carbon comp resistors

[Mark]

carbon comp is premium resistor if you know how to use it. it is non inductive.. and like that, best can be used where?

I thought there are other carbon film resistors which are non inductive.

https://www.hificollective.co.uk/sites/ ... _pdf_1.pdf

[Charlie Wilson]

Bottom line, if you don't hear the difference, don't worry about it. However, that does not mean there is no difference.
CW

[Mark]

Bottom line, if you don't hear the difference, don't worry about it. However, that does not mean there is no difference.
CW

I agree with what you say. However, if there is a difference, then that difference should be able to be demonstrated. The high frequency response of a guitar amp isn’t that high, so surely most people would hear the difference. I think there is an attitude that carbon comps are different but no one can demonstrate it or replicate it. That does make me somewhat cynical to these claims. I’m not anti carbon comp and I look forward to be proven wrong about tonal differences but I have looked for videos and recordings showing the differences and it’s not happened for a long time.

The link has a guy demonstrating the difference in Jupiter caps, so it’s possible to capture differences in components.

https://youtu.be/v0bOorfux-c

[martin manning]

Easy to hear the difference in frequency response there. I see that the labels on the two types of caps are oriented the same way in both amps. I wonder if the outer foil corresponds to the label? Jupiter data sheets don't seem to mention anything about that.

[romberg]

The link has a guy demonstrating the difference in Jupiter caps, so it’s possible to capture differences in components.

https://youtu.be/v0bOorfux-c

While the sound clips here do show one amp being noticeably brighter than the other, can this difference really be attributed to the caps? Are the amps really identical? For example, what if say one or more of the pots in a tone stack differed a bit from amp A and B. Something like that alone could account for what is being heard. There are too many variables that have not been fixed in order to isolate the change in "tone" being caused by just the caps.

A more carefully controlled test would be to use a recorded DI signal for the input. Then record the amp with cap brand A. Then very carefully (without touching anything else in the amp at all) replace the caps with brand B. Finally record the same DI signal again using the exact same amp and setup for test A. My guess is that this would produce results that would be more difficult to tell which caps were which.

I'm always skeptical of component behavior that seems to elude detection by any piece of test equipment other than a guitarist's ears .

[Mark]

A more carefully controlled test would be to use a recorded DI signal for the input. Then record the amp with cap brand A. Then very carefully (without touching anything else in the amp at all) replace the caps with brand B. Finally record the same DI signal again using the exact same amp and setup for test A. My guess is that this would produce results that would be more difficult to tell which caps were which.

Signal going into the amp was from a looper of some kind, so the input signal is the same. I’m not too worried about the tolerance of the resistors and the pots as that will be +|- 5% to 10%, though caps have loose tolerances. The tolerance of the transformers is an unknown, I have never heard of anyone discussing the tolerances of a transformer.

I don’t know the results would be the same with different caps, I also wonder if the difference is more noticeable in amps with more caps?

The point I originally was making was people have made recordings demonstrating the differences in components, but somehow carbon comp and carbon/metal film resistors miss out.

[romberg]

I’m not too worried about the tolerance of the resistors and the pots as that will be +|- 5% to 10%,

I'm sure most folks in this neck of the woods have measured pots. Have you ever measured a 25k pot (say for the mids on a tone stack) and found it to be 25k? They almost never are. They are all over the place. And that is just the end to end measurement. Now consider two "identical" pots at 50% of their rotation. The values you get will be even more off.

I'd bet that many "log" pots can vary enough in their curves that one pot on "5" is the same value as one pot on say "7". Most folks can hear the difference in frequency response between an amp with say the treble on 5 and it on 7. But if this is not taken into account then you will have two test amps, both with treble set on 5 but one being more brite just because it's treble pot has a different resistance on five than the other.

I'd bet that something like the Duncan tone stack calculator would show two noticeable (more than a couple db) difference between curves of the exact same tone stacks except stack A has a 28k mid pot and stack B has a 22k mid pot.

How come these cap frequency response differences never show up with a simple function generator -> RC filter -> scope type setup using typical guitar amp voltages and frequencies? Maybe such tests exist and I've just never seen them. A test like this seems so simple to do (compared to building two identical amps) and would more or less be the end of debates like this. Capacitor manufactures (and their marketing departments) could point out their test results as selling points. Yet this does not seem to be a thing...

Mike

P.S. Mark I'm not railing at you. Just at some of the common knowledge that seems to have little backing it up

[bepone]

I'm sure it is possible to demonstrate carbon comp vs metal film per example. With spectrum analyser easy. Also the effect is cumulative in several anode positions.

