Whitmore Willy Posted June 14, 2011 Share Posted June 14, 2011 Title says it all. Someone (not me) went through a lot of trouble. Thought some of you might be interested. (read last paragraph for samples): http://www.kernelofwisdom.com/02-10/shootout2.html Original post with opinions from others: http://www.mylespaul.com/forums/tonefreaks/111027-new-capacitor-shoot-out.html Willy I meant to put this in the Epi Lounge...Oh well. If one of the mods wants to move it...fine by me. Link to comment Share on other sites More sharing options...
RaSTuS Posted June 14, 2011 Share Posted June 14, 2011 Good links, thanks Willy. Link to comment Share on other sites More sharing options...
fenson Posted June 14, 2011 Share Posted June 14, 2011 IMO this fellow does a great job explaining the whole deal . Link to comment Share on other sites More sharing options...
RaSTuS Posted June 14, 2011 Share Posted June 14, 2011 IMO this fellow does a great job explaining the whole deal . These have been listed before, about 3 or 4 months back, but may be useful to those that missed that post. Link to comment Share on other sites More sharing options...
Dougefresh91 Posted June 14, 2011 Share Posted June 14, 2011 My head actually exploded after reading that. OK, I lied, I just skimmed. I bought parts for a treble bleed a month or so back, and I have yet to actually get it done. Kind of forgot about that until now, actually. Link to comment Share on other sites More sharing options...
Lefty Bill Posted June 14, 2011 Share Posted June 14, 2011 Title says it all. Someone (not me) went through a lot of trouble. Thought some of you might be interested. (read last paragraph for samples): http://www.kernelofwisdom.com/02-10/shootout2.html Original post with opinions from others: http://www.mylespaul.com/forums/tonefreaks/111027-new-capacitor-shoot-out.html Willy I meant to put this in the Epi Lounge...Oh well. If one of the mods wants to move it...fine by me. This has likely been mentioned before, but this author/expert presents some interesting data regarding capacitance and other factors http://buildyourguitar.com/resources/lemme/ Another in-depth approach by a physics professor, although the link may be shortened.. the Goog search was: guitar electric pickup resistance. online.physics.uiuc.edu/.../electric_guitar_pickup_measurements.pdf I've ordered some multi-position switches to try some 5-cap tests for myself. I think the well-intentioned guys that are stringing loose wires to capacitors for testing are likely to be getting inaccurate and/or inconsistent results. Different capacitor types are going to have slightly different dielectric absorbption characteristics, which will likely also have an influence on the changes in a guitar's output signal. The caps I see various sellers offering are often rated for 400 volts, which is far beyond (X10+) a reasonable rating for guitar output signals.. 100V ratings would be overkill, but 50V ratings are commonly available. Regards, Bill Link to comment Share on other sites More sharing options...
RaSTuS Posted June 14, 2011 Share Posted June 14, 2011 The caps I see various sellers offering are often rated for 400 volts, which is far beyond (X10+) a reasonable rating for guitar output signals.. 100V ratings would be overkill, but 50V ratings are commonly available. I've noticed that sometimes I get 100V and other times get 400V when buying them online, what effect does the different voltage ratings have Bill ??? Link to comment Share on other sites More sharing options...
Whitmore Willy Posted June 14, 2011 Author Share Posted June 14, 2011 Another in-depth approach by a physics professor, I've ordered some multi-position switches to try some 5-cap tests for myself. I think the well-intentioned guys that are stringing loose wires to capacitors for testing are likely to be getting inaccurate and/or inconsistent results. Different capacitor types are going to have slightly different dielectric absorbption characteristics, which will likely also have an influence on the changes in a guitar's output signal. Bill, Interesting article. As you seem well versed on the subject, do you think the voltage (i.e. the amount of dialectic material) has an effect on the dialectic absorption characteristics? Not being a wise guy! The reason I ask is that I have taught myself guitar electronics. Although I understand the physics, it is not what I use to evaluate guitar electronics. In other words, I'm a hack and this is my idea of testing caps: After that, I tell you what I hear....which isn't much. To me, guitar electronics is a small link between a musician and an audience. For me, it is a utility for fine tuning one item in a very long chain. Now here's the rub: Even though I don't hear a lot of difference, I find evidence it is there. My wife is extremely sensitive to high frequencies. In blind test, she is able to pick out the PIO cap (as opposed to others) in test after test. This proves nothing. I don't hear it!....I do believe it exists and that others do. Willy Link to comment Share on other sites More sharing options...
