The Truth about Tone Capacitors

Discussion in 'Tonefreaks' started by Rodolphe, Dec 4, 2013.

  1. woolenmammoth

    woolenmammoth Senior Member

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    Sure. I own a small company which designs and manufacturers amplifiers. Prior to that my primary job was recording engineer and did service work on the side. My education came from maintaining and repairing studio equipment which was a "by ear" rather than "by calculus" affair.

    Keeping up with some consoles is somewhat like painting a bridge where when you finish painting one side you start right over at the other side because its started to rust. Some consoles generate so much heat that by the time youve finished capping it, you start back over, its a constant job on some designs which are imo abysmal because of that. Sometimes in the middle of sessions channels fail and need fixing. Sometimes the caps you have on hand to do an immediate repair may have the exact value and rating but are different that the channels next to it and when you put the channel back in the board you get an engineer, an assistant, a producer all telling you it sounds different to the point that you pull the channel and put it at the other end of the bucket because it wont work in stereo because of the caps you put in it, which were the exact value that ya took out. Works fine, measures to spec, just sounds different. How different? Eh, different enough that your stereo image is wack with closely matched mics. You go through this exercise a few times in your life and you'll never have a conversation like this again...

    What really piqued my interest in this years ago was prototyping an EQ with a decade that had pet caps in it, then putting in polypros once we built the board and measuring a different frequency response as well as different corner freqs. put in pet's that we had on hand which matched what was in the decade and magic, back to what we had before.

    Whats funny is that in our professional circles we never have these debates. People will talk a bunch of drunken shit at a trade show and not once in my life have I heard another manufacturer be dismissive about capacitors beyond poking fun at the hifi crowd.

    The amount of user evidence out there is staggering. You can look at professional recording forums and read threads about why does new gear X not sound like old gear X. As surface mount becomes more and more of an unescapable reality for manufacturers, users now sit and ask why the new small signal amp in brand x sounds different than the old one, and not the old one from the 60's. The old one from 2001. In some cases the answer is simply because the type of cap that is available for coupling in some surface mount designs today are all ceramic. And no matter how good COG is, it is never, ever going to sound like the old (old meaning what you could buy 5 years ago) film caps that are not available in surface mount. These are recording guys whose only job is to listen and they arent tech's at all. They dont know about caps and mostly dont pretend to either, they just know they had a ten year old amp in their console fail, got a replacement from the manufacturer and now the thing sounds different. And its the same exact amp, made from the same drawing, fabricated by the same board house that has been doing the work for ages. The only difference is the new amp is surface mount construction where the old one was through hole and the component selection is different because of that. same transistors spec'd to the same hfe, similar enough layout, only thing is different is the caps, theyd been using metal film resistors for years.

    I can go on an on... We dont sit around and wonder if caps sound different. We dont sit around and hear a difference and then "dont trust our ears" and second guess the universe. We sit around trying to identify what made the old gear that everyone is fiending after sound the way it does and do our best to make new designs that satisfy the expectation of engineers who use all this old stuff. If caps didnt have an inherent sound 1. any half idiot could make good sounding gear and ALL the cheap stuff that gets made overseas using the cheapest components possible to save money would ALL sound exactly the same as the high end designs they have cloned and 2. we would save literally hundreds of man hours a year by being blessed with the opportunity to open a distributors catalog, randomly pick any one of the hundreds of different ".01uf/250v" cap that comes up in a search, put it in the circuit and know it will work and sound the same, because caps apparently have no sound. This is not how it works.