But why i need to spend half day to do that, and make video, for who? Some random guy on the net? So he can from sitting in his chair and finger in the nose digging gold, approve or not? I'm sure I have smarter things to do.

The guy who wants to know difference, instead waiting for the technical dissertains, test conclusions, analyze /what he doesnt believe at all/ etc from the other guys on the net, need to do the homework. Build actually something, spend 50-100hours invest 500-700 $$ in the amp, and start to change the components, one for the other. After, with playing on the guitar he can detect if there is or not, and then can come here for discussion, what he can hear, what is better for him and so on....

[pdf64]

Signal going into the amp was from a looper of some kind, so the input signal is the same…

Around the 2 minutes in, the video shows a guitar being played in both scenarios?
And no mention is made in the video description of a prerecorded loop being used as the signal input.

In that type of demo, ie someone noodling away on guitar, it’s tricky for me to hear such subtle differences. Subtle to me, at least.
Whereas any difference is readily apparent if white or pink noise is used.

… I'm sure I have smarter things to do.
....

Such as documenting a justification here why not to do it? FYI I have on good authority that certain members here are dreadful nose pickers

[jabguit]

This....

Bottom line, if you don't hear the difference, don't worry about it. However, that does not mean there is no difference.
CW

cheers,

[Mark]

But why i need to spend half day to do that, and make video, for who? Some random guy on the net? So he can from sitting in his chair and finger in the nose digging gold, approve or not? I'm sure I have smarter things to do.

I had better things to do than chasing down circuits and building prototypes when the forum was still a Yahoo site, but I did it for the greater good. The forum you see here today is a result of people giving. Perhaps this is your chance to give to the forum.

http://ampgarage.com/forum/files/Mark_R ... fo_cct.jpg

http://ampgarage.com/forum/files/Expres ... iation.jpg

http://ampgarage.com/forum/files/Expres ... rawing.jpg

http://ampgarage.com/forum/files/liverpool_layout.pdf

[bepone]

I had better things to do than chasing down circuits and building prototypes when the forum was still a Yahoo site, but I did it for the greater good. The forum you see here today is a result of people giving. Perhaps this is your chance to give to the forum.

http://ampgarage.com/forum/files/Mark_R ... fo_cct.jpg

http://ampgarage.com/forum/files/Expres ... iation.jpg

http://ampgarage.com/forum/files/Expres ... rawing.jpg

http://ampgarage.com/forum/files/liverpool_layout.pdf

ok respect.. the young generation all want today something without any effort , so my comment was cumulative for all what i'm seeing last 5-10 years everywhere..open youtube and thats it..all is there. practice is all what is count, here and in other hobbies/works,at least from my point of view and i'm seeing often philosophers.....

[Mark]

Around the 2 minutes in, the video shows a guitar being played in both scenarios?
And no mention is made in the video description of a prerecorded loop being used as the signal input.

In the comments you can see that I asked him that very question and he replies that he used a looper. The playing might be for content.

[pompeiisneaks]

I had better things to do than chasing down circuits and building prototypes when the forum was still a Yahoo site, but I did it for the greater good. The forum you see here today is a result of people giving. Perhaps this is your chance to give to the forum.

http://ampgarage.com/forum/files/Mark_R ... fo_cct.jpg

http://ampgarage.com/forum/files/Expres ... iation.jpg

http://ampgarage.com/forum/files/Expres ... rawing.jpg

http://ampgarage.com/forum/files/liverpool_layout.pdf

ok respect.. the young generation all want today something without any effort , so my comment was cumulative for all what i'm seeing last 5-10 years everywhere..open youtube and thats it..all is there. practice is all what is count, here and in other hobbies/works,at least from my point of view and i'm seeing often philosophers.....

I personally tire of hearing this refrain. I'll show you a quote that shows you the timeliness of the 'youth of today' complaint:

“The children now love luxury; they have bad manners, contempt for authority; they show disrespect for elders and love chatter in place of exercise. Children are now tyrants, not the servants of their households. They no longer rise when elders enter the room. They contradict their parents, chatter before company, gobble up dainties at the table, cross their legs, and tyrannize their teachers.”

Guess who said this?

Socrates.

He was born 470 BC.

So 'the young generation' has been a constant failure for almost 2500 years at a minimum, except they haven't.

They're just being young people full of dreams and ideals and they want things just like you did when you were young.

Just because the internet has made information more digestible, easier to learn etc, doesn't mean they don't work, try, and somehow deserve the knowledge less than anyone else.

ok end rant.

~Phil

[bepone]

practice, practice, not philosophy.. i said..