the tone cap myth...

[Possum]

...

Mike, I wasn't trying to be mean, but your outright dismissal of my sound clips as irrelevant without any experience of your own in this matter wasn't taken well here :-)

I think it is possibly true that a handmade humbucker may be more sensitive to this cap value switching. Especially this set I make, which is based on actual PAF technology from that era. I make my own magnetic circuit parts and they aren't like anything any of the factory parts makers or factory pickup makers use. These pickups are real touchy about what magnets are in them, whereas if I use the factory parts that everyone here uses, the magnets don't have such a big effect, so maybe these are more prone to a cap value change.

SK's plots at least prove that cap TYPE does change the audio signal, maybe its not easily heard, but put it in the context of someone playing stadium rock with a bank of big ass amps behind them; every tiny thing becomes magnified. I supposed there is such a thing as tone cap snobbery out there, but if there was really nothing to this at all, I don't think there would be a raging business community selling NOS tone caps out there, things and ideas of no substance usually fade away for good.

I'm glad you're going to give this a try, you could also use a frequency analyzer to plot results, you can get free software for a PC that does this stuff, it doesn't have to be perfectly accurate, just repeatable, whatever method you use.

I got those Sprague NOS caps in yesterday and am going to swap them for same value singlecoil.com caps and see if I hear any difference. I don't expect to but remain open minded....

[Mike Sulzer]

Mike:

You keep insisting that the series resistance of a 250k to 500k tone pot wired as a variable resistor is "huge"- so large that the value and characteristics of the capacitor becomes insignificant.

With a pot wired as a 3 terminal potentiometer, it is the resistance to ground that reduces the signal level, not the series resistance. When you add in the third connection (to ground) you then have a voltage divider of sorts.


You have also suggested that you would not hear the difference between caps of different values if the tone control was set to 0.

Yes, the series resistance is large, and guitar tone controls use the the pot as a variable series resistor. As a three terminal pot, the series and shunt resistance determine the attenuation together. I do not see what you are saying.

If I have said the capacitor value does not matter when the control is on zero, that is a typo. I have said that on 0, the capacitor lowers the resonant frequency of the system. The capacitor value certainly matters; it determines how low the resonance goes, and so the frequency response.

[Mike Sulzer]

SK's plots at least prove that cap TYPE does change the audio signal....

SK discussed a couple of things his plots show. I think you are over-interpreting the plots.

I'm glad you're going to give this a try, you could also use a frequency analyzer to plot results, you can get free software for a PC that does this stuff, it doesn't have to be perfectly accurate, just repeatable, whatever method you use.

I already presented measurements, back a few pages, using the device I designed as part of the LC meter thread. The results show no difference between .022, .047, and a short across the cap, with 500K in series with accuracy to better than 1%. Calculations of the size of the effect on the impedance show it is much smaller than 1%. Hence my doubts on the validity of your sound clips, which show a large effect.

[Steve A.]

Yes, the series resistance is large, and guitar tone controls use the the pot as a variable series resistor. As a three terminal pot, the series and shunt resistance determine the attenuation together. I do not see what you are saying.

With a 3 terminal pot, try splitting up the series resistance and the shunt resistance, and see which of the two attenuates the signal more. Or it might be simpler to disconnect the ground lead from the volume pot on a guitar. Series resistance between 250k and 500k does not attenuate the guitar signal that much, and has a bigger effect on the implied and actual RC networks (which surprisingly enough include components both wired in series and in parallel). That principle is very important in the design and fine-tuning of guitar amps, but applies to guitar level signals as well.

Steve Ahola

[soundmasterg]

Mike,

I agree a double blind test is best, but in many cases it just isn't practical or possible to set one up. The people doing the test in this case would only need to be able to say either yes they hear a difference or no they don't. Identifying which cap was which to them wouldn't really matter. I've experimented with cap changes in amps with clip leads and while it is subtle there is a difference between cap dialectrics, and certainly between values. I happen think it is more obvious in an amp than in a guitar, but I can still hear a difference swapping caps on a guitar when the tone pot is still on 10. I don't discount that there are a lot of zeros there, but I can still hear a change. You'll probably refer back to the need for a double blind test, and thats fine, but I, and others can hear a difference, so the fact that you apparently can't or won't doesn't mean it doesn't exist.

