Listening tests of high end capacitors...

[David Schwab]

That said... I do often use the 7XX series orange drops for builds for two reasons. The 7XX caps are film/foil non metalized and that is keeping with most vintage cap construction. I'm more concearned about tone than mojo, but when mojo is available buyers don't seem to mind so niether do I.

OK, so what tone or mojo are you expecting from a tone control cap? Why would vintage construction of the cap have anything to do with the tone of the guitar? It wont. When the control is on 10 it's not doing much of anything. Try a Fender TBX and see yourself. When you turn it down you remove highs. Neither has to do with tone or mojo. Does turing the treble knob down on the amp increase mojo?

Now, if you want to hear a difference, change the cap value. I like putting things like 0.01µF caps on guitars with humbuckers. It removes just the top end and gives a cocked wah tone. Better yet, use a push-pull or other switch and use multiple caps. Or go all out with a rotary and use a bunch of different caps. One is bound to have some mojo associated with it (probably the one that tunes to the pickup's own resonant peak).

but when mojo is available buyers don't seem to mind so niether do I.

But any cap on a tone control doesn't give you any "tone." Just takes away highs. There is no mojo (or spoon). Educate your customers.

[Rick Turner]

One issue that only a very few here pay any attention to whatsoever is the cost of needlessly expensive parts...for retail customer of a truly manufactured instrument.

I have to figure that any part that I pay $10.00 for has to be marked up by not only me, but also by the retailer; hence a $10.00 OEM cost is equivalent to a $30.00 retail cost to the customer, not factoring in all the bullshit of retail discounting. My costs are essentially marked up by a factor of 300% by the time the price tag is on at a store. This is the real world, folks, not the "work out of your spare bedroom or garage" world. I have no problem spending good money for good parts where the quality is evident, not smoke and mirrors, and where using cheaper (monetarily) parts makes for a cheaper (qualitative) instrument. I will not spend money on expensive parts where the expense is not justified by anything other than mythology or hearsay.

So, yes, I want to know if these $7.00 capacitors sound "better" in a passive treble shut circuit than ones that cost less than 5% of that. So far the theoreticians here who know electronics seem to be indicating that the only explanation for any possibility is distortion somehow bouncing back up from the cap into the signal path and then on to the amp. If the cap distorts, then at least most of the distortion will just be sent to ground, right?

And the folks here who have reported what I consider to be valid tests don't hear a difference. I'll still do my own tests.

Frankly, I find the idea of knowingly selling bullshit as mojo to be offensive, though heaven knows it's a common practice.

[Rick Turner]

It doesn't take a hammer!

We've measured 100 volt peaks from even piezo polymer pickups with a simple ball bearing drop from about 12". Not a big bearing, either... Under load and in a bridge it isn't that bad, and that peak is only on a half cycle, but it's there. It's one of the reasons why piezos "quack"...that quack is very quick clipping with the buffer trying valiantly to recover. We've found that going to 18 volt on-board electronics really helps; our D-TAR acoustic guitar pickups have become known for high headroom and low quack factor.

[Chuck H]

I think your misconstruing my use of the term mojo. And you sure seem to have your panties bunched up about it too. Funny as that is... Sigh...

Mojo is just the idea that certain types of construction or materials are somehow imbued with good tonal karma. Whether it's true or not isn't the point. It's not my job to tell my customers that the Easter Bunny doesn't exist either. And if your trying to assert that absence of something doesn't add to tone I would simply argue that there are a great many players that use the "tone" control on their guitar to get the "tone" they want. It's another etherial term that can only serve to cause antimosity when someone chooses to be semantic. The above statement in fact states that different construction probably WON'T make any difference in a guitar tone control circuits function. Who pissed in your Cheerios this morning?

Chuck

[Rick Turner]

Chuck, my remarks re. "mojo" were not directed at you, but rather the "School of Mojo"...luthiers and guitar tech types who sell utter fantasy and call it mojo. It is you who are getting the Philadelphia smile, not I.

