Members amp_surgeon Posted November 17, 2007 Members Share Posted November 17, 2007 There have been a number of posts on this forum that claim that only carbon composition can create that classic "tone" - the mojo we all covet in vintage effects. Myths and misnomers have been spread for a long time, and it's high time to set the record straight. There are two fundamental questions we set out to answer. Question: Are carbon composition resistors different from carbon film, metal film, or other resistor types? Answer: Yes Question: Do these difference affect the "tone"? Answer: No If the answer to the second question is "no", then why do so many people claim that only carbon composition have the classic "tone", while newer resistors types lack that tone? Why do they throw around intimidating terms like thermal noise and voltage coefficient of resistance? Are these terms real, and are they really something which engineers take into account when designing effects (or should be taking into account)? The answers to these questions are complex, so let's get started. Thermal Noise The term thermal noise refers to the noise which is inherent in any type of resistor. This is white noise which increases with resistance and temperature. It was first discovered by John B. Johnson and described by Harry Nyquist in the late 1920's, and so is often referred to as "Johnson-Nyquist noise". There is a good Wikipedia article on Johnson-Nyquist noise here. Does thermal noise affect the tone? Yes, any form of noise will affect the tone. Does it affect it in a "good" way? No. White noise only adds hiss, but no pleasing harmonics. Do carbon compositions offer more or less thermal noise than other types of resistors? No. Thermal noise is a function of the resistance and temperature, and is not affected by the composition of the resistor. Take a look at the formulae in the Wiki article (yeah, I know - makes my head spin too). Nowhere is the resistive material factored into these equations. Since thermal noise is generally a "bad" thing, is there anything engineers can do to reduce thermal noise? Yes, they can use smaller value resistors, and keep the operating temperatures as low as possible. One way to keep the temperature down is to use resistors with a power (wattage) rating well above what's needed in the circuit. A side benefit of this is that it reduces another form of noise, as you'll soon discover. Summary: Thermal noise is the same in all types of resistors, and varies with resistance and temperature. It does not vary with frequency. So, are there any other types of noise which resistors are responsible for? Yes, so let's move on to... Shot Noise Consider that electricity consists of the flow of sub-atomic particles called "electrons". You can compare this to a bunch of bb's flowing down a garden hose. Let's consider the situation when the current flow is low. You can measure the average number of bb's that flow through the hose in a given amount of time, but does this mean that the actual number of bb's in the hose at a specific point in time will be equal to the average? No. The number of bb's will vary, sometimes higher and sometimes lower than the average. Some of the bb's will clump into bunches and others will roll through independently. One thing is for certain - they won't line up like little soldiers and march down the tube in lock step. Electrons flowing through a conductor behave the same way. The sporadic nature of current flow is called shot noise. While shot noise does increase with current, the signal level usually increases faster. Again, for those who like to torture themselves with the math, there is a good Wikipedia article on shot noise here. So, does shot noise only affect resistors? No, it affects all conductors. Does it affect carbon composition resistors more or less than other types of resistors? No, they are all affected in the same way. Can engineers do anything to reduce the amount of shot noise in a conductor? Yes, keep the current level to the minimum required. Ok, this isn't really practical in the power stage of an amplifier, so some tradeoffs are necessary. Summary: Shot noise is the same in every conductor, including resistors, and varies with the current level. It does not vary with frequency. Contact Noise We finally come to a form of noise which affects carbon composition resistors more than either carbon film or metal film - contact noise. Contact noise is often lumped in with thermal noise when discussing different resistor compositions, though they are not the same thing. Contact noise depends on the level of current, the material the current is flowing through (AHA!!!) and the size or cross-section of the conductor. So why do people treat contact noise and thermal noise the same? Because both of them are essentially white noise, and inherent to some degree in every resistor. Carbon composition resistors DO generate more contact noise for a given current than either carbon film or metal film resistors. Does this affect the tone? Sure, any noise affects the tone. Does it affect it in a "good" way? Nope. White noise is broadband, and not predominantly the harmonics we find pleasing. Like