NighthawkChris Posted March 4, 2019 Author Share Posted March 4, 2019 I guess it wasn't that Tube Screamers weren't first it was that the Malaysian RC4558P Chip, that was used in the MXR Pedal, wasn't used til later in the Tube Screamers. Still trying to find out what Pots... Thanks, L Why don't you post a photo of the potentiometer in question if you must replace it with the rare pot? Even if you don't get that same exact potentiometer, all its function is to vary resistance at the wiper and should sound nearly 100% identical to what you had working before if that is all you are changing - aside from slight tolerances. It is not like you are changing the design... A potentiometer is a very simple passive electronic-mechanical component. It is like guitars with the bumble bee capacitors... Capacitors are capacitors... 2 capacitors of X rated capacitance are just that. It's like asking the question what's more 20 nickels or 10 dimes. Both add up to a dollar. The electrons do not take bias to "vintage" components. If their electrical properties are the same, they will affect the electrons exactly the same new or old like. And we are not getting into tolerances and such here because we could extend that argument that no 2 things that exist in the physical world are 100% identical. Simply saying that I agree with Dub that you will not change the sound enough to notice the difference. There's no magic in these older components. But again, if you change the design - i.e. rated component values, circuit configuration, etc. - then you could possibly notice something change for better or for worse depending on the altercation implemented. That's the only conceivable argument that I could agree with that would alter the output of the pedal. Just trying to help out here. It would be nice if we could all get our vintage designed toys working the way we knew and love them to be. Good luck. Link to comment Share on other sites More sharing options...
Dub-T-123 Posted March 4, 2019 Share Posted March 4, 2019 Why don't you post a photo of the potentiometer in question if you must replace it with the rare pot? Even if you don't get that same exact potentiometer, all its function is to vary resistance at the wiper and should sound nearly 100% identical to what you had working before if that is all you are changing - aside from slight tolerances. It is not like you are changing the design... A potentiometer is a very simple passive electronic-mechanical component. It is like guitars with the bumble bee capacitors... Capacitors are capacitors... 2 capacitors of X rated capacitance are just that. It's like asking the question what's more 20 nickels or 10 dimes. Both add up to a dollar. The electrons do not take bias to "vintage" components. If their electrical properties are the same, they will affect the electrons exactly the same new or old like. And we are not getting into tolerances and such here because we could extend that argument that no 2 things that exist in the physical world are 100% identical. Simply saying that I agree with Dub that you will not change the sound enough to notice the difference. There's no magic in these older components. But again, if you change the design - i.e. rated component values, circuit configuration, etc. - then you could possibly notice something change for better or for worse depending on the altercation implemented. That's the only conceivable argument that I could agree with that would alter the output of the pedal. Just trying to help out here. It would be nice if we could all get our vintage designed toys working the way we knew and love them to be. Good luck. Actually all parts (even of equal value) are not equal. I could go on and on but of course there is a reason the manufacturers make all these different types of caps etc In the context of a distortion pedal it tends to lose importance but that’s not to say there’s no difference Link to comment Share on other sites More sharing options...
NighthawkChris Posted March 4, 2019 Author Share Posted March 4, 2019 Actually all parts (even of equal value) are not equal. I could go on and on but of course there is a reason the manufacturers make all these different types of caps etc In the context of a distortion pedal it tends to lose importance but that's not to say there's no difference I did not say anything false - maybe not clear, but not false. Tolerances and manufacturing variances aside, we are not getting into quality or materials used to construct a passive electronic component. I am an electrical engineer - been working in the field since 2001. My point is that X Ohms is X Ohms, Y Farads is Y Farads... Whatever on this... I do not want to argue, because I gave sound advice and I am sorry that you disagree with my statements. I am not going to question your credibility on the subject as I am sure that you have some very good insight into these projects, but I have a high level of confidence of what I have shared in terms of information in this specific thread is correct. I appreciate your input on this subject, and I agree there will be a very slight variation on the subject, but we are talking about a distortion pedal potentiometer - or a capacitor for a tone circuit on a guitar as another relative example. Now if we are getting into RC circuits where we need a micro-controller to have a high level of accuracy in terms of timing, then I might be inclined change my explanation, but not regarding an electric guitar tone circuit or varying resistance to set gain or whatever on a distortion pedal... If you want more precision, then buy higher quality. Perhaps I should have mentioned this as well to make sure the replacement parts match the intended design values??? Anyhow, once again, thanks for your input. Link to comment Share on other sites More sharing options...
