Big 'Mojo Components Debunking' thread

Ok, you got your soldering iron and nothing is going to hold you back, but you have no clue where to start or what to build. There were others before you with the same questions... read them first.
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teller
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Post by teller »

Bummer, :cry:

I was pretty excited about this thread, I thought finally we had gotten some clarity on the whole "science proves what is real" thing...All I wanted was to understand the science that was being vehemently professed by analogguru and Super velcroboy, they did a great job!!...but, now I am not so sure, I thought Skreddy was off base with his assertions, but if it is just back and forth talk without the specifics of the science, then it was simply more banter, and that would suck!

I just wanted understand the capabilities of the equipment used to proves the science and be sure that we understand physics to the point that we are positive that the measuring devices can account for every variable in sound. My question are in this thread, they are easy to answer for any of the guys who used the equipment and proved Skreddy wrong.

I would not mind owning the same testing devices that analogguru and super velcroboy used to prove their comments, so a model number and some basic settings would be awesome too, so I can conduct my own tests and share results in the future too!

Don't leave me hanging guys, I am counting on ya!

:)

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Post by soulsonic »

You have not read any of my posts, have you? I answered your questions in a way which proves that both sides have valid points.
I think you are just trying to provoke people.

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Post by BJF »

Hi,

Good parts?

Well I wouldn't think there would be a standard answer other than what perhaps fits the criterias set for a circuit

If the circuit has high voltages carbon comp resistors can take higher voltages than metalfilm of same size.
The difference can be over 400V's.

Carbon Comp resistors have more noise than metalfilm due to impurity in the materials and the CC's can also pick up moisture and this shows up as random noise.

Metalfilm resistors have lower noise due to purer materials, but require larger sizes in high voltage circuits to withstand voltage.

Metalfilm resistors go into short circuit while CC's go into open circuit when overloaded beyond.

CC's have sturdier mechanic structure than MT's and can thus absorb vibrations to a greater extent, while this is a minor issue as resistors can be mounted in several ways.

MT's have tighter tolerances than than CC's and thus deviate less from stamped value.

There are also carbon film resistors and those have lower noise than CC's but higher than MT's and also go into open circuit when overloaded and have looser tolerances than MT's

Resistors become many components at high frequencies ( beyond human ear)
This is important in for instance radiotransmitters and recievers et.c
Generally inductances and capacitances and other 'ghost' components that show up in a resistor at VHF are of no significance at audio frequencies.

Now a circuit like an amplifier of sorts behaves one way in the audio range and in another at frequencies higher than human hearing allows. This can be of great importance in poweramplifiers that can self destruct
from oscillations if safety measures are not taken but that is a whole other subject.

Anyway back to resistors, if a 9V treblebooster is built on a pcb I'd see no reason not to use MT resistors
for reasons of minimizing noise as I'd view that as the most important aspect and there would be no mechanical issues or high voltages or risk for short circuit.

I might have another view if the resitors sits in a powersupply or highvoltage poweramp et.c

Capacitors:

the one thing often overlooked with capacitors is the actual value and ability to hold the value in audiofilters, and it may be the singular important thing in a circuit.

Some filter circuits like Biquad, Twin T Notch et.c et.c really rely on tight tolerances and in for instance the TTN
this sets both the Q and the depth.
1% types or better are generally prefered in filters

Ah, now a capacitor may sit between the collector and base of a transistor...............now there's also a ghost component known as Miller capacitance that is created within the transistor and is amplified by the gain of the transistor. The cm, is found in the datasheet of the transistor and is easily computed, and it sits then in parallell with the external capacitor and the combined value of those is then amplified..........

Now some capacitors can be microphonic- depends on the circuit

Generally capacitors don't generate noise -unless they are cheap elko's in which case noise can be generated.
In old guitarpedals one can use freezerspray to detect such a noisy cap and it is done by freezing one cap at a time and listening to the output for changes in noise-if there is a change when freezing one cap that cap is faulty.
Capacitors that are used frequently stay healthy and lifetime for an Elko can be at least 30 years if it is constantely used.
Check capacitor datasheet provided by most capacitor manufacturers for further information on lifetime expectancy as this depends on type and what voltage is applied.
However if you find an old tubeamp in a barn somewhere be vary that old elkos dry up- in some cases one can restore such caps, but that would likely only be an option if there is no mechanically suitable replacement.