Bookkeeper's Son Posted June 14, 2011 Share Posted June 14, 2011 My dog can tell the difference, but there's that opposable thumb thing again......... Link to comment Share on other sites More sharing options...
Whitmore Willy Posted June 15, 2011 Author Share Posted June 15, 2011 My dog can tell the difference, but there's that opposable thumb thing again......... Your dog has opposing thumbs? How cool! Willy Link to comment Share on other sites More sharing options...
Lefty Bill Posted June 17, 2011 Share Posted June 17, 2011 I've noticed that sometimes I get 100V and other times get 400V when buying them online, what effect does the different voltage ratings have Bill ??? The output signals of electric guitars are typically in the millivolts to a couple of volts range, and the tone capacitors required voltage ratings are very minimal. When a 10V rating would be adequate, most manufacturers will install any voltage rating they get a good deal on, or already purchase for other uses. The circuit effects of a 10V and a 400V film capacitor should be about the same, but only if the same manufacturing practices and materials are the same. The voltage ratings are for establishing a safe working voltage limit for a particular capacitor. I've got some small brightly colored 2kV caps, but there's really no worthwhile purpose in installing them in a guitar's tone circuit (they're for TV horizontal circuits). Regards, Bill Link to comment Share on other sites More sharing options...
Lefty Bill Posted June 17, 2011 Share Posted June 17, 2011 Bill, Interesting article. As you seem well versed on the subject, do you think the voltage (i.e. the amount of dialectic material) has an effect on the dialectic absorption characteristics? Not being a wise guy! The reason I ask is that I have taught myself guitar electronics. Although I understand the physics, it is not what I use to evaluate guitar electronics. In other words, I'm a hack and this is my idea of testing caps: After that, I tell you what I hear....which isn't much. To me, guitar electronics is a small link between a musician and an audience. For me, it is a utility for fine tuning one item in a very long chain. Even though I don't hear a lot of difference, I find evidence it is there. My wife is extremely sensitive to high frequencies. In blind test, she is able to pick out the PIO cap (as opposed to others) in test after test. This proves nothing. I don't hear it!....I do believe it exists and that others do. Willy The dielectric absorption properties of capacitors (and other characteristics) essentially determine how effectively the capacitor performs while charging and discharging. I mentioned the DA issue because I didn't notice that the folks doing the evaluations had actually tested the capacitors they were using, before performing the tests. Most multimeters won't show any indication of internal faults.. instead, a dedicated analyzer or test circuit are generally required to display worthwhile test information. The dielectric absorption will differ with the amount and type of dielectric, although capacitor manufacturers take these factors into consideration when selecting materials and manufacturing processes. You're using a very reasonable setup for evaluating cap changes, Willy, IMO. Keeping the test leads short, and a neat layout in the controls cavity will minimize additional stray capacitance. I agree, the tone caps are a small part of a long chain of factors involved in a typical electric guitar setup. FWIW: The common vinyl-jacketed shielded cable of some newer Epiphone pickups is about 120pF/foot. The pickup insulating parts/bobbins introduce additional capacitance between the coils and the pickup frame (ground). An Epiphone 57CH (57CH plus, bridge pickup) I measured showed about 12pF per coil, to the frame plate. Insulated wires in contact with the other metal parts or other wires in the control cavity will affect the capacitance value of the tone cap(s). The short shielded cable from the controls to the output jack will add another small amount of capacitance. Guitar output cables also exhibit capacitance. Changing guitar-to-amp cable lengths (or type of cable) changes the characteristics of the signal entering the amp. Some random examples, a good quality 10 foot cable with Switchcraft plugs measures 350pF. A 12 inch jumper cable with molded 90 degree plastic plugs measures 55pF. As capacitance values are combined in parallel, they add. In control cavities which are laid out neatly, with no excess wire lengths, one can reasonably expect that the selected tone caps are actually doing what they're intended to do, a somewhat predictable roll-off of specific frequencies. Regards, Bill Link to comment Share on other sites More sharing options...
Whitmore Willy Posted June 17, 2011 Author Share Posted June 17, 2011 Bill, It is a rare few that have both the mathematical understanding of electronics and the ability to explain it in layman's terms. Thanks for taking the time. Hope you stick with the forum. Willy Link to comment Share on other sites More sharing options...
BlueEpiphone Posted June 17, 2011 Share Posted June 17, 2011 Bill, It is a rare few that have both the mathematical understanding of electronics and the ability to explain it in layman's terms. Thanks for taking the time. Hope you stick with the forum. Willy Agreed...and two opposable thumbs-up for the neat wiring in that control cavity pic. Link to comment Share on other sites More sharing options...
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