heres an odd one

[daz]

Huh? What did i say to bing that on?! And as for being tone deaf, i assure you that i hear quite well, too much so actually.

Unfortunately, there are many perimeters of sound quality, that we have no method of measuring.
There is no meter, that equals the quality of the human ear.
We have many speakers and amplifiers, that are highly regarded as sounding "the best."
YET we have no real conclusive measurement that explains "WHY" we think it sounds the best.

You can measure all day long, with your large and expensive meter, that goes: "boing."
But none of your meters equals the quality of the human ear.
And for those tone-deaf, non musical techs who can't hear the differences, you are utterly clueless that the REST of us CAN hear a difference.
Can I tune a piano by ear? Yes
Can YOU tune a piano by ear? No, of course not, because you can't hear the differences between one note and the next!

So stop your pummeling, of those who can hear the difference. I can see that you are tone deaf. But that does not grant you the license.

[trobbins]

Nickb, was that a simulation plot? What did you measure?

[Enzo]

Daz, others said it already, your 0.68uf caps made the difference. But rather than looking for esoteric aspects of them like brand or length of lead wires or color of label, just measure the old ones, and measure the new ones and see how close the capacitance values are or are not. If one of your caps measures 0.5 and it replaces one that measured 0.8, I am going to bet on that difference being the reason rather than anything else.

[daz]

Daz, others said it already, your 0.68uf caps made the difference. But rather than looking for esoteric aspects of them like brand or length of lead wires or color of label, just measure the old ones, and measure the new ones and see how close the capacitance values are or are not. If one of your caps measures 0.5 and it replaces one that measured 0.8, I am going to bet on that difference being the reason rather than anything else.

I already did Enzo, but i was only able to check one of the "bad sounding" ones because i can't find the other 2. I must have tossed them. But i also had one other unused one i also checked. In any case they all measured close, from something like .72uf to .67uf. Nothing like it would take to hear the difference i heard.
On a side note, i tried those film caps an hour ago that i mention above and they sound horrid ! This circuit is a lot different than it was when i last tried them and like i said i think it's much more sensitive to cathode cap values/types. So far those older electros sound bets, tho i did notice only one is 100v. The other 2 are 50v. But they are all the same size and brand while those ones i canned were larger and a different brand.

[R.G.]

On a side note, i tried those film caps an hour ago that i mention above and they sound horrid ! This circuit is a lot different than it was when i last tried them and like i said i think it's much more sensitive to cathode cap values/types. So far those older electros sound bets, tho i did notice only one is 100v. The other 2 are 50v. But they are all the same size and brand while those ones i canned were larger and a different brand.

It's worth noting that to a component engineer, real-world parts are only an approximation to the perfect ones in theory. In theory, capacitors are pure capacitance, nothing else.

In practice, the component engineer models real world parts with combinations of parts. A "perfect" ideal capacitors can be dirtied up to approximate a real world capacitor by adding in some resistance in series (ESR) and in parallel (leakage), as well as series and parallel inductances. This can be carried out to any degree of modelling you want to take the time to do.

The important lesson to take away from this is that electrons do what they do, no matter what we think they ought to do. If one capacitor sounds different from another capacitor, it's either all in our minds, which lets set aside for the moment, or because the capacitance, ESR, leakage, ESL, etc. are different. In general, film capacitors have lower ESR, ESL, less leakage, etc. than electros, and are closer to ideal caps than electros. So we can dirty them up the same way an ideal cap can be dirtied up to match a more-imperfect electro. The advantage is that film caps do not drift and age like electros, so once you find the proper amount of dirt to make a film cap sound like an electro, it stays that way.

So if you can find your good-sounding electro and measure the appropriate stuff, you can approximate it very closely with some combination of film caps, resistors, etc. And once you're done, it won't drift away with time.