If you choose to sell your customers the Emperor's New Clothes, as it were, well, caveat emptor and there's one born every minute. I choose not to do so, and my customers know it. If they choose to re-wire every guitar I make with mojoiffic parts, fine, but I'm not going to put expensive parts in my instruments unless I'm convinced that my customers are getting good and real value from it.

Proclaiming that one is selling mojo because you don't know what you're actually selling and you choose to imbue your products with some sort of magic (since you can't explain the electronics or physics) is for wankers. If other wankers want to buy the stuff because of marketing phraseology, that's their right. And I'm talking generally here, not specifically to any one member of this forum.

I have to say, I see an awful lot of attempts to sell mojo in the electric guitar world...more than in the acoustic guitar world. I think it's because we deal not only with wood, but also hardware (claims of magic qualities of metals, for instance...which may or may not be substantiated), and most mysterious of all for the lay public, with electricity and electronics which is still major "magic" to most people. I think that we, as electric luthiers, have a heavier burden to tell the truth than acoustic luthiers, and it's really easy to go mumbo-jumbo, get an Internet buzz going with a small team of fan-boys, and basically fool at least some of the people some of the time. I'm in it for the long haul...and have been for a very long time. I've not survived telling bullshit stories about how my stuff works; no side show snake oil here. It's a path that works.

Funny...Ha, ha...

[Chuck H]

+++ to all points made. But I think there's been a misunderstanding. You are probably viewing in "linear" mode (as do I) because in that mode my last post appears right after yours. If you view in threaded mode you will see that I was responding to David Schwab. See, He and I are just two knowledgable guys that don't always agree either in subject or approach. But for some reason he likes to try and twist my titties over it. Not sure why, maybe his wife treats him badly.

And FWIW I certainly do not, and would not market mojo to my customers. But I build custom to order so it's fairly common for a customer to want some specific "magic" part. I also always try to sell him/her a better part if one exists. If one doesn't then no one gets hurt and the customer thinks their amp is that much more special. Where's the harm? I can talk about mojo toungue in cheek with you guys but honestly, I wouldn't unnecessarily tell a customer, who really couldn't care less about the actual technical operation of their amplifier, that they are wrong when the part they want me to use is a good one anyway.

Please go back and re read the sequence of events as they actually happened and try to forget that I offended you. Because I didn't.

Chuck

[JGundry]

The Mojo lover seems to be the vintage purist. If they could afford a a vintage guitar that would be the ideal for them. If they can't afford one getting as close to vintage with newer gear is the ideal. Of course tonally they have to get what they are after.

The Mojo scoffer very often sees vintage as an arbitrary gold stamp for any old collectible guitar . The Mojo scoffer views the vintage as something to be improved upon based upon a mechanical construct and sees anything else as lack of progress. Of course tonally they have to get what they are after.

Just as a quick example. The mojo lover might play vintage electric into a Deluxe Reverb with nothing else and be amazed by the complexity of tone. The mojo scoffer would play his favorite active pickup guitar through a Line 6 going into a solid state amp and be amazed by the complexity of sound. Both are valid for the individual.

All that is needed for a scientific evaluation is a quantifiable set of parameters. The engineer often thinks if it is not quantifiable numerically it is not happening. The problem with this line of thinking is it tends towards the linear with all decisions. But music and musical instruments are not purely quantifiable in linear terms. Ears that are not addled by high frequency loss are the best judge IMO.

But in the end it all comes down to what the maker and the musician like and when they both meet you get happy customers and IMO this is what Mojo really is.

[Rick Turner]

Yeah, and I've actually had people tell me that hum was integral to the sound of vintage single coil pickup equipped guitars...