thermal noise, it's mainly just hiss. Can engineers do anything to reduce contact noise? Yes. They can keep the current to the minimum required, they can use the maximum size or cross-section which is practical for the circuit (e.g., the "wattage" of the resistor), and they can choose resistor compositions which have the least inherent contact noise. Unfortunately, this is NOT carbon composition. Summary: Contact noise is greater with carbon composition than with carbon film or metal film. It also varies with current and size of the resistor. It does not vary with with frequency. Voltage Coefficient of Resistance Until recently, I'd never even heard of this particular characteristic. Well, maybe I DID hear about it way back in college. If so, then we sure didn't spend much time on it. Nonetheless, there is a lot of discussion about this on a lot of music and gear related sites. If it's so important, I wonder why I'd never heard of it. A little googling revealed the answer - the subject of Voltage Coefficient of Resistance, or VCR, is mainly discussed on two types of sites - those that have something to do with "mojo" tone, and the companies that actually make resistors. None of the engineering sites which I visit regularly ever talk about it. Before we find out why this is the case, let's examine exactly what VCR is. VCR is a coefficient that describes how much the resistance of a resistor will change as the voltage changes. For most engineers, this would be a mind boggling revelation. Resistors actually change value with voltage? What the hell happened to Ohm's law?!? It turns out that it's not as big a revelation as it might seem. The amount of resistance change turns out to be very very small. Take a look at this spec sheet from IBT for their carbon composition resistors. The VCR at 10% of the rated voltage of the resistor is 0.005% per volt. If you subject the resistor to it's full rated voltage, the VCR increases to 0.032% per volt. Let's put this in perspective. If the rated voltage of a resistor were 100 volts (for most carbon comps it's several times this much), then the full battery voltage in an effects pedal would be 9% of the full rated voltage. Using the 10% VCR number, this would be 0.005% X 9, or a whopping 0.045%! For a 100K resistor, this amounts to a ginormous 45 ohms!! Seriously, is 45 ohms going to make a difference in a circuit with a 100K ohm resistor? Well, if we take into account that the rated TOLERANCE for most carbon comp resistors in a pedal is already +/-10%, or 10,000 ohms, I don't see where a difference of 45 ohms is going to have much impact. Bear in mind that this will affect the voltage and current in the circuit by the same percentage - 0.045%. This is how much waveshaping you could expect from VCR. Consider, also, that the actual variance is a percentage, so it will scale down accordingly as the value of the resistor is reduced. This means the variance for a 100 ohm resistor would be 0.045 ohms. The only time an engineer would care about this is if he is designing a high precision piece of equipment, such as a lab measuring instrument. In this case, he would choose the tightest tolerance resistors (0.1% or better), and the material with the lowest VCR. So why do so many mojo sound "experts" spend so much time telling us how important VCR is to achieve that vintage mojo tone? I can't read minds, but I suspect that this is a case where the conclusion preceeded the proof. They had already convinced themselves that vintage parts meant vintage tone, and they were desperate to find some difference (ANY difference) that would substantiate that claim. Summary: Voltage Coefficient of Resistance varies with the composition of the resistor, but it's affect on resistance is far far less than the rated tolerance of the resistors. It can, for all intents and purposes, be considered insignificant as far as tone is concerned. Conclusion There are two significant factors which are different between carbon comps and other types of resistors. These are contact noise, and VCR. Contact noise is detrimental to tone because it's only white noise. The affects of VCR on resistance is so miniscule that it is insignificant. Carbon comps do NOT have better tone than other resistor types. Link to comment Share on other sites More sharing options...
Members skr3ddy Posted November 17, 2007 Members Share Posted November 17, 2007 ... TL/DR Link to comment Share on other sites More sharing options...
Members iluvnoise Posted November 17, 2007 Members Share Posted November 17, 2007 There have been a number of posts on this forum that claim that only carbon composition can create that classic "tone" - the mojo we all covet in vintage effects. Myths and misnomers have been spread for a long time, and it's high time to set the record straight. That was outstanding. Thanks for taking the time and making the effort to sort some of this out, and explaining it so simply. Link to comment Share on other sites More sharing options...
Members SUPER VELCROBOY Posted November 17, 2007 Members Share Posted November 17, 2007 amp_surgeon, are you also echodeluxe? Link to comment Share on other sites More sharing options...