[Chuck H]

Sorry if this has been covered, I only browsed the thread. But IMHE electro's, especially those that perform poorly, are much more likely to be off their specified value. It could be that the favored caps sound best partly because they are a different value than the others. The value doesn't need to change much to hear a difference in the first triode bypass circuit. All the audible range is between .01uf and about 4.7uf. With only a few standard values that are ever used (.68uf, 1uf, 2.2uf, 3.3uf and 22uf). If, for example, the film caps are actually .61uf and the favored electro's are .76uf, that would certainly be an audible difference.

[trem]

I believe that for every audible difference between two sounds, there is a measurable difference. If you recorded the two sounds using our present-day audio technology, the waveforms would be different in a way that some sort of mathematical analysis could uncover.

In many cases, the difference isn't obvious using our usual test instruments (oscilloscope and spectrum analyser) and it's simply not worth the time to figure out an analysis that would uncover it. Nevertheless I believe that it is there.

I then turn this argument backwards: If some proposed change to a circuit wouldn't change the electrical characteristics of it, then it must make no difference to the electrical output, and therefore it can't make an audible difference to the sound of an audio circuit.

It follows that if one .68uF capacitor sounds different to another, there must be an electrical difference between them. Most likely one of them was not .68uF.

.

That has always been MY understanding.
Yet I hear/read guys swear that a cap with a Polyester dielectric sounds different than a cap that uses Polypropylene. I assumed it was due to their Actual Capacitance.
ALL else being equal, can one insulator respond differently at a given frequency than another type of insulator (in a capacitor) and cause what so many guys say are a bright, sterile, or even a Marshall, or Fender sounding cap.?
Thank You

[R.G.]

Yet I hear/read guys swear that a cap with a Polyester dielectric sounds different than a cap that uses Polypropylene.

I have hear/read people swear all kinds of things. Some of them are True Believers, some want to sell you something.

I assumed it was due to their Actual Capacitance.

The true actual capacitance is the biggie, the elephant in the room that high end capacitor salesmen don't particularly like to talk about.

Beyond that, there are no perfect capacitors. They all have some resistance to the leads, some inductance in the leads; they all have resistance to charge moving from where the leads touch the plates out to the ends of the plates, and inductance in the plates and how the plates are formed, often wound up in a spiral. They all have leakage through the insulator. There are other imperfections like dielectric absorption, odd electrochemical effects of everything in them.

If you can measure things finely enough, every physical object is different from every other, right down to where quantum effects mean you can't measure more finely.

However - the human ear is not that perfect a measurement device. There's a middle ground, where Steve's electrical differences can be measured, and where devices which are close enough (to some standard) will sound the same. You just have to find where that is. For instance, just reading the numbers printed on the capacitor is NOT going to get you close enough, especially when those numbers don't necessarily include the tolerances that the maker lets through. ]

It wasn't that long ago that electrolytics were commonly sold at a tolerance of -20% +80%! It's sure better to know that the cap in question is electrolytic, and therefore prey to aging, different and unspecified electrolyte goos in side, different spreading resistances, winding and lead-out patterns, voltage rating (and hence, thickness of the insulating oxide), age (and hence both capacitance changes and ESR changes as the electrolyte goo ages and forms/unforms/whatevers the insulating layer.

In film caps it matters whether the plates are actual metal foil, or just a whiff of aluminum vacuum sputtered onto the surface of a plastic film. The foils, thin as they are, have much lower resistance from one end of the plate to the other than a sputtered metalization thats a few atoms thick. And it matters whether the plastic/metal plates are stacked and hence less inductive, or wound up in a cylinder or oval.

This just goes on and on. Details matter. The devil is always in the details. There are people who have made a career out of figuring this stuff out - and others that make a living using the detritus of the details to sell more-naive people inexpensive parts at wildly inflated prices, or alternatively selling people mumbo-jumbo advice which sounds very mysterious and learned. Details do matter. The trick is figuring out whether what's being sold to you is real or not. As Steve says, if you can measure an electrical difference, that's a huge step toward being convinced that there really is a difference.

One has to know enough of the numbers to know what matters. The advice of a witch doctor - er, amplifier guru, sorry - is generally not a good guide. Knowing to match capacitance is a huge step. The next things to be measured are smaller steps, but can be important.