That without stopping to think how many fewer sources for hum were in the electronosphere in 1954 or '56, for instance. There was simply less hum in the air in the 1950s and probably by a factor of at least 500%! So the hum you get when using a '58 Strat is probably five times what you would have gotten, even at the same gain settings (which basically didn't exist and so it's a moot point) as you might use today. So what was acceptable in terms of noise pickup in vintage days is quite hard to deal with today, and saying that the guitars hum just like they did in '58 is simply wrong. In the same guitar, it's much worse now. And that's before we talk about sitting at a music recording work station surrounded by computers, digital outboard gear, and wall warts everywhere.

I, for one, do think there are a number of factors we've not yet figured out how to quantify, yet we hear them. I also think...no, I know...that there are factors that people think they hear and yet do not. A great example would be high end power cables to connect your amplifier to 110 mains power. Come on now...unless you replace all the wire inside the walls of your house and on back to the transformer on your street, six feet of mojo cable carrying 110 AC between a normal wall outlet and your amp is not going to make a difference unless your previous cable was woefully undersized. There certainly are things you can do to clean up your AC, but a $300.00 power cord isn't going to do it. Yet I know people who swear it makes a huge difference. I don't know...I don't do those drugs...

And I think the example of the Deluxe Reverb vs. a Line 6 is kind of a straw man. They are very different from one another, and even more different from the current discussion where we are talking about a component which takes away treble, and unless it somehow injects some sort of distortion or voltage spike back "up-stream" into the real signal path is not a component that is heard. There are very audible differences in analog and most current digital signal processors. The differences are becoming smaller as processing speed increases and bit rates grow, but still there are many ways...explainable ways...in which a Deluxe and a Line6 simulation are audibly different. That's not to say the Line 6 isn't useful...

I still think that there are a number of people here who simply do not understand the major difference between a coupling capacitor passing signal from one stage of electronics to another and the use of a cap as a passive treble shunt to ground. Hence the desire to hang onto "the sound of a cap".

[Mike Sulzer]

I still think that there are a number of people here who simply do not understand the major difference between a coupling capacitor passing signal from one stage of electronics to another and the use of a cap as a passive treble shunt to ground. Hence the desire to hang onto "the sound of a cap".

That's a good point. Let's look at how that works. A coupling capacitor has a low impedance, relative to the load that follows at the lowest frequency of interest. At higher frequencies the impedance is very small compared to the load. Thus the signal voltage across a coupling capacitor is very small. It has a significant dc voltage across it, of course; that is what it does: block dc and have enough capacitance so that the charge that has to be added or removed during an ac cycle is small.

Since the ac voltage across the coupling cap is low, the harmonics generated are relatively low and thus absolutely very low.

A capacitor in a tone circuit operates in a very different way. It is used to select some frequencies, and the frequencies that are cut appear as significant voltages across the cap. For example, a guitar amp tone stack is very sensitive to the quality of the capacitors. Not only can the signal voltages be quite high, but the response of the circuit with the controls running in the middle position is conducive to generating harmonics. This is because the response is far from flat, decreasing from low frequencies to the mid, and then increasing from the mid to the highs. Thus there is substantial voltage drop across one capacitor or another at nearly all frequencies.

The guitar tone circuit is much easier on the capacitor. Not only is the voltage quite small, but with most settings of the pot, only a small fraction of this small voltage appears across it, and the pot attenuates the harmonics going back into the circuit. It is true that when the pot is set to zero, all of the voltage appears across it. But at other settings, even when treble is being cut, the capacitor has little to do with it. It is really the resistor that is doing the cutting by loading the pickup. (The impedance of the capacitor is small compared to the resistance at most frequencies for most settings of the pot.)

So the guitar tone circuit is not a good candidate for sensitivity to capacitor distortion. But it is still more sensitive than a coupling capacitor. The concept of "in the signal path" is not valid for determining the sensitivity. It is necessary to analyze the circuit.

