly formed, etc) would decide whether it is good or bad science.

    I have yet to see a single double-blind test in which the listener uses two caps of the same measured value and can detect the difference and specify which cap is in which position. Furthermore, when people describe the effect the caps have on tone, they describe them in terms of frequency response. "Scooped mids", "defined high end" "warm" "ice-pick" etc. etc. and forever are all frequency response terms or terms that are used in the place of technical frequency response terms. They have meaning electrically and describe something that you would be able to see if you charted frequency response -- however, when the different capacitors are put to this kind of test, there is no discernible difference in frequency response.

    Imagine if I told you that one glass of milk was warmer than another glass of milk...yet you put a thermometer to them and found they were at identical temperatures. Sure, I could continue to claim that the glass on the left is warmer, but the only guy I would be fooling is myself.

  9. chillman

    chillman Tele-Afflicted

    Dec 6, 2009
    I have one of those caps in El Cabron, and the guitar sounds amazing, but I can't exactly prove that those two things are related.

  10. motor_city_tele

    motor_city_tele Tele-Afflicted

    Apr 25, 2005
    motor city
    Thanks - I will pull the string on the deal and use them in my circuits. I just didn't want to install 30 caps and have them be junk. I am trying to keep the technology as similar to that used during the time period.

  11. middy

    middy Friend of Leo's

    Apr 28, 2010
    Dallas, TX
    Guitar tone geeks. Making EEs giggle since 1990.

  12. tangelolemon

    tangelolemon Tele-Meister

    Dec 19, 2009
    Brooklyn, NY
    "Absence of evidence is not evidence of absence" --Carl Sagan

  13. Doubletriode

    Doubletriode Tele-Meister

    Mar 23, 2008
    First let me say that I am not an expert in electronics, I have mounted a few kits, including tube amps, and installed more pickups and guitar wirings that I can remember.

    If my understanding is correct, the only function of tone caps in guitar circuits is to subtract high frequencies by putting them to ground.

    Technically speaking, they are NOT (!!!) in the signal path since the sound we hear is made of the frequencies that have NOT been put to ground.
    So... :confused:

    I like to have PIO caps in my guitars because I like vintage stuff for aesthetic reasons but, frankly, I doubt they make any difference in sound.

    Anyway, like Ron Kirn says (I know he will correct me if I misquote him :oops:) whatever makes you feel better is good because it makes you play better. So, if somebody thinks PIO or snake oil sounds better there is no point discussing it.

  14. tangelolemon

    tangelolemon Tele-Meister

    Dec 19, 2009
    Brooklyn, NY
    At the risk of having that discussion again :)razz:) I might just be starting it. I'm not going to try to argue in favor of or against the presence or absence of any phenomenon. However, I feel that what you've presented here represents an incomplete description of the situation with guitar tone controls.

    First of all, and fundamentally, it's good to state up front that "what you start with" minus "what you take away" equals "what you have left." So the fact that we're dealing with a subtractive circuit is of little consequence. In fact, when dealing with time domain as we are when discussing non phase-linear filters of any kind, I'd expand it to say "what you start with" minus "what you take away... and when..." equals "what you have left... and when."


    Now to discuss what I feel is missing from your analysis-- missing from the "schematic," first of all, is the inductance contributed by the pickup coils. This inductance coupled with the capacitor and the potentiometer form an LCR circuit which is capable of resonating at certain frequencies, depending upon the values of the reactive components (inductor, capacitor).

    Also missing from the "schematic" in the real world (i.e., not using an idealized theoretical model of a "perfect" capacitor) are inductance and resistance inherent in the capacitor itself.

    In practice, inside your capacitor there is not only a capacitor, but also at the very least an inductor and a resistor (called equivalent series resistance). In many cases, there is also a microphone capsule (remember that capacitors can be microphonic-- in fact, a condenser microphone capsule is nothing more than a capacitor specifically designed to be as microphonic as possible).

    Additionally, a real-life capacitor will have other "anomalies" such as dielectric absorption and susceptibility to temperature and humidity induced non-linearities.

    While the measured capacitance in farads might be the same from one make or style of capacitor to another, these other properties most certainly will NOT be. Many capacitors in the modern era are specifically designed to have as little inductance as possible. Among these are your high-end "audiophile" caps like Hovlands, etc., which tend to brag about their low inductance. Other capacitors (especially those types which are essentially rolls [ahem coils] of metal foil separated by dielectric) can have higher inductances.

    As for ESR, some capacitors use metallized plastic, some use aluminum foil, some high-end makes even use copper foil or even silver foil in extreme high-end cases. I would imagine the different conductive properties of these materials would have an impact on the ESR. But you don't have to take my word for it. Let's go to the data sheets! I borrowed some of the following from a post I made on another forum a year or so ago.

    Here's some interesting data from Sprague/Vishay's own documents. Emphasis is mine.

    There's more, too, including a descriptions about time constants as related to dielectric insulation resistance, which itself is a function of "the property and quality of the dielectric material."

    Also, there are graphical representations of the following across Sprague's line:

    • Capacitance change versus temperature
    • Capacitance change versus frequency
    • Dissipation factor versus temperature
    • Dissipation factor versus frequency
    • Time constanct versus temperature

    The graphs show significant differences in all between capacitors in Sprague's own line.

    I am in favor of rational thinking and healthy skepticism, and I do agree there is a fair of disingenuous marketing out there, but I think there's enough empirical evidence to at least suggest that there might be something to this whole capacitor thing.

    It has always been my opinion that SCIENCE and THEORY both exist to explain observed phenomena-- not to tell people WHAT they are allowed to observe.