Dub-T-123 Posted March 5, 2019 Share Posted March 5, 2019 It’s possible for us to disagree while maintaining a respectful conversation. My intent is not to be argumentative, but I do disagree with what you wrote (maybe not what you actually meant). I think if you reread your post and think about it objectively as an electrical engineer it is obviously not true. Let’s say we take two 10K 1/2W resistors. One is carbon composition, one is metal film. Both measure exactly 10K. The metal film has higher inductance, the carbon composition has higher thermal noise, the metal film has better temp stability, etc etc Let’s say we take two 2.2uf caps. One is film the other electrolytic. They both measure exactly 2.2uf. The electrolytic has higher series resistance, is polarized, has worse temp stability, and a shorter lifespan. You could even take two electrolytic caps of equal value and say the same The same is true for every single part in a circuit. There is more to a resistor than resistance, there is more to a capacitor than capacitance If a resistor is a resistor, why are there so many types of resistors? If a capacitor is a capacitor, why so many types? I’m sure you realize there are different types of pots as well. If you have DC on a pot in an audio circuit, an electrical engineer chooses a conductive plastic pot instead of carbon to avoid a crackling noise when turning the pot. All of this is important not to overlook in general, which is why I made my point Even in the context of a guitar tone circuit these things can be significant. For example, I built a clone of a Fender 5e3 amp. The way the input of this amp is wired, there is usually some DC from the grid that makes its way onto the guitar pots. This means the pots crackle when you turn them even when the pot is brand new and clean. I could use a conductive plastic pot on the guitar, or I could use a cap between the input and grid to block DC, but the point is that the pot material choice just became significant even in a mundane application As I already stated it is of limited significance in a distortion pedal, but that does not make your comments true Link to comment Share on other sites More sharing options...
NighthawkChris Posted March 5, 2019 Author Share Posted March 5, 2019 Hey Dub, I changed that tactile switch and my Metal X works like a charm just as you said! Bought the higher quality switch from Arrow and I have my beloved pedal back! Thanks for the boast of confidence this pedal is my absolute favorite distortion pedal of all time 😁 Link to comment Share on other sites More sharing options...
Larsongs Posted March 5, 2019 Share Posted March 5, 2019 Why don't you post a photo of the potentiometer in question if you must replace it with the rare pot? Even if you don't get that same exact potentiometer, all its function is to vary resistance at the wiper and should sound nearly 100% identical to what you had working before if that is all you are changing - aside from slight tolerances. It is not like you are changing the design... A potentiometer is a very simple passive electronic-mechanical component. It is like guitars with the bumble bee capacitors... Capacitors are capacitors... 2 capacitors of X rated capacitance are just that. It's like asking the question what's more 20 nickels or 10 dimes. Both add up to a dollar. The electrons do not take bias to "vintage" components. If their electrical properties are the same, they will affect the electrons exactly the same new or old like. And we are not getting into tolerances and such here because we could extend that argument that no 2 things that exist in the physical world are 100% identical. Simply saying that I agree with Dub that you will not change the sound enough to notice the difference. There's no magic in these older components. But again, if you change the design - i.e. rated component values, circuit configuration, etc. - then you could possibly notice something change for better or for worse depending on the altercation implemented. That's the only conceivable argument that I could agree with that would alter the output of the pedal. Just trying to help out here. It would be nice if we could all get our vintage designed toys working the way we knew and love them to be. Good luck. It's at my Amp Techs so I can't take a pic. He didn't say anything about a different Pot changing the Sound. (That was my question). But, it doesn't look like the original one that was on on the Pedal & would even require a different looking Knob. So it might look odd? Thanks for all the feedback... L Link to comment Share on other sites More sharing options...