    Anyway, this is an absurd depth to go to to suggest to people that it is worth some time to listen to a cap in a guitar. I have no horse in this race, its your guitar, your tone, your world. I like coming on here to learn about les pauls because it's my preferred instrument and this message board is an excellent barometer to judge the failures and success of gibson's marketing which is insightful for what we do now. Coming from a world of recording guys, which is a world of listeners (not to instruction from the internet, but to sound coming out of speakers) its odd to make a suggestion to hey dude, clip some leads in your guitar and have a listen to then be brought to task by prove it to me guy. Try it, dont try it, who cares. Watching people discourage others from even listening out of curiosity is just an odd thing and why I post this crap. Maybe all the caps you "tested" sound the same. I know I have been in that boat time and again. Its a lot easier to find 10 caps that sound the same than 4 that sound different. Also please consider, Im not trying to convince people of a single thing. Seems like the people that have their mind made up should get a high five, it's for everyone else who's on the fence. Have a listen. You might find something you like better than the disc cap in your guitar. you might not either but at least you discovered for yourself and didnt have to take my or some other guy's word for it.
     
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  2. FourT6and2

    FourT6and2 Senior Member

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    Noted. Thanks for clarifying. :)

    I'm curious why a company would make three different kinds in the first place, then. Why bother making a copper foil, PIO cap in ceramic, copper, and aluminum casing? In what situations would someone need or desire one over the others? Off topic, I know. But the door has been opened. :) I'm not trying to imply there is an audible difference between them. I'm just curious.
     
  3. KenG

    KenG Senior Member

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    The reason for different dielectrics is varied. Ceramics are small, inexpensive and a strong dielectric for voltage but have a limited range of capacitance.
    Tantalum caps offer small size, fairly large capacitance for filtering but a lower voltage range.
    Environmental, size, stability and voltage ratings can all call for different cap construction. Consider though that the entire audio band of 20Hz - 20KHz is but a small insignificant fraction of the working frequencies caps actually operate at (DC - GHz).
     
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  4. matt@msscguitar

    matt@msscguitar www.MSSCGuitar.com Premium Member MLP Vendor V.I.P. Member

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    All of this is a bunch of perceived mathematical, scientific masturbation.

    In all seriousness, I could personally give two shits of whether something can be proven with a calculator when it comes to sound. I'm all about what my ears like.
     
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  5. Quill

    Quill Senior Member

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    I'm in no way trying to highlight any part of your great post, wm - just catching a couple of phrases. All I want to say is,

    Best response ever.
     
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  6. El Kabong

    El Kabong Senior Member

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    My bad... it appeared to me that you were pointing at two apples and asking which was most like an orange... I've never tested Jensen foils but will certainly give them a listen... my guess is that while they might be the best of what the new generation of caps has to offer, they won't compare to traditional paper in oil for the classic PAF based sound (if there is such a thing) I'm in pursuit of. Of course I won't know until I hear them as specs mean very little to me as far as caps go.
     
  7. El Kabong

    El Kabong Senior Member

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    I'd like to know which specific myths you are referring to... my father and brother are both electrical engineers (60+ and 40+ years) and they both told me the exact same thing... "caps distort sound and different caps distort sound differently..." how much differently is subjective but the fact that they are indeed scientifically and audibly different seems to me to be the "truth about tone capacitors".
     
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  8. FourT6and2

    FourT6and2 Senior Member

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    I think you misunderstood. I am not referring to the dielectric. I am referring to the casing. Jensen makes copper foil aluminum tube, copper foil ceramic tube, and copper foil copper tube. All with the same dielectric. My question was why. There must be a different application in mind for each, otherwise... why would Jensen bother?
     
  9. SteveGangi

    SteveGangi V.I.P. Member

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    Yup, it's the tolerance. Some are right on, some are a little off but still within acceptable limits, and some are junk. Good QA practices and inspection sampling will weed out the bad ones.
     
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  10. KenG

    KenG Senior Member

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    Distortion is a pretty broad term & can refer to any change from the original signal. What exactly are they claiming using this generic term?

    Electronics is a science not mumbojumbo and I've yet to see a real scientific study of how different caps respond across the audio band in any post. People continue to clutter the "tes circuit" with other reactive components blurring the results.
     
  11. El Kabong

    El Kabong Senior Member

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    For an understanding of how caps work I don't think the term distortion is all that broad. At least it shouldn't be. It is perhaps easiest to clearly understand visually... if you look at soundwaves through an oscilloscope and/or spectrum analyzer you can see a loss in clarity as the sound goes out of its natural range. Any deviation from that norm is considered distortion. While it can take many forms, all of them are distortions of sound.

