Tube Screamers... fuck me.
I'll try to keep this brief, and inevitably fail miserably - so if you have a less-than-average attention span (or worse), the moral of this story is:
Tube Screamers: good; repeated questions about Tube Screamers that have already been answered: bad. Curiosity: good (it may have killed the cat, but they never said it was the cat's curiosity...); complete failure to search for information that would answer your question before asking it: bad.
Now, for the rest of you, I'll try to keep the language varied enough (Ha. Ha. Guess what that means, improperly-educated twatsnagglers of unsavory stock. Ha.) to help facilitate a quick search through this if you're really in a rush... or you really hate this but your friend is on Who Wants To Be A Millionaire Marrying A Washed-Up Celebrity: Detroit Edition and used his Phone-A-Jackass-I-Once-Worked-With to ask you how to spell 'potentiometer', or something else of the sort.
I'm going to try to cover as many bases as I can – basic workings of the Tube Screamer, basic uses of the Tube Screamer, not-quite-so-basic workings of the Tube Screamer, different versions of things once called Tube Screamers, less-basic uses of the Tube Screamer, mods to be performed on the Tube Screamer, bizarre uses of the Tube Screamer, and the like. This won't be completed the first time through, so I'll be updating it a paragraph or two at a time, and this won't be updated without new and interesting questions, so if you think you have an original question, ask. Clear? Hooray. Now, I'm going to be pulling questions from here and there, and most likely copy-and-pasting answers and such straight from the forums, so I thank you in advance for not being a whiny little snot when your question is immortalized in a FAQ maybe five people will read.
Okay, first things... looks like fifth, no? Well, we'll pretend it's first. The most basic use of a Tube Screamer is as a projectile – guitarist out of tune, drummer off the click, bassist... being a bassist, whatever, the Tube Screamer, in its rugged boxy glory, is a formidable for telling people that you mean business. For this, among other things, I have to say that I prefer the Ibanez TS-7 because of its solid box and neat little knobs that can be pushed in and out to make accidental bumps of the knobs harder – I like to push the knobs out before I throw it at something just to see if I can push them all back in when the target is hit, but there are other fun games to be played, like 'Pin The Settings on the Forehead' or (with the help of cables and a take that you really don't need anyway) 'Randomly Engage Pedal While Swinging Maniacally Mid-Recording (and See How It Sounds!)' when you get really bored. Granted, not the most basic use you were expecting, but... hopefully you didn't think you knew everything, because I did say most basic and this is about as basic as it gets. Animals have been using weapons since that first time one monkey knocked another monkey in the head and discovered that he could now take his bananas much more effectively, and unless we want the world to be taken over by awful musicians who can't keep track of their own bloody heads we had better not lose that instinct.
The first thing that touches a signal entering a TS is the input buffer. This doesn't do much but make sure that the source isn't too loaded – in guitarist-speak, it takes the pickup's coat and hat, makes it a nice cup of coffee, and sits it in front of the fireplace while the rest of the pedal gets dressed, so it doesn't get shy and nervous and start acting strange. This kind of input buffer is what's used in front of wah pedals or other non-guitar-friendly sources to stop the phenomenon known as 'loading', or more eloquently 'tone-sucking', as much as possible. Hell, it's not uncommon to take something of the sort and just shove it in front of a wah pedal, or build one into a guitar, to make life easier... but that's neither here nor there. Now, it's good to know that if your input goes into the box, whether the thing is engaged or not you're getting the full benefits of the buffer. If this bothers you, use a true-bypass box around the TS, or mod the TS to be true-bypass, but I see no reason why it should be a bother unless you really like the sound of a loaded guitar pickup. Now, if you think your TS needs more gain, upgrading the transistor and changing a few other things will do the trick here, but the next part of the circuit is designed to do just that so there's really not much point. You could also raise the input impedance by raising the value of the 510K resistor (pull one end out, put another resistor in the hole, solder it down, and then solder the resistors together), but this doesn't seem to be too necessary, so there's little to be gained by fucking with the buffer, apart from learning a little more about how it works and what it does.
The next thing to come is the clipping circuit – this pedal doesn't fuck around. The basic principle behind distortion is 'amplify too much now and go Bunyan on the forest later', and the TS is only a few steps removed from the most basic implementation of this. The way it used to be done was simple: crank the shit out of things. Eventually a point came when some part of a circuit couldn't handle any more, and it would start lopping off the top and bottom of the waveform... think of it like sitting at one of those old lie-detector thingamahowzits with the needle that goes back and forth when the box thinks you're full of shit, and being asked by your ex's father (who is holding a baseball bat and looking pissed as hell) why she started limping after that trip to the coast and why she won't go to Wal-Mart anymore: the needle can only go so far before something is in its way, so it stops at the edge and doesn't come back across until the input tells it to back off. If a component can't handle what's coming into it, it'll reproduce the middle as faithfully as it can between being flat at the top and bottom. That's why people bought treble boosters and hot pickups and other such nonsense before gain knobs were the in thing.