Members mike.sartori Posted November 17, 2007 Members Share Posted November 17, 2007 they look cooler, and that contributes mojo. Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted November 17, 2007 Author Members Share Posted November 17, 2007 amp_surgeon, are you also echodeluxe? Nope, though we are friends. We first met years ago when he discovered, through my daughter, that I have a project recording studio. I've recorded several of his bands in my studio, and now we're both involved in a sideline project to build some repro effects pedals. He's also been learning electronics troubleshooting and repair in my shop. I'm also WAY older than him! Seriously, do you see any similarity between his writing style and mine? He writes like a kid in his early twenties, and I write like your grandfather! Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted November 17, 2007 Author Members Share Posted November 17, 2007 they look cooler, and that contributes mojo. Yeah, I said something along these lines in another post. If your goal is to make something that looks vintage, then use NOS carbon comps, by all means. They aren't going to sound any different than new parts, so why not go for the vintage look? If you think guitarists are anal about maintaining that vintage look, you should spend some time on sites for antique radio and television collectors. I read an article from one antique restorer that described, in painful detail, how to peel the paper cover off of a vintage electrolytic cap, stuff the paper tube with new electrolytics, and then reseal the end caps so that it look JUST LIKE the original antique electrolytic. These guys aren't satisfied that it looks and sounds like the original on the outside - it must also look vintage on the inside! I'm actually in the process of doing this exact same thing with a 1949 Raytheon round CRT television for my sister. Why? She wants to watch her "I Love Lucy" DVD's on it! Link to comment Share on other sites More sharing options...
Members echodeluxe Posted November 17, 2007 Members Share Posted November 17, 2007 TL/DR im pretty sure this means "too long/didnt read" which is funny. i figured you, mr skreddy, would have some awesome conversation to contribute, seeing is that you design and build your own pedals. i guess not... Link to comment Share on other sites More sharing options...
Members Uma Floresta Posted November 17, 2007 Members Share Posted November 17, 2007 they look cooler, and that contributes mojo. I think the metal film resistors look coolest, therefore they contribute more to my psychological tone. (plus they're just better quality all around) Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted November 17, 2007 Author Members Share Posted November 17, 2007 im pretty sure this means "too long/didnt read" which is funny. i figured you, mr skreddy, would have some awesome conversation to contribute, seeing is that you design and build your own pedals. i guess not... Ok, I see. I guess if he wanted to design tube amps, and someone told him that he must read the Radiotron Designer's Handbook (the bible of vacuum tube design) then he'd say it was too long. Or, perhaps he belongs to the group I described - the people who've reached their conclusions and then went searching for evidence to support it. No sense confusing them with the facts. Me - I'm always ready to learn new stuff, and I learn something new pretty much every day. I'll also happily concede when I'm wrong, and I'm wrong as often as anyone else. BTW, I'm delivering an amp to Oakland tomorrow, and getting another dose of Latin fusion. You down? Link to comment Share on other sites More sharing options...
Members iluvnoise Posted November 17, 2007 Members Share Posted November 17, 2007 There will be follow up articles on capacitors and other components. Eventually, I'll get to tubes, where the story is RADICALLY different. Can't wait, man! Thanks again. Link to comment Share on other sites More sharing options...
Members Mrs Phuckingham Posted November 17, 2007 Members Share Posted November 17, 2007 Wow. You two guys spend a LOT of time and energy trying to school us dumb folk into your way of thinking. With your noses that far up in the air, I'm amazed that you can even see us... which brings me to your quote below: Ok, I see. I guess if he wanted to design tube amps, and someone told him that he must read the Radiotron Designer's Handbook (the bible of vacuum tube design) then he'd say it was too long. Or, perhaps he belongs to the group I described - the people who've reached their conclusions and then went searching for evidence to support it. No sense confusing them with the facts. Talking between yourselves about the poster as if he weren't around... . The elitism between you two is astonishing. Echodeluxe made a pompous spam attempt that backfired. Instead of learning from that, you guys are still trying to back it up. The frontman for your operation has no credibility. That is not going to change because we know very well that he doesn't know squat on his own. Which makes me wonder, what do you hope to achieve by teaming up with a guy who has all but killed your project before it even began? Believe it or not, what you're doing has been done dozens of times before. There's nothing new here, just red flags. Link to comment Share on other sites More sharing options...
Members NITEFLY182 Posted November 17, 2007 Members Share Posted November 17, 2007 If you idiots pandered to the people who believe this stuff makes a difference you would probably sell a lot more product. Link to comment Share on other sites More sharing options...