    For anyone interested, there is an online course being offered by the Berklee College of Music on an Introduction to Music Production and one at the University of Rochester on the Fundamentals of Audio and Music Engineering (contact me if you want details on auditing these courses for free) which discuss the properties of sound and distortion in much greater detail.
     
  12. KenG

    KenG Senior Member

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    If you're looking at sound waves on a scope you won't get clarity. Oscilloscopes have a simple amplifier that tracks the sum of all signals present at any given moment in time showing them as a single trace. They cannot separate content by it's location in the spectrum. Anyone who uses a scope knows this or should.

    I think discussing active mixing & amplifying is an entirely different can of worms than passive caps in a passive circuit.
     
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  13. gtr-tek

    gtr-tek Fumble Fingers

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    My $.02 on several of the subjects here:

    Component burn in - I worked at an electro-medical manufacturing facility performing calibration, testing and burn-in on therapeutic ultrasound equipment. I would calibrate the new machines and put them in a rack to run a burn-in algorithm on them for 12 hours. 99% of the machines drifted during this process. I would then re-calibrate the machines and send them to QC for final testing and calibration. This has no bearing on a guitar circuit of course as the voltage is so small as to not even heat up the circuit.

    Composition of capacitor vs tone - I do hear the subtle differences on the effect of different caps in a tone circuit on a guitar. I hear it most when the guitar is wired '50s style. I prefer PIOs with humbuckers. Just my opinion.

    Voltage value of a tone cap - bigger isn't necessarily better. Nor is it worse. 400v caps were used in the '50s and early '60s as that is what was readily available in the values requested. If they were out of 400v caps, 600v could be substituted without making a hill of beans difference.

    I remember in the early '80s the tube was almost declared dead. Solid state amps were coming out and we thought they would eventually take over. They did, for the most part in the hi-fi world with a few notable exceptions. Ten years later and the tube is back with a vengeance. They just sound more pleasing with guitars. Tape is a similar thing as is vinyl. For some things, analog just sounds more pleasing. :hmm:
     
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  14. KenG

    KenG Senior Member

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    I think the transistor revolution started in the 70's actually and yes NA tube facilities literally shut down. Transistors at the time couldn't give the harmonic distortion tube do. But the difference in this case is it is a documented, well understood, scienctific fact that is verifiable with modern measurment procedures and equipment.
    A lot of people champion tape recording but tape degrades continually so the master would sound great initially but it wouldn't stay that way once played a few times.

    Current signal processing and digitization has come leaps and bounds and I find it funny that people can listen to and enjoy CD/DVD audio quality totally ignorant of or just refusing to admit that what they are listening to is Digitized Audio.
     
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  15. gtr-tek

    gtr-tek Fumble Fingers

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    True on all counts! The SS amps came out in the mid to late '70s but we thought they would continue to get better as we went along. It seems to me that the early to mid '80s is when we thought the tube was actually dead. RCA quit making them and closed their doors in 1986 as televisions didn't need them anymore and guitar amplifiers weren't a big enough market to sustain them. Their broadcast equipment went out with the company for the most part. Solid state guitar amps hit the wall as the distortion was nasty and didn't overcome the harmonic tendencies inherent in their design. By the late '80s and early '90s, the tube made the big comeback. There are a number of hybrids as well but they fall just short in my opinion. Not bad, but at high volume and gain still lack the proper "hair" and "sag" of tubes. The modeling amps fall into this category as well but are still pretty good.

    My favorite recordings are ADD which have the benefit of nice sounding analog main tracks and then preserved digitally throughout the rest of the process. :dude:
     
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  16. martin H

    martin H Senior Member

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    I agree. I spent much of the 70's and early 80's very interetsted in what was called "Hi fi" sound in those days, and reading many of the monthly magazines dedicated to the subject. . IMO, as equipment got better and better, it became harder and harder to make measurable technical assesments of each new piece of equipment. This made neither manufacturers, nor Hi-Fi reviewers particularly happy.