[Chuck H]

Yup. There are different cap constructions, and some behave differently than others when subjected to high voltage, heat, high current, etc... But at the temps and voltages found in a guitars tone circuit there is AFAIK absolutely no difference in behavior from one cap to the next. The exceptions being NP aluminums and notoriously poor cheap ceramic discs.

However, just to be clear (and play devils advocate, a task I find personally helpful in diagnosis of anything) if there was enough stress on the caps in a guitar tone circuit you absolutely would hear a difference. Why in the world would the difference in how a frequency is subtracted be any less audible than how it is passed??? The net result will still have anomolies in the frequency response of the circuit. So there. I said it. The fact that a cap is being used as a shunt or subtractive circuit does not take away from any audible difference in behavior under stresses. It's more about how these stresses simply don't happen in a guitar circuit. Believe me, if you ever designed an amp with an r/c shunt filter across the OT primary leads (conjunctive filter as they're commonly called) you would know that there is a difference in audible cap behavior under stress even when that cap is used as a shunt. These conditions simply don't exist in a guitar so all caps are created equal.

Chuck

[David Schwab]

Frankly, I find the idea of knowingly selling bullshit as mojo to be offensive, though heaven knows it's a common practice.

Greed is rampant as of late.

And I've got to wonder... does some guy wire $50 caps in his Les Paul and then sit back and convince himself that it sounds so much better? Do they really believe it, or they just want to believe it because they spend a lot of money?

[salvarsan]

It doesn't take a hammer!

We've measured 100 volt peaks from even piezo polymer pickups with a simple ball bearing drop from about 12". Not a big bearing, either... Under load and in a bridge it isn't that bad, and that peak is only on a half cycle, but it's there.

In short, you needn't worry about a voltage spike causing harmonic distortion in coupling caps since the piezo film pickup is already operating in distortion mode.

Any chance you can hang a bandwidth filter/spike snubber on the pickup?
An MOV or a pair of zener diodes would do.

[David Schwab]

The Mojo scoffer very often sees vintage as an arbitrary gold stamp for any old collectible guitar . The Mojo scoffer views the vintage as something to be improved upon based upon a mechanical construct and sees anything else as lack of progress. Of course tonally they have to get what they are after.

Nope. The mojo scoffer says that putting an old cap in a new guitar wont make it sound like the old guitar.

I have a friend with a '64 Strat he had since he was a kid. It's a lovely sounding guitar. He leaves that home of course, and plays a new Strat with Lace Sensors and a Dimarzio pickup at the bridge. It's a nice sounding guitar, but sounds much brighter and tighter. Swapping the tone caps would not make the new guitar sound like the old guitar. I'm not even sure swapping the pickups would do it.

So you have to draw the line between real character that comes with age, and some false pretense based on quasi old technology.

I have vintage guitars, like a '59 Jazzmaster and a '72 Mustang. I love the Mustang, but it sounds better with Lawrence L-250s in it. It snarls and growls. With the stock pickups it plinked. More modern pickups gives it more mojo. It would sound bland with EMGs.

[David Schwab]

Any chance you can hang a bandwidth filter/spike snubber on the pickup?
An MOV or a pair of zener diodes would do.

How about a neon bulb? Light show guitar.

[salvarsan]

The Aesthetics of Mojo

I understand and sympathize with David's aggravation at potential clients'
attempts to constrain him to something so medieval as mojo when he knows better.

At it's heart, belief in Mojo is a belief in magic.
It is a superstition.

Apologists can soft-pedal it as a rhetorical lapse where sub-articulate people
essay to express something ineffable, but I'm going make a risky assertion
that most 'mojo' believers aren't that intellectually industrious, choosing instead
to use the word as a tool for limiting choice, theirs and yours, to a vaguely defined
and somewhat deluded ideation system.

Much as you don't need God to understand morality and behave morally,
you don't need mojo to determine whether gear will sound good.

Aesthetic complaints aside, there does come a time when it is best to
shut your piehole and take the mojo-believer's money, cash, preferably.