Where to place carbon comp(s)?

Frequently asked question regarding resistors, potentiometers, types, requirements, ratings etc.
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evo
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Post by evo »

Hello All,

Sometime ago i built Fuzz Face (with Late 60's option) Kit from General Guitar Gadgets.
Now, i want to step little further and build another one with components selected by me.

I want to try Carbon Composition resistors and maybe Mallory 150 cap (if it makes sense?)

So my question is where to put carbon comp(s) and where metal films to keep hiss level down?
Schematic http://www.generalguitargadgets.com/pdf ... sc_b69.pdf

(yes, i've read R.G. Keen's "Using the Carbon Comp Resistor for Magic Mojo" but i can't figure out
the points he tells to avoid with cc's)

Thanks beforehand

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Post by madbean »

In general, if I'm using them it's for resistors in series with the path of the signal. For resistors to ground or power, I stick with carbon or metal film. Usually at the input, output or between gain stages is where you might notice a difference; these are the places you will get whatever you can out of them.

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Post by analogguru »

evo wrote:So my question is where to put carbon comp(s) ....
The best: nowhere

analogguru
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Post by puppiesonacid »

analogguru wrote:
evo wrote:So my question is where to put carbon comp(s) ....
The best: nowhere

analogguru
yeah but we're all made of carbon bro... and like... ya'know... b/c of that... the tone of my soul comes through more realistically, b/c everything's made of carbon man and so are flowers and flowers bloom man.....so they make the notes bloom...so you should just go ahead and use them everywhere man... thats how hendrix and jerry played... all carbon comp resistors and so were all thier Marshall amps too, and so were the mixing boards and tube condensor mics that recorded them... ( imagine the best chong impression ever )


really... i get that when building an effect your going for a certain effect and the components in the chain all add up to the end result, but the biggest thing about all of the "exacting science" going into the design, its almost like dog breeding. you take one example of a "great" sounding unit ( biased opinion ) and dissect it down to the millivolt, ohm, henry, mU, what have you... and you reproduce it. but some of the "best effects" ever were made with crap components, or had a certain recording that gave a unique example of how it could sound, but factor in all the other millions of things that could be taken into account and you have to stop and think when your tweakin' your breadboard... "shit... to try and emulate the sound that I heard on this hendrix record, which has been digitally remasterd 1,000x, originally mixed down from tape, and mold grew on them and they cleaned them with a chemical that might have stripped the high end prescene, i think im going to throw a carbon comp resistor in there to make it more authentic sounding" is just fine, it keeps people chasing after the age old "how to turn lead into gold" sort of vibe that surrounds stompbox forums/marketing/namm/guitar magazine gear reviews.

ag is right....right?

it sounds more vintage or less hi fi, because its composition is inferior to and cheaper to make than metal film resistors. do what you want, try it oout, trust your ears b/c we can't hear it for you.

if you reallly want to challeng yourself... systematically figure out how many different combinations of metal and carbon comp resistors you can test out, write them all down and try them out one by one. I bet at the end of the maddening rigor, you wont give a shit if they sound different just as long as they work and the pedal works onstage... if you play onstage.


hope this helps...

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Post by soulsonic »

When I use them at all, I like carbon comps for low values (less than 100K) and metal film for high values. At low values, any noise is negligible.
Many of my recent builds have been a mix of carbon comp, carbon film, and metal film. It's really not a big deal when it comes down to it, but if it helps you find your mojo, it can be a fun way to add spice to your builds.

Overall, I think capacitor types make the biggest impact on the sound. Resistors only make the most subtle changes. Sometimes when it's a critical build, that subtlety can be important, but most of the time most people will have a hard time hearing any difference.
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Post by moltenmetalburn »

The idea of wanting a circuit to sound less "hi-fi" perplexes me. I am always looking for the highest fidelity possible, it is my sound after all were talking about and I would never sacrifice fidelity for MOJO or anything for that matter. Why would ANYONE want a lower fidelity sound, unless were talking about a lo fi type of effect? :hmmm:

It really just seems like a wild goose chase. :shock:
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Post by modman »

moltenmetalburn wrote:Why would ANYONE want a lower fidelity sound, unless were talking about a lo fi type of effect? :hmmm:
Maybe because they are not looking for 'fidelity' to the input signal, but rather 'non-fidelity,' in another word, distortion? Have a look at the Hot Cake thread and the comments on hifi TL071 vs socalled lofi (more noise) 741 opamps...

Remember that all those vintage gems you are drooling over were put together without any regard to component type or rating - as long as it worked. So if you want your own unrecreatable signature distortion or fuzz, use the oldest, cheapes, lowest tolerance crap you can find without any disregard for brands and you might find something great .... or it won't work. But if you are scared to experiment, that's a bigger problem...

Also: the mojo components you are going to order, will it amount to more than $50? If so, you should use the $50 to buy a second hand 15mhz oscilloscope on ebay. Really. IMHO though. Will be money much better spent, so you can really see what is going on and check whether the carbon comp makes a difference...