ALL else being equal, can one insulator respond differently at a given frequency than another type of insulator (in a capacitor)

Yes, they can. Insulators have different qualities. Often these are set forth as "dielectric constant", "dielectric absorption", "loss tangent", and other esoteric specifications.

The better question is can you hear the difference between audio through a capacitor of one insulating material, and another one **of the same internal construction** with only the difference of the insulator? If anything about the two capacitors to be tested is different except the insulating material, you have an invalid test.

Beyond that, it often takes frequencies and power levels outside audio use to be able to even reliably measure the esoterica.

and cause what so many guys say are a bright, sterile, or even a Marshall, or Fender sounding cap.?

I think that depends. A "bright" cap may just not have enough internal losses to dull highs, so it may well be a better capacitor, but the guy listening likes some treble wiped off. He may not -and probably doesn't - know that he's losing some treble with a dirtier cap, but only that he likes the dull ones better.

A **Marshall sounding** cap?? A **Fender sounding** cap?

Wow. Maybe in their head, and the heads of people they can convince.

[exclamationmark]

A spectral analyzer than can do bode plots would be helpful here - I actually DIY'd one with a $5 DDS module I got from ebay (basically a programmable signal generator, with a counterfeit AD9850), a microcontroller, and a couple of op-amps. I found some truly horrifying things with crusty old electrolytic that was at least 10 years old... Normally you would expect a high pass filter to have a linear slope when plotted on a logarithmic axis - However, if you set the load in the RC filter fairly low, it began to actually bulge/curve upwards, and in some cases could never reach the -3dB point, despite the frequency applied. This told me two things: 1). The capacitance was frequency dependent (it decreased with increasing frequency) and 2). The ESR was so high it couldn't even reach the -3db point!

I also devised a DIY capacitance meter (microcontroller enabled of course ), and I figure the stuff I learned making it would be of value to understanding capacitance. There are 3 ways of measuring a capacitance that I know of (there are probably still more out there!). Stick a suitable sized resistor on it, charge it up, and measure the time constant. Solve the time constant equation, and get your capacitance. Another method is by forming a low/high pass filter, injecting a known frequency and measuring the amplitude. You can then solve the voltage divider equation for the capacitance. Yet another method is forming an oscillating circuit - by determining the circuit parameters, you can then create an equation that you can solve for the capacitance (this is somewhat similar to the RC constant method). All these methods will (probably) give different results - but none of them are wrong. This is only one facet of a capacitor too! It doesn't even take into account DC bias or distortion.

That being said, I've seen some actual harmonic distortion measurements of capacitors using proper bridges. Most film caps have FFT spikes in the range of -100dB below the reference signal. Virtually inaudible. Dissipation factor/Dielectric absorbtion did indeed affect the results, but the total THD and spikes were so insurmountably small, I wouldn't even consider it when choosing different types of film capacitors. One thing I wonder about is the distortion measurements vs frequency. As far as I know, these tests were only done at a fixed frequency - Capacitor distortion doesn't exist in the ideal model of a capacitor, so it stands to reason that frequency may affect measurements as well (though I doubt it would make any huge amount of difference).

Human perception is a funny thing. It's no secret that I'm a huge cheapskate, and will absolutely not spend money on anything unless I have to (ebay and china are literally my best friends). That being said, I think this actually changes the way I perceive sounds. I've done numerous A/B re-amped, switched coupling capacitor tests and I can't tell a damned difference between them! I don't know if the differences are actually perceivable (what would determine them being perceivable?), or if I'm in denial .

[Steve Conner]

Daz, for the sake of scientific curiosity can you try putting some resistors in series with the horrid-sounding film caps and see if that improves the sound? I'd guess something like 10 or 22 ohms. I think they must have too low ESR, so you get too much treble boost.