Members Uma Floresta Posted November 17, 2007 Members Share Posted November 17, 2007 http://www.geofex.com/Article_Folders/carbon_comp/carboncomp.htm Link to comment Share on other sites More sharing options...
Members HMKRich Posted November 17, 2007 Members Share Posted November 17, 2007 I'm so confused. Link to comment Share on other sites More sharing options...
Members Mad Hatter Posted November 17, 2007 Members Share Posted November 17, 2007 Ten years later and people are still debating this. Link to comment Share on other sites More sharing options...
Members paperhouse Posted November 17, 2007 Members Share Posted November 17, 2007 what about transistors and caps? i'm sure that the manufacturing process and materials have changed drastically over the years, much more so than resistors. i'd also assume that transistors and caps have a greater overall effect on tone than resistors. echodeluxe said that all new parts sound the same as their vintage counterparts, not just resistors, if i remember correctly. Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted November 17, 2007 Author Members Share Posted November 17, 2007 Believe it or not, what you're doing has been done dozens of times before. There's nothing new here, just red flags. What's your point? That there's no use in doing it at all? Have you seen what a vintage Super Fuzz is selling for on eBay? It's a worthwhile project because nobody else wants to do it, and all of the parts, or suitable subs, are readily available. For us, it's a way to raise some $$$ to pay for the laboratory tube analyzer we want. Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted November 17, 2007 Author Members Share Posted November 17, 2007 what about transistors and caps? i'm sure that the manufacturing process and materials have changed drastically over the years, much more so than resistors. i'd also assume that transistors and caps have a greater overall effect on tone than resistors.echodeluxe said that all new parts sound the same as their vintage counterparts, not just resistors, if i remember correctly. Yes and no. Many transistors are still being made with identical performance specs to the original transistors. These are mainly intended for replacement parts, but they are available in ample quantities for new pedals. Caps are a more complicated subject. Caps have reactance, which makes them inherently frequency sensitive. By definition, they will affect the tone. The questions are the same as for resistors; are there differences in different cap types, and do those differences affect the tone? That's a whole article by itself. I don't know if you're paraphrasing echodeluxe, but the statement is probably an oversimplification. It would be more accurate to say that new parts can be used which will sound the same as vintage parts. This doesn't necessarily mean that all new parts will sound the same as all vintage parts. Some discretion is still required, especially if you're trying to reproduce a vintage design. Link to comment Share on other sites More sharing options...
Members Mrs Phuckingham Posted November 17, 2007 Members Share Posted November 17, 2007 I can't tell if you're playing dumb or not. You wouldn't even be here if it weren't for Echodeluxe's first Super Fuzz spamalicious post that tanked. This thread wouldn't exist if you weren't trying to market in the first place. It's not difficult to get forumites fired up about a pedal. That can be easily used to take advantage of people who don't remember all the times this has happened before. There's something fishy about you guys. Good Karma, retrofx, eroticfx, hempathy, and a dozen others immediately came to mind when I saw your spam. If you doubt the pompous and arrogant thing.. take a look at what your partner has said: since you do not have the electronics backround i do, you lack the proper knowledge of the components to provide me with any information to show me that any of what you say is true. And then read this and follow those links:http://acapella.harmony-central.com/forums/showpost.php?p=24918750&postcount=71 Now does that seem to add up to you? Highly suspicious... and very arrogant. Link to comment Share on other sites More sharing options...
Members paperhouse Posted November 17, 2007 Members Share Posted November 17, 2007 all the parts were hand made by jimi hendrix.to answer seriously, we are using all new components, because everything we need is available in better (more robust) components, and the values are all perfect matches. why use old stuff when the new stuff is better and sounds the same? i think my memory served pretty well, and there was no need to even paraphrase: http://acapella.harmony-central.com/forums/showpost.php?p=24918259&postcount=52 i don't mean to give you a hard time - i was just explaining where i was coming from. i know from experience that my skreddy mayo that uses NOS transistors sounds much much better than any other big muff that i've used (and i've used more than 8 different big muffs). it's not just the tone, but it's how it feels and reacts to my playing. Link to comment Share on other sites More sharing options...