Capacitors also have a set of ghost components and thus come into play and become important again at high frequencies above human hearing and wether it affects again depends on what happens in the circuit at such high frequencies

Uh, I think this must be all for this time as capacitors is a huge subject, but I'd say for guitarpedals I would not see any reason for using other than polyester or polypropylen capacitors that are small, mechanically stable and can take most cleaning substances, and there are these days fine low noise elkos, however the really small ones may have shorter lifetime depending on the circuit type, while in guitarpedals that would be........well not really something to worry about ;)
Of typical interest in a circuit would be mechanical stability also with capacitors

Ah, but one more thing so those old germaniums- the 'pop corn' trannies those do have a lot of inherent noise and also this pop corn noise that stems from impurities in the materials and usually very low gain.
There would as I see it only be two things of interest when looking at a transistor like for instance OC44 in a treblebooster for guitar and those would be the low ft and possibly distortionlevels.

Right, well then this with potentiometers...............now since musicians sometimes operate potentiometers with their feet it would be nice if the whole shaft wouldn't protrude the potentiometerbody during such circumstances.
Some pots have a flange others one can like MXR put a relief washer on.
The lifetime of potentiometers is defined in the specifications for the potentiometer and so is noise.
Some pots are sealed and that is a good feature in guitarpedals since little particles can enter the box via input and output jacks

A pot is a mechanical part and a mechanically sound one with good lifetime expectancy may cost a little.

Buying parts in just one or two or for just one pedal can be really expensive but parts in bulk gives reasonable prices.
The parts you'd pay for in a commercial guitarpedal would bethe mechanic structure and the mechanical parts.......

Have fun
BJ

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Post by Deric »

All of my testing in 9v powered circuits showed little (if any) difference in tone from component type. This was NOT true when values differ - say a 149.89k metal film resistor versus a 162k carbon comp. On some occasions I "thought" that carbon comp was noisier.

That being said, ALL of MY tests were VERY un-scientific. I have no data to back it up. I used my ears......

While I generally blow off the "mojo" tone hype, I certainly respect builders (like Skreddy) who insist there is a difference. I used to race cars and a common term we used was "bench racing". At the end of the day, "we don't race dyno's". My point being, regardless of what the "numbers" say, all that matters is the result.

In the pedal world, we don't play through test equipment. As much as I lean to the "if you can't measure it, it ain't real" side of the argument, in the end ALL THAT MATTERS is if it sounds good to YOU.

My question to Skreddy regarding "specific values" in a circuit was in no way meant to offend. Quite the contrary, I'm genuinely interested in his response.

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Post by BJF »

Deric wrote:
While I generally blow off the "mojo" tone hype, I certainly respect builders (like Skreddy) who insist there is a difference. I used to race cars and a common term we used was "bench racing". At the end of the day, "we don't race dyno's". My point being, regardless of what the "numbers" say, all that matters is the result.

In the pedal world, we don't play through test equipment. As much as I lean to the "if you can't measure it, it ain't real" side of the argument, in the end ALL THAT MATTERS is if it sounds good to YOU.

.
Hi,

I would agree.Also that many times it is not the component but how you use it.
As a musician I'd look for something and would not care how it is done, as long as it sounds good and holds up,while as a technician I'd disregard mojo when there is a scientific model.

Have fun
BJ

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Post by soulsonic »

That's the attitude I try to have.

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Post by teller »

soulsonic wrote:You have not read any of my posts, have you? I answered your questions in a way which proves that both sides have valid points.
I think you are just trying to provoke people.

Yes I read your post, but it did not address the questioned I asked, you post went out of it's way to not answer my simple and direct question. You made the mistake, that my post was time for philosophy. I appreciate your effort, but I was looking for facts, these facts were more than alluded to vehemently throughout this thread. I want to stick with the topic and the program.

I will break it down for you again so you can decide of you have the actual answer, or just want to post.

Simple questions:

What are the test/measuring devices used to test if a components difference can be heard by human ear?

Model # and some basic getting started settings if needed?

Do we understand physics perfectly to the point we are sure the measuring equipment is taking into account all possible variables? Yes or no! (please no flowers and analogies)

Do the measuring devices outperform the human ear at all possible variables?


how would this provoke somebody who had not lied about their assertions about tone, mojo in this thread? Provoke? I don't get your attitude.

I would think they would simply answer my simple questions without flowery analogies, philosophy or dodging...just model number, here's a getting started tip, yes, no, yes etc... easy for anyone who was being honest through this thread, and certainly no hefty effort.

If my direct, truthful and simple questions inflame, or have to be answered in electronics version of political rhetoric, then this thread was a waste of all of our time...and it outed a few people at the same time. That would be a damn shame.

Thanks for helping with component questions BJF! you are most appreciated here, if nobody retorts, i will guess they all agree
:)

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Post by MoreCowbell »

BJF wrote: As a musician I'd look for something and would not care how it is done, as long as it sounds good and holds up,while as a technician I'd disregard mojo when there is a scientific model.