Dub-T-123 Posted March 5, 2019 Share Posted March 5, 2019 It's at my Amp Techs so I can't take a pic. He didn't say anything about a different Pot changing the Sound. (That was my question). But, it doesn't look like the original one that was on on the Pedal & would even require a different looking Knob. So it might look odd? Thanks for all the feedback... L What type of shaft is on the existing pot? Does the existing knob have a set screw? The existing pot shaft will be either 1/4” (6.35mm) or 6mm, it may be smooth, splined, d shaft, etc That type of knob is commonly available. Even if you couldn’t find a replacement pot with the right shaft (which is unlikely) you could use a different pot with a new knob that looks the same If the amp tech can’t handle that pot, I wouldn’t leave it with him any longer. It’s the most basic of basic repairs, should be nothing confusing about it at all Link to comment Share on other sites More sharing options...
NighthawkChris Posted March 5, 2019 Author Share Posted March 5, 2019 And Dub, no disrespect was intended whatsoever - I appreciate your input on my situation and experience with gear electronics; I highly value your input, and that's being respectful here. I gave a short summation on what I meant, because with electric guitars, the components used are usually inferred to be of a certain flavor. Like a wire-wound resistor is not going to go into a control cavity of a Gibson for the most part... I would expect that to never be the case. For example, I used wire-wound resistors for high current output driver applications when I constructed a load box for an automotive ECU to drive the outputs to their limits for durability testing purposes. And of course electrolytic caps probably do not belong in a vast majority of electric guitars' tone circuits as another example - and that they are polarized which may complicate things. But yes, certain types of even passive type components are intended for certain applications. And I also agree with you that other passive qualities are present in components that are intended to be say purely resistive in this case you mentioned of a metal film resistor having a degree of inductance. Of course a designer should take into account frequency responses and power consumptions into account when realizing a design, but this is getting into more complex designs. I was a bit vague in my explanation, so I suppose yes, it is not entirely true, I'm willing to eat my words as I believed I was giving the best advice I could muster out of my typing. The point I was making is that people with common sense that are replacing their electrical components in their gear will try to find the similar part correctly, not something that has a lot of obvious (especially visual) physical differences. Side note, I was always disturbed with the price of those "vintage" bumble bee caps these days and the people willing to pay for them thinking that they can only get a certain tone out of them without trying a ceramic or some other non-polar type rated at the same value. Yes, there will probably be a difference in the frequency response if you do a spectrum analysis on the stuff, but in general, will anyone really be able to definitively discern these differences? Whatever on this. It's not my money... And hey, if it makes someone feel happy, then go for it. I am not waging a war against them, but I was making a point that you will get negligible noticeable effect I believe. Although, if you look at the general qualitative aspects of these paper caps vs more "modern" types of caps, they differ quite a bit from the "newer" stuff with their dielectric qualities and such. So yeah, different materials in component construction, different qualities. Sort of like the way there will be negligible noticeable effects of "intuitive" component replacement in a distortion pedal. To me though, in the end, I just want things to work. There's more than one way to skin a cat. It can go either way... either better or worse. Try it out and see what works. Components we are referring to aren't costing an arm and a leg - unless you're buying a bumble bee cap, haha! Overall, there is a wealth of components out there, yes, and they are intended for specific functions, but again, the common sense part here is that if someone is to replace a component - resistor, capacitor, pot, etc. - and they get a different manufacturer of that same rated component and same material construction, tolerances and variances set aside, I am willing to bet that the stuff will not be audibly discernible and even behave similarly electrically speaking. I would just make sure that voltage ratings are acceptable too, but with a guitar or 9V battery powered effects pedal, I don't think there will be a lot of current to blow someone's socks off... But I would not be surprised what people can do when they put their mind to it... You DO need to know what you are doing if you start messing with the stuff in these boxes. This stuff gets complicated when we generalize all electronics and I really didn't want to go there, because you know what you're talking about and you know how most general population individuals do not grasp all the concepts of electronics and their functions. There's a difference between guitars and pedals vs say more complicated electronics in music gear such as amplifiers which I do not recommend someone play with if they do not know what they are doing! It's hard to damage a passive electric guitar... But I wouldn't be surprised - again... Best regards Dub, and thanks again for your input. Link to comment Share on other sites More sharing options...