Members echodeluxe Posted November 17, 2007 Members Share Posted November 17, 2007 I can't tell if you're playing dumb or not. You wouldn't even be here if it weren't for Echodeluxe's first Super Fuzz spamalicious post that tanked. This thread wouldn't exist if you weren't trying to market in the first place. It's not difficult to get forumites fired up about a pedal. That can be easily used to take advantage of people who don't remember all the times this has happened before. There's something fishy about you guys. Good Karma, retrofx, eroticfx, hempathy, and a dozen others immediately came to mind when I saw your spam. If you doubt the pompous and arrogant thing.. take a look at what your partner has said: And then read this and follow those links: http://acapella.harmony-central.com/forums/showpost.php?p=24918750&postcount=71 Now does that seem to add up to you? Highly suspicious... and very arrogant. okay well, yeah to be honest, ned got me a little riled up. to take those qoutes from that conversation without any of neds initial flaming does take it a little out of context. the thread was never intended as "spam", only as a sort of market research. you will recall that the thread is asking forumites what they would think of a super fuzz clone. no where in the thread (except for when someone asked what they would go for, and i only gave a ballpark guess as to how much we would sell them for) are there talks or how to order or pricing or anything. the only purpose to that thread was to see if there was ANY market for a good super fuzz clone. now, i can understand that me asking about modding a BMP and then asking about the DMM months prior, and then talking about building pedals would be a tad suspcious. however, i admit that i am learning, (albiet a fast learner ) and i do not know everything. however, you could probably guess that hanging around my friend everyday with his constant spouting of technical jargon (and this guy is an encyclopedia) that i have picked up a few things. but i am NO expert. i apologize if i came off as arrogant, but i feel confident in what i have learned and although my friend is not the last word on any of this, he has certainly done his research and i trust his knowledge. gotta run, but id love to discuss this further. Link to comment Share on other sites More sharing options...
Members Uma Floresta Posted November 17, 2007 Members Share Posted November 17, 2007 i think my memory served pretty well, and there was no need to even paraphrase: http://acapella.harmony-central.com/forums/showpost.php?p=24918259&postcount=52i don't mean to give you a hard time - i was just explaining where i was coming from. i know from experience that my skreddy mayo that uses NOS transistors sounds much much better than any other big muff that i've used (and i've used more than 8 different big muffs). it's not just the tone, but it's how it feels and reacts to my playing. I'm open to the idea of differences in caps and transistors, but I agree with the OP - I think the carbon comp mojo thing is just BS. Link to comment Share on other sites More sharing options...
Members fly135 Posted November 17, 2007 Members Share Posted November 17, 2007 .here's something fishy about you guys. ...And then read this and follow those links:http://acapella.harmony-central.com/forums/showpost.php?p=24918750&postcount=71Now does that seem to add up to you?Highly suspicious... and very arrogant.Sez the person with 3 posts. Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted November 17, 2007 Author Members Share Posted November 17, 2007 It's not difficult to get forumites fired up about a pedal. That can be easily used to take advantage of people who don't remember all the times this has happened before. There's something fishy about you guys. Good Karma, retrofx, eroticfx, hempathy, and a dozen others immediately came to mind when I saw your spam. I don't want to take advantage of anybody. I don't know what those names are, but I presume they are individuals or groups that have ripped somebody off at some point in the past. I have a good reputation with people in the bay area whom I've done work for, as well as people who've bought gear from me around the country. But, I don't expect anyone to take me at face value. You don't know me, and there's no reason I would expect you or anyone else to send me money for a pedal which neither they nor anyone else has ever heard. Neither me nor echodeluxe are trying to sell pedals on this board, or any other board. His intention was only to find a need which we could fill. There are already plenty of 3rd party repros of most of the popular vintage pedals. This was one which people had asked for, and none of the pedal makers stepped up to the plate. If it makes you feel any better, we had planned from the beginning to send a number of pedals out for reviews. We will do our best to select reviewers who are unbiased. If the pedals are not well received, then we won't try to sell them to anyone. If the reviews are good, then we'll open a web site to market them. We don't expect to make a gazillion bucks from these pedals. We're only looking to fund our transition from a shop which, until now, has been primarily focused on repair, to one which has the facilities for R&D work, and eventually manufacturing. If you still think there's anything fishy about this, I'd sure like to know what it is. I'll neither defend nor condemn anything which echodeluxe says. He's a grown man, and he can speak for himself. Link to comment Share on other sites More sharing options...
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