Have fun
BJ

AGREED, 100%.

BTW...Thanks for "weighing in" with your component info above Bjorn.

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Post by soulsonic »

Teller, your questions are asinine. You're asking if it is possible to make Objective measurements of a Subjective experience.
The answer is NO.

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Post by MoreCowbell »

teller wrote:
Simple questions:

What are the test/measuring devices used to test if a components difference can be heard by human ear?

Model # and some basic getting started settings if needed?

Do we understand physics perfectly to the point we are sure the measuring equipment is taking into account all possible variables? Yes or no! (please no flowers and analogies)

Do the measuring devices outperform the human ear at all possible variables?

If they were "simple questions", then people would have answered already. The fact is that ...

question #1.... the wording makes it tough to understand what you are asking.

question #2.... model # ? settings ? for what ? I'm not following...does this have to do with an earlier post ?

question #3... of course not. We learn new things every day. Is it "just physics" ? Do we know "what" we should be testing for with regards to differences in components ?

question #4... How could measuring devices outperform the "ideal" human ear ? We can't measure everything that the ear hears, so outperforming it is a moot point...HOWEVER...you also must take into account that measuring devices can be made to be remarkably consistent, whereas the human ear, by nature, us remarkably inconsistent, and constantly changes / degrades throughout our lives. Every human "hears" differently, so with regards to "components"...it is entirely possible that one person can hear a component change differently than another. The problem is that one person may find that change "favorable, the other may not.

I hope this helps...I couldnt understand the wording on the first few questions...

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Post by MoreCowbell »

soulsonic wrote: You're asking if it is possible to make Objective measurements of a Subjective experience.
The answer is NO.
And "Yes".

And "Maybe".

It depends on the person.

:)

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Post by teller »

Here are the quotes that got me thinking there were measuring tools/devices that could hear differences better than the human ear:


"Problem is some people are satisfied with their ears only but can't seem to measure these differences in any objective way, and they refuse to try to do so. I have problems with these people."

"I am not talking about myths or subjective impressions, I am talking from a scientific viewpoint. As long as you cannot proof (me) on a scientific basis - reproducable and measurable - that the use of carbon comp resistors in a 9V fuzzcircuit has a (significant) influence on the sound result of a fuzz-circuit (the material and not the tolerance of it) the claim is unproven and bullshit."

"If there would be a smoother sound it would be measurable - at least with fourier-analysis. So proof it, or accept that I won´t waste my time in such a worthless mojo-discussion. What YOU believe that you can hear is not important in such a discussion even when another also BELIEVE that they could hear something - without a double-blinded-test."

"ojo is like a religion, which is based on faith.
Mojo is not science, which is based on empirical measurements and observations that are hypothesis-driven.

It's hard to let go of mojo, because that is like not believing in santa claus and the tooth fairy."

"I know this....
I will not engage in this worthless discussion again...
we already had a thread about this with experts... "

"there is no point missed. My point to you is, and i stress... if you are a true scientist or someone who is truly critical, you would rely on more than just your ears. You say why you should prove to me... okay let's say for example you want to pass these secrets down to your apprentices so that the "art" can be continued. Let's say your apprentices can't hear a god damn thing that you are hearing. What then? Do you say they have bad ears? This is why you SHOULD try to prove it, because it will be lost with you and you will be the only one to believe it. Well you and your fans, but most of them wouldn't know a resistor from a capacitor. "


In these quotes over and over again, analogguru and super velcroboy refer to measuring sound to see if it is "smoother" more "mojo" ect, and using science to prove that difference in sound if it really exists, are you saying there is actually no measuring devices on earth that can do what they are saying? To be able to prove something better or worse sounding definitively? I can't imagine that, I just want to get my hands on something that produces the results that the "experts" referenced to in this thread used. I am just saying there has to be something to base these claims on, and it need to hear all the ear can hear to be a proper counter response, which means understanding all that is possible for the ear to hear.

I mean, how can Skreddy prove his point, if nobody made the definitive machine to make that measurement with? see my point?

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Post by MoreCowbell »

teller wrote:
In these quotes over and over again, analogguru and super velcroboy refer to measuring sound to see if it is "smoother" more "mojo" ect, and using science to prove that difference in sound if it really exists, are you saying there is actually no measuring devices on earth that can do what they are saying?
No...what I'm saying is that perhaps we don't know WHAT to measure. Human ears hear differently from person to person, but certainly generalizations can be made.

With regards to "stompboxes", my feeling is this: "Science" can point you in the right direction, but ultimately our "ears" are what bring us to the destination.