I don't know about audible differences between the various plastic films. I do know that I built a low-distortion oscillator using random plastic film caps pilfered from the stock room at work, and got 0.002% distortion from it. That doesn't leave a lot of room for audible artifacts. I've had similar experiences using large MKS4 caps as DC blocks in hi-fi circuits: while I've seen internet audiophiles trashing the MKS4 dielectric (polyphenylene sulphide?) they seem to "just work".

I could believe that some random 50 year old capacitors might have aged in ways that gave them a very distinctive tone. Moisture, poor contact between lead wires and metallization, and so on. I would call these "broken".

[Enzo]

SOme guys swear that such and such a brand cap really improved their tone. But how many of those guys changed ONE cap and then reported on the difference? None of them. Not only that, how many of those guys installed their new fancy caps in place of old worn out caps in the first place? The real test is to use brand new cheap caps, and then substitute brands new fancy caps to hear any difference. And all the while matching vlaues of course. Replacing old worn caps with new ones can make any cap sound great.

[Steve Conner]

For an ideal capacitor, the three methods Mark mentioned should give the same answer.

Dielectric absorption is a linear phenomenon. It makes the capacitor's impedance change with frequency at a slower rate than the usual 6dB/octave, but it doesn't generate distortion. The usual model is a bunch of Rs and Cs of different values, shunted across the ideal capacitor. So, if a capacitor in a tone network had a lot of dielectric absorption, it might conceivably change the tone slightly.

Here is the best story I know about "capacitor sound". I might have told it before but I'm going to tell it again. A while ago I bought a couple of low-cost parametric EQ units. After using them for a while, I became aware of a kind of annoying bloated, fuzzy quality to the sound when the bass filter band was used. I hooked the unit up to my distortion analyzer. With all the EQ controls in the flat position, it met the 0.05% distortion spec in the manual, but when the bass control was turned away from flat, up to 1% distortion appeared. The residual was a nasty, lumpy waveform full of odd harmonics.

I opened the unit up to find that the maker had used tiny surface-mount ceramic caps in the filter networks. He could probably get away with this in the mid and treble bands, but the values needed for the bass filter would require one of the high-K dielectrics, whose capacitance changes drastically with voltage. Since the capacitors in the filter network see lots of signal voltage, the result would be harmonic distortion of the kind I heard and measured.

I got a Behringer digital EQ instead.

[Jazz P Bass]

Here is a nice little ditty about how caps 'really' work.
ELECTRICITY MISCONCEPTIONS: Capacitor

[trem]

You guys have really opened my eyes (and mind) to the fact that YES, different types of caps do/can sound different. But the reasons are more involved than what most guitar players realize. Certainly more involved than the advertising that Sozo has been so successful with. More involved than Orange caps are bright and sterile, and yellow caps are warm and "mid-oriented".
Maybe it is just the circles I travel in. But I so often hear guys discuss a coupling cap change as being so drastic (between two types) that it goes beyond their amps ability to counter the "change" with the knobs on the amp.
Anyway..... thanks for enlightening my blue-collar perspective on this crap.

[Steve Conner]

YES! You got it!

I've seen a lot of highly intelligent people change out components and wax lyrical about the results. The weird thing is, their descriptions are exactly what you would expect if they just took their knowledge of how the components were constructed, and let that guide their fantasies of what they thought they heard.

So for example, metal film resistors sound metallic, ceramic capacitors hard and brittle, oil-filled capacitors sound fluid and organic (and great for playing slide guitar... ba-bump... not my joke I hasten to add )

Whenever I read stuff like this, it is very tempting to dismiss it all as experimenter expectancy that wouldn't survive a blind test. The truth is a lot more complicated. The effect that a material has on electricity flowing through it doesn't necessarily have anything to do with what it looks like, feels like to the touch, smells like or sounds like when you hit a piece of it.

Except sometimes it does, as in the case of microphonic tubes that make the same noise through the speaker as they do when you hold them to your ear and shake them.

As far as I know, Sozo capacitors are good quality and not really that expensive compared to audiophile-grade stuff. And the logo looks a bit like Jimmy Page's symbol from Led Zeppelin 4.