Greg

[Steve A.]

I agree a double blind test is best, but in many cases it just isn't practical or possible to set one up...

Greg:

Agreed! I will be building the cap switch box so that I can test these premium caps throughout the entire range of 0 to 10, just to see if there are some that I prefer over the others. And hopefully to clear out some of the BS from the people selling these caps at outrageous prices...

The fact that a given cap produces good results doesn't necessarily prove that all other caps don't: I want to be able to do instantaneous A/B tests on all of these caps. I guess I really don't have to build the switch box right away but just solder in some tiny alligator clips in my PRS SE Singlecut II with a single tone control...

For many years now I've been happy replacing the cheap stock caps with decent 630v polyester caps from Mouser, et al- I think that they do a really great job! But maybe some of these premium caps do a better job- I dunno...

I shall soon find out!

Steve Ahola

[Mike Sulzer]

Mike,

You'll probably refer back to the need for a double blind test, and thats fine, but I, and others can hear a difference, so the fact that you apparently can't or won't doesn't mean it doesn't exist.

Greg

The fact that you think you hear a difference does not mean that you do. It has to be proven, either way.

"can't or won't": personal comment?

[Possum]

...

Well like I said my pickups are not factory junk or factory parts. These pickups are way more sensitive than anything you've probably played unless you've played a set of real PAFs, as thats basically what these are. As I mentioned just changing magnets shows a large effect in this, alnicos of the same supposed mix from different manufacturers show very dramatic differences in this pickup set. The cap change does show a marked change but nothing else was changed, doesn't matter what amp I play through the change is real. SK did a test that altered the guitar's circuit, so not surprised there. A test for this should be done out of the guitar's jack, he shorted the cap out which is something no one does when playing guitar, so I suspect something went wrong there. Anyway you're still the only one here who thinks nothing is happening, why is that?

[Mike Sulzer]

Well like I said my pickups are not factory junk or factory parts. These pickups are way more sensitive than anything you've probably played unless you've played a set of real PAFs, as thats basically what these are. As I mentioned just changing magnets shows a large effect in this, alnicos of the same supposed mix from different manufacturers show very dramatic differences in this pickup set. The cap change does show a marked change but nothing else was changed, doesn't matter what amp I play through the change is real. SK did a test that altered the guitar's circuit, so not surprised there. A test for this should be done out of the guitar's jack, he shorted the cap out which is something no one does when playing guitar, so I suspect something went wrong there. Anyway you're still the only one here who thinks nothing is happening, why is that?

So are your sensitive pickups necessary in order to hear a difference in cap value with a large resistor in series? If so, then why do you say that everyone except me hears it? Everyone is not using your pickups.

A few posts ago you were using SK's tests as support. Now there is something wrong with his tests.

Perhaps it is more clear now why it is necessary to find a way to remove all biases if you want test results that mean something.

[Possum]

...

Understand that I post during my working hours, so sometimes I read things too quick, I understood SK's charts to show measurable differences between values, maybe I was wrong. I didn't read the details of how he did the test. If he only got a 1% change, well thats surely not what I'm getting but he's not using my pickups and he's not using my guitar or the caps I'm using either, which was an extreme change of value and from a cheap chinese ceramic cap to a high end cap. I have no idea what his guitar is wired with. These days, if you've ever rewired any recent guitars they are loaded with crap wire and use computer quick connectors, garbage mini-pots and cheap switches. A cap change might not show much with all that stuff in there. My guitar is wired with Gibson style braided wire throughout the same as they used to be, good full size pots and these caps and good switches and jack, stuff that is way beyond the junk that came in this guitar. And believe me changing out all that stuff makes a huge difference in the ability of the pickups capabilities to get out the jack. So I don't know what guitar you are using whats in your guitar, you may not get anywhere near the results I am. I have about 16 guitars and learned the hard way that stock wiring harnesses in guitars under $1,000 were clouding what my pickups were doing.