    If I observe something that can't yet be proved scientifically, then that doesn't cause me to question whether or not I've observed it. It causes me to question the degree to which we fallible humans really understand what we think there is to understand. I feel that is putting the cart and the horse in the correct order.

    "All that we know" is not the same as "all that there is to know."

  15. Doubletriode

    Doubletriode Tele-Meister

    Mar 23, 2008
    you are certainly an expert :D

    I had to read your post two or three times to understand it :D
    as a matter of fact, in the end I agree with everything you said

    what I would question, considering the HUGE complexity of the factors involved and of their INTERACTIONS, is the possibility to say that in every situation, whatever the pickups and the circuitry, PIO or ceramic or polyester film etc. sounds better...

    not to mention cables, effects, amps and THE PLAYER... :lol:

  16. Tracer

    Tracer TDPRI Member

    Jul 31, 2010
    Albuquerque, NM USA
    I’ve been looking into this guitar tone cap issue and if there is one thing that looks to have merit, it is the non-linear properties of the dialectics. These non-linearities are real and will create distortion. Whether this distortion is audible is another question. I recently found this series of articles that covers capacitor distortion in brain-numbing detail.

    There appears to be reason to suspect audible distortion from high-K ceramic caps. Though there appear to be very good ceramic caps. Not all ceramic caps are the same. The author ultimately recommends polystyrene caps (not that common). Unfortunately aside from a brief mention of PIO caps, he did not test any.

    For the non-electrical engineers reading this stuff, keep in mind that everything in electronics has to be considered in context. Too many times the layman, reads something about a circuit in one application that simply doesn’t apply in another. For example, there’s a big difference in what matters for a power supply filter capacitor versus a capacitor in the signal path.

    By the way, a guitar tone capacitor is very much in the signal path. It is in parallel, not series, but it is every bit as much in the signal path. If, for some reason, you are unwilling to accept that a parallel component is in the circuit path, parallel circuits can be easily converted to series equivalent circuits for analysis purposes (look up Thevenin and Norton equivalent circuits) .

    Something else for the skeptical engineers to consider, before dismissing the capacitor sound as being in the heads of cork sniffers, is that the guitar circuit is a very high-impedance circuit. I’m hard pressed to think of any circuit that is commonly this high. As a result, many things that would be truly insignificant for a lower-impedance circuit can play a role in guitar circuits. An example is the guitar cord. Given the high-impedance of the circuit, the pico-farads of cord capacitance can effect the signal. Of course it depends on the guitar, amp input characteristics, and length of cord.

  17. tangelolemon

    tangelolemon Tele-Meister

    Dec 19, 2009
    Brooklyn, NY

    Not an expert! A nerdy hack who loves electronics and guitars and goes through phases of thinking and reading about this stuff. :D

    Like I said, I wouldn't make any claims necessarily, as I haven't done any experiments. I just believe in not shutting myself off from possibilities.

    I wholeheartedly agree that it wouldn't be possible to predict that one or the other would behave "better" in a given situation due to the variables you listed... and most importantly the variable of personal preference/taste!

    It's also possible (indeed probable) that at least some of the factors/variables wouldn't matter much at audio frequencies. I do know that some very demanding operations--where accuracy at very high frequencies (on the order of megahertz) is essential--can require very high-quality capacitors. But at audio frequencies? who knows.

    Not everyone hears the same, either. There are varying levels of perception there, which is another variable.

    And the psychological effect, etc. I think the reason this hasn't been explored more experimentally is that it would be very hard to disprove anything.

    A truly conclusive listening test would have to account for a staggering number of variables. Otherwise you'd have people saying "well, I could hear it on my amp" or "on my guitar" or "when I was playing," or "when I wasn't expecting to hear it" or "when the atmospheric pressure was different" or "in an anechoic chamber" or "in a concert hall" etc etc etc. Even if all those variables were accounted for, you'd only be able to prove the sample could/couldn't hear it--unless you tested the entire world's population.

    Some form of electronic "null test" could theoretically be devised, but it seems like that would require finding two preamplifying devices and analog-to-digital converters that would produce a complete and perfect null. And even then you'd have people claiming that "no human could hear" whatever difference was evident, and debate as to whether the discrepancies were or were not "within the noise."

    So I kind of content myself to just say "hmm... if a large number of people claim to observe a phenomenon, then--taking them at their word--what could possibly cause that?" If I come up with something plausible enough, I usually just give them the benefit of the doubt.

    We would also probably agree that none of this is likely "important" enough to merit the amount of pixels we and others have spilled on it over the years. Try a guitar. Like the way it sounds? Good, go make some music. Feel like trying to 'trick it out?' be my guest. :D

  18. LocustPlague

    LocustPlague Tele-Holic

    Sep 17, 2008
    My primary complaint with the situation is that most people describe the difference in terms of frequency response when there is absolutely no difference to be measured. Surely anything that can be observed can also be described.

    I have no problems with people doing things just because they feel good about it. The first guitar body that I built was a 3 piece sandwich. I actually embedded a sheet of paper that I had written on throughout the planning/building stages between two of the slices in the sandwich. Does it make a tonal difference? I seriously doubt it...does it make the guitar feel more "mine"? Hell yes.

  19. deaconque

    deaconque Tele-Meister

    Feb 8, 2009
    Regardless of the scientific evidence against cap difference, I can say that I can definitely hear a difference. My simple test to evaluate caps was to attach alligator clips in place of the cap in a guitar. I got a collection of various types of caps and put each one in the alligator clips to hear the difference. It may not be the most scientific of methods but it worked for me. I could hear a substantial difference between say ceramic and orange drops or mylar and PIO. My $.02

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