Have a "non-musician engineer" design a fuzz pedal from scratch...chances are that it won't sound good, or will need a "musician" to tweak it.

My $.02 ...and you CAN'T tell me I'm wrong (or right, for that matter), because it is simply "my opinion".

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Post by modman »

https://www.muzique.com/editor.htm wrote:May 14, 2000 - 20 Commandments of FX Design

1. Analog rules.
2. Exotic opamps usually aren't any better than regular opamps for FX.
3. True bypass will not fix a crappy sounding effect.
4. Ge transistors do not guarantee a good sounding unit by themselves.
5. Oxygen-free hookup wire doesn't make a bypass switch sound any more transparent.
6. A Mil-Spec doesn't mean the part is any better than commercially available parts.
7. You cannot truly imitate tubes with transistors; not even jfets.
8. All 4558 opamps sound the same in Tube Screamers.
9. Starved-plate tube circuits don't really sound that great.
10. Double sided pc boards with plated-through holes aren't any better than single-sided boards.
11. High gain usually means high noise.
12. An effect that sounds great today, may not sound so hot tomorrow.
13. Gold and silver plated jacks are attractive but that's all.
14. Using plastic enclosures does not mean the device will pick up hum.
15. Clean boost does not come from an overdrive unit.
16. True Class A doesn't mean anything in FX circuits.
17. Jfets are just as static-resistant as bipolar transistors.
18. If there is a chance to put the transistors in wrong, you probably did.
19. Fresh 9v batteries all sound the same.
20. Just using a vintage pedal never made anyone a guitar legend.

©2000 by Jack Orman
Please, support freestompboxes.org on Patreon for just 1 pcb per year! Or donate directly through PayPal

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Post by seniorLoco »

12. An effect that sounds great today, may not sound so hot tomorrow.
[smilie=pope.gif]
"Curiosity may have killed the cat, but it saved the mice, who ate the cheese."

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Post by R.G. »

teller wrote:What are the test/measuring devices used to test if a components difference can be heard by human ear?
Double blind A/B/Y tests. Very, very effective.

It's been proven that the human ear can hear differences in the SAME component if it wants to badly enough.

The human ability to convince itself that it sees patterns in noise is well documented.
teller wrote:Do we understand physics perfectly to the point we are sure the measuring equipment is taking into account all possible variables? Yes or no! (please no flowers and analogies)
This is a classic diversion - comparing the problem at hand to the sensing of anything in the universe. I've used it myself when backed into a corner at a technical meeting. It works GREAT as long as the audience doesn't recognize it for what it is.

If the argument is that the human ear can hear things that can't be measured by any instrument, then that may be true - both if there is a difference and if there is not. See the answer above. And read up on Clever Hans.

And it's impossible to say that every possible thing has been measured/accounted for, just like it's impossible to prove a negative.
teller wrote:Do the measuring devices outperform the human ear at all possible variables?
Same question, different way of stating. What measurement devices do is
(1) Completely remove bias, as long as the user can't nobble the readings. Instruments, imperfect or not, have no interest in their readings.
(2) Produce NUMBERS, not "it starts with a taste of oak, and finishes with a hint of raspberries and parsnips." NUMBERS can be tested, repeated, reviewed for accuracy, statistically tested, and so on. A "Golden Ear" will ALWAYS tell you that your instrument is just not as good as his ear. Otherwise he'd have to admit he's not a Golden Ear, and people don't do that once they don the Golden Ear crown.
(3) Allow repeatability.
(4) Avoid fatigue, low blood sugar, marital disputes last night, hangovers, etc. in measurements.

Read some of the difficulties in psychological testing, then come back and tell me that human opinion is always more reliable than measuring instruments.

By the way, there are (a) well set up (b) repeatable and repeated tests that show that in certain circumstances, the human ability to hear distortion vanishes at distortions under maybe 1/2-1%.

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Post by super velcroboy »

good post RG. You try to take the most objective path.

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Post by analogguru »

here we go for pseudo-science:

http://www.dself.dsl.pipex.com/ampins/p ... bjectv.htm

analogguru
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Post by NickS »

"Cables are directional, and pass audio better in one direction than the other."
Jeez.

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Post by analogguru »

NickS wrote:
"Cables are directional, and pass audio better in one direction than the other."
Jeez.
Never heard about that ? The Mojo-explanation is very simple:

Cables consists of copper in pure ion-form. These ions act like a bunch of little diodes resulting that the signal goes in one direction better than in the other direction. One guy tried to proof this to me 20 years ago....

I couldn´t hear the difference.... instead I found out, that on his right box the mid-speaker was broken... This I COULD hear - he not.

analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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