    Consequently the reviews began to rely much more on the "golden ears" of the reviewer, and a largely subjective view of the "openness" of the sound, the "depth" of the soundstage, the "detail" revealed, etc etc (and probably whether the sound contined notes of cherry and oak as oppossed to plum and zinc).

    The problem to me was that there was no objective standard for these new paramaters or methods of measurement. What was essentially a measurable technical difference has been converted almost into a Guru and servant relationship, in which each listener chose who to follow in order to negotiate these new, almost mystical paramaters of evaluation.

    This, in turn, led to the $200 power cord, the gold plated $400 RCA lead, the handmade $5,000 phono cartridge enclosed in an old growth teak housing, and many other expensive things too numerous to mention. Each of these gizmos has a following that insists that the component provides an improvement in sound that they can hear.

    This belief is entiely subjective, and no doubt sincerely held. However, I belive it is also often driven by situational factors. I spent 30 years in electronics service before going into law, and ran a small studio for 10 years, and I would observe the following.

    1. I never observed anyone who has a modification done for "tone" purposes (different brand of tube, new tubes, new transformer, new input cap, new speaker new bridge, new nut, new tailpiece, new pots etc) who didn't think things sounded better immediatly after the modification. Often the shine would fade after a few weeks, and the same guy would be back asking me to either restore the previous configuartion or try yet another mod.

    2. 90% of complaints about the "tone" of an intrument in the mix could be solved just by making it louder, at which point the "tone" was much improved

    3. to 95% of musicians , the loudest master has the best overall sound. Things sound "punchier" "stronger" "deeper"

    3. if you tell someone you've changed the tome of a track, they can usually hear the change , even if there wasn't one ( I didnt do this deliberatly, but did notice the effect when I accidently sent out an older mix)

    I'm not denying that there are changes in sound that are perceivable but difficult to effectively measure. However, to me "I can hear it" does not necessarily evidence that something objectively exists.
     
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  17. El Kabong

    El Kabong Senior Member

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    This sounds about right. Perception seems to be the key, and different people perceive things differently. Its like measuring the degree/intensity of a smile. If a stunningly beautiful girl smiles at you, what exactly does that smile mean? Does it mean she's into you? She's being polite? She thinks you are me? She has gas? Some more desperate guys will notice the tiniest little almost imperceptible crease around her eyes and take that as a blanket invitation. Or pick up on some kind of ESP with no measurable distinction at all. Again, perception is the key, and right or wrong, different people perceive things differently. Kind of explains all the problems in the world today... its all due to the damn caps! :naughty:
     
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  18. FourT6and2

    FourT6and2 Senior Member

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    I've done this a few times. Installed a Motor City Afwayu pickup. Immediately hated it. Installed an RS Guitarworks wiring kit (new pots, new caps). Immediately hated it. I've also installed tubes (both power and pre) of various kinds in various amps and immediately disliked the difference in sound.

    Pickups are a huge difference, though. Easy to hear. Caps? Not so much. Even tubes present a large difference if you're jumping between tube types. For example, I recently switched from EL34 to KT77 in my amp and noticed a very large difference. Much more so than switching between brands of EL34 (like from JJ to SED).

    But I understand what you're getting at. That any difference, whether good or bad (or not even a difference at all) can be perceived as being a positive change just because it is a change.
     
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  19. ARandall

    ARandall Senior Member

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    I've made changes I didn't like...plenty of times. New magnets in pickups, pickups made from coils of different models, a tube swap around, some pots or caps and often the wiring scheme. I'm now much more adept at soldering and taking apart pickups than I ever imagined possible
     
  20. Brocko

    Brocko Senior Member

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    Personally i have never noticed any difference - someone defended the pricier ones using the perception argument (i.e. i think it makes a difference so it does). If that is true, then the reverse is true - believing that a 60p cap from your local electronics store will sound just as good as a £100 boutique PIO cap! You can save all that money and spend it stuff that does actually affect your sound!
     
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