Dub-T-123 Posted March 5, 2019 Share Posted March 5, 2019 Have you built any amps or pedals? That would be cool to share pics and such if you’ve got em My next project is probably going to be a multichannel tube mic pre/DI Btw I didn’t sense any disrespect from you, just didn’t want to seem like I was roasting you. Tricky to get a sense of tone over the internet Link to comment Share on other sites More sharing options...
NighthawkChris Posted March 5, 2019 Author Share Posted March 5, 2019 Have you built any amps or pedals? That would be cool to share pics and such if you’ve got em My next project is probably going to be a multichannel tube mic pre/DI Btw I didn’t sense any disrespect from you, just didn’t want to seem like I was roasting you. Tricky to get a sense of tone over the internet Agreed with the "setting the tone" crap... I have a BSE in Electrical Engineering @ U of Michigan, but these days I do more embedded stuff - micro-controller SW. I have to have a pretty good sense of how hardware functions, but I generally have stayed away from HW design as I am more of the SW guy and have been for the better part of a decade. I work in automotive sector of the market as most engineering opportunities in the better MI metro Detroit area. I have done more generic stuff like switches for load boxes and other testing applications. The only thing I did years ago when I was in my early education days was to build a guitar amp that had a very clean-low distortion preamp with op-amps to feed into a processing unit - which in turn was outputted to the power amp section. I was primarily responsible for the preamp design with the team of students. It was very simple - instrumentation amplifier configuration using I believe LM833's (which I chose selectively for the slew rate and unity gain bandwidth for the human audible spectrum). I had a lot of headroom and when I ran the THD sweep on this design, I had very low percentage of distortion reported when I completed the final product. Basically, the power supply that was in the design was not "hit" in the output of the op-amp intentionally to obviously avoid clipping where the distortion starts to come in. It was in an electronics course as you might figure - one of the first ones I completed early in the program. The intention I believe back then we agreed upon was to have the processing unit provide the distortion effect - like some VST plug-in being applied I believe... It was years ago, so I just don't remember all that clearly. My main curriculum was about control systems, digital communications, embedded systems, things that involve a lot of math and science. We had labs and such that had plenty of hands-on stuff, but that's school stuff. As I mentioned, I'm more a SW guy these days, so I just need to know how to drive the stuff from a logical perspective. I wish that I could delve more into the analog world of guitars and effects, but man, I need to pay the bills, haha! I do find it extremely interesting to understand the designs of musical electronic gear though... Most things these days are "smart" (stupid!) though, so there is a demand for SW guys where I'm located. I get into operating systems, low level (micro-controller) peripheral drivers, and of course the application strategy (code) that uses these things. I play with compilers, and communication stuff a lot (Ethernet, CAN, still even UARTs to some extent, etc.) One thing I always learned though is you can always be humbled in this field, so I do my best to be critical and objective of myself. Basically, if I am wrong, I'm wrong. That's how we learn. Anyhow, best regards. I BS here a lot, so I'm sure we will converse some more, haha! Thanks again for all your input - I'm super stoked that my Metal X pedal is working SUPER GOOD when I press the footpad. It just works Link to comment Share on other sites More sharing options...
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