Someone did mention that factory pickups don't show as much effect and I totally understand that because they aren't doing what was done in PAFs. Factory pickups use cheap metals that aren't optimized for magnetic uses, they are kinda dumbed down products designed to make a buck and sound good in a bedroom really. So, OK, you question my results, basically I don't need to do anymore work on this because it did what I wanted it to do, most of the other guys here are active in rewiring their guitars, changing out pickups, trying various pots and caps, way beyond what the average guitarist does. So they are saying here that what I am seeing in my guitar is real so that carries alot of weight with me because they are hands on types as I am and have to be in my business. I understand this is probably something of no consequence to you anway, alot of average players could care less whats in their guitars; I deal with high end players though who very much into fine tuning their tone so this stuff is very important in my business and am often consulted so have to be educated and experienced in as much of this topic as possible. If this is of no interest and you don't think it has any merit well thats your opinion, then leave it alone. I know its a real thing as most others do too and I have to make sure that whoever is putting my pickups in their guitar is going to get the maximum capability out of them so I need to know how to tell them what to do to get the best tone from my products. I have had several instances in the past where players bought my pickups and said they sounded muffled, dark, no zing etc. and after exhaustive email conversations it has always come down to stock crappy wiring harnesses in offshore guitars. Once they've replaced the junk the pickups do what they are supposed to do. Anyway, I'm bailing on this thread, just because you're not getting the same results I am doesn't mean your experience is the final word on cap value swapping, and you don't sound like you're much interested in what it can give you anyway........later......

[SteveJ]

Possum,

I wish you wouldn't completely bail on the thread. I am very interested in your findings. I think the focus needs to be returned to the original topic. We all know the science and theory but some have had different experiences. I don't think we need to cover what it should do any longer. I have done a lot of testing and have found what I like. It works for me but may not work for others. If people here have similar results then to me that stands for something. I think it's a great topic.

[GlennW]

I've done a lot of testing (by ear) with caps, on basses and guitars.

On basses I prefer the tone with a cap and no pots; I use cap switches for tone variation, no volume knob (should be one or two on the amp somewhere). There is a difference between different caps of the same value; OD polyester film, OD polypropelyne film, and Mallory 150s. It's a subtle difference, but it's there. I generally prefer the OD polyester, but not always, it depends on the pickup.

I tried the cap switch deal w/o pots on a guitar...sounded bad. I try a bunch of different caps and usually one or two stand out as sounding better, and that's what I use with that pickup in that guitar.

They do make a significant difference, and I think anyone who doesn't think so just hasn't tried it for themselves.

[David Schwab]

Glenn, are you the same GlennW who's currently talking about Guild bass humbuckers and Gibson mudbuckers over at TalkBass? I'd imagine you are, but it just occurred to me.

[MattT]

Mike,
When you say you cannot hear a difference...I believe you...you cannot hear a difference.

I say I can hear a difference (and not because I have dog ears...my hearing sucks).

[Steve A.]

Many thanks to Possum!

I really appreciate Possum starting this thread, and for posting his observations, his insight and his conclusions. Tone caps are something I usually just take for granted although my guitarist friends are often encouraging me to check out one premium cap or another.

Much of it sounds like hype to me- like spending hundreds of dollars for a Bumblebee cap or the cap from a 1957 strat: what is so special about them to justify the prices??? If you browse through an exclusive audiophile catalog you will find them selling "voodoo science" for hundreds or thousands of dollars per item. I can't fathom spending close to a thousand dollars on a pair of audio cables- only when you are spending that kind of money they are called "interconnects". Damn- that is just an audio cable that you bought for $800, sir!

Capacitors have many properties which contribute to their sound and response so you'd think that someone could find or manufacture a cap that could give you 99% of the performance of a vintage Bumblebee cap at 1% of the cost... The search for Holy Grail goes on!

Steve Ahola