There are other threads like
Mojo components Debunking thread
Hhigh quaility components: real or myth?
on the same subject.
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Post by evo »

modman wrote: Also: the mojo components you are going to order, will it amount to more than $50? If so, you should use the $50 to buy a second hand 15mhz oscilloscope on ebay. Really. IMHO though. Will be money much better spent, so you can really see what is going on and check whether the carbon comp makes a difference...

There are other threads like
Mojo components Debunking thread
Hhigh quaility components: real or myth?
on the same subject.
Thanks for the links modman. Actually i own oscilloscope but i wanted try out something different and actually hear
the difference (if any) and after that dive little bit deeper into this world of all mojo's...
moltenmetalburn wrote:Why would ANYONE want a lower fidelity sound, unless were talking about a lo fi type of effect? :hmmm:
Well i would, because of feeling...
For example, i never get my mind flowing with any of the line6 devices (and i got plenty of them) VS. my "oldtimer" all knobs full + one simple fuzz i can get it, not always but....
and in that moment, i forgot all that hiss and crap what comes out of speakers....

Of cource this depends what type of music you are playing and blah blah....

Peace
EVO

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Post by Greg »

modman wrote:
moltenmetalburn wrote:Why would ANYONE want a lower fidelity sound, unless were talking about a lo fi type of effect? :hmmm:
Maybe because they are not looking for 'fidelity' to the input signal, but rather 'non-fidelity,' in another word, distortion? Have a look at the Hot Cake thread and the comments on hifi TL071 vs socalled lofi (more noise) 741 opamps...

Remember that all those vintage gems you are drooling over were put together without any regard to component type or rating - as long as it worked. So if you want your own unrecreatable signature distortion or fuzz, use the oldest, cheapes, lowest tolerance crap you can find without any disregard for brands and you might find something great .... or it won't work. But if you are scared to experiment, that's a bigger problem...

Also: the mojo components you are going to order, will it amount to more than $50? If so, you should use the $50 to buy a second hand 15mhz oscilloscope on ebay. Really. IMHO though. Will be money much better spent, so you can really see what is going on and check whether the carbon comp makes a difference...

There are other threads like
Mojo components Debunking thread
Hhigh quaility components: real or myth?
on the same subject.

YES. Hi-fi might seem intuitively best, but if you overdo it you end up with effects that are hard, brittle, harsh and hurt people's ears.
The effects that have a lot of "character" usually target a certain frequency range.. a range that let's the guitar be heard apart from the Bass, Drums and Singer. Too much Bass in the signal and it'll get muddy, too much Treble and it'll get annoying.
It's pretty easy to open up the range of most effects, but the results can sound bad.

The nature of guitar music is not really hi-fi IMO, that's why a guitar doesn't sound good through a pure amplifier, and why older less accurate devices sound better and are more popular.
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Post by RnFR »

guitar speakers are absolutely not "hi-fi." they dump everything over 5k or so. ever try to play your stereo through a guitar amp? not so good.

another thing- with high gain circuits, too many high frequencies can cause oscillation. one of the ways this can be tamed by rolling off high end. so too high fi can be bad in that way as well.

personally, and this is completely subjective, i prefer things that sound lofi and kinda crappy! not really crappy- let's say "colored." most of the music i prefer was made with the minimal technology of the day and i find the old stuff to have more character. i personally can't stand ultra slick production, and i sure don't want the exact sound of my guitar to come out of the speakers- because it would sound like shit. ever heard a electric guitar recorded direct? not very nice. why do you think people use cab sims? to make their sound more "lofi".

anyways, it's all of the softening up of the signal that shapes it into what our ears find pleasing, and this whole thing called distortion is all about lofi!
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Post by dai h. »

IMO swapping resistors for carbon comp is not a real effective (cost, time, effort) way of effecting a tonal change. For a Fuzz Face seems to me the transistors are most important, then circuit values. Maybe if you can get some super cheap (surplus, etc.) and you want to put in the time, etc. to swap and do tests or whatever it might be worth trying (even just to know they don't do much). I don't think there will be much to be gained sound wise compared to using plain cheap carbon film Rs. I have a bunch of c.comp. Some were super cheap surplus, some were not so cheap. After some goofy swapping exercises on efx. and amps I'm left with the conclusion they are not that important. They can look pretty cool, though. :lol:

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Post by moltenmetalburn »

It seems as if when i hear the term hi fi i think only in terms of the fidelity of the signal, what Im gathering is the accepted muso definition for high fidelity is referring to the full frequency response typical of hi fi audio systems. I was thinking people actually somehow favored a degraded audio signal, in this case degraded by additional distortions added by the carbon comps. Definitely clears it up for me.
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Post by IvIark »

Carbon comps won't add any distortion, the only effect IMO is a slight softening of the tone. It's just like everything else, If you like it use them, if not don't bother.
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