Now, somewhere along the way people decided that just overloading a thing or two was too simple, or too unpleasant, or not bizarre enough to warrant dozens of unnecessary patents to ensure a comfortable retirement should anyone decide to try anything new in the next few decades. Clipping circuits started popping up left and right, and one of the 'classic' designs (like the one used here) is to use an opamp with a diode pair in the feedback loop. What this means, long story short, is that we've got ourselves a little toy that likes to change its gain depending on what's going into it. Now, a diode is like a pissed-off traffic cop – it only wants things going one way, and it'll keep too many things from going that way if it has to. At any cost. Not 'it'll write a traffic ticket' kind of pissed-off, we're talking 'completely eradicate driver, passengers, and vehicle instantly and without question or regret' kind of pissed-off. So if we want to have a signal of consistent 'size' (like traffic of a given density) coming out, what do we do? We shove way too many fucking people both ways, put a blue in each direction with a rocket launcher, and watch the carnage ensue. The gain stage starts by amplifying the signal by, roughly, factors between 10 and 100, and then it gets mangled down to a clipped signal on the way out. As a result, the signal's 'edges' tend to be more flattened-out, which gives us two things: a sort of compression (because where before soft was soft and loud was loud, now soft is loud and loud is fuck-me-that's-so-loud-it-has-to-be-squashed-back-down-to-fit) because of the amplification and resulting traffic armageddon, and a 'buzzy', 'fuzzy', 'hairy', 'grainy', 'overdriven' sound because the transition between 'peak' and 'not peak' is an 'edge' or a 'cliff' instead of the smooth curve that went into it
That's the bulk of it, so I guess we could st- okay, no, there's something left out. I wasn't going to tell you until I thought you were old enough to handle it, but... actually, wait, that's not how this one starts off. Anyway, there's a little thing in the clipping circuit that softens this edge – it's a small capacitor, which you could look at as a sort of 'holding cell' for charge, and what it does is smooth the sound out with its charge-storing goodness... it's like when little kids in art class rub over a crayon/pencil drawing with a tissue to smooth out the rough edges. As the drive knob gets turned up more, this effect becomes more pronounced, so while there is definitely more clipping going on with the drive knob the softening is going on more, so it doesn't seem like it's been cranked as much as it has been if you're listening for 'buzz' - but there's more compression than you'd think there would be.
There's another little cool feature in here that seems to some people to be the entire reason for using one of these – the low-end rolloff. If you're using a TS on its own, you might not want it – you might want a good, tasty crunch with some ass to swing around, and this wouldn't be for you – but if you're boosting an amp this will kick its shit into submission faster than you can say “Bow to your knees – and repent, if you please”. Actually, probably quite a bit faster than that. Oh well. Anyway, this mid hump comes from a resistor and a capacitor that tell the op amp what to sugar up and what to send home alone. Everything above about 700Hz or so gets itself some lovin', but the lower something is below that, the less gain – and, as a result, distortion – it'll get. What does this mean? No more distasteful splatter out of your amp on those chugga-chugga bits, angry sneery nonsense, or flubby low end. Hell, if you use it right this pedal is Gas-X, Midol, and fucking amphetamines all rolled into one.
Okay, so... 720Hz sounds like what? I don't fucking know. Pull a clean track of a guitar, and shove an amp sim in front of it. Then, shove an EQ before the amp sim and crank down everything below 720Hz by about... I don't know, somewhere between 10 and 20 db an octave. Hell, if you want, shove the EQ after a distorted track and see if that tells you more about that range – it might. Depending on my mood, it sounds to me like either the 'cheap AM radio' frequency or the 'this is where feedback starts coming in with a cranked stack, a pissed-off JB in the bridge, and a complete disregard for noise ordinance', which probably doesn't say much for anyone else. Hell, it's probably safest to just call it the middle of the lower mids. Now, don't worry – the low end doesn't completely disappear, it just has a much stronger midrange to contend with. The midrange is more prominent, as well as more compressed. This is good. It makes our amps happy. It's why this thing is so bloody useful. Love it.
Here's where things get simpler. You can relax now. It starts off with a simple low-pass that starts cutting things above about 720. Not too much, but it does result in a noticeable hump – this is good for the amp too. Unlike the previous slice-and-dice, which killed lows in favor of a tighter, more controlled sound, this rolls off higher stuff to make the sound seem 'fatter', and the amp gets to focus more on the mids – which I shouldn't need to say are the range that we want our amp to be focusing on, because licking the head and toes of the signal isn't going to get us anywhere nearly as fast as going straight for the midsection. After this, the tone knob either rolls off or adds high end, depending on where the knob is set, and that's really all there is to it. The volume knob is as simple as it gets – turn up, volume bigger. If you or anyone you know has trouble with a volume knob, make sure to have a steady loop of 'Breathe in... breathe out... breathe in... breathe out' playing with the click track just to reduce the likelihood of stupidity-induced asphyxiation.
This is where the TS9 and TS808 are different. They're really not that different at all, and it takes work to notice a substantial difference between the two – I've seen enough people arguing over which one is brighter and which one is smoother to become fully convinced that all but maybe five guitarists on the planet are entirely and irreversibly full of shit.
Long story short, we have compression, a tiny bit of 'crunch', and a spiked midrange that wants to make its presence known. Neat, isn't it?
Put it in front of the amp, with low gain, tone wherever you think it sounds open but not harsh, and about unity gain. We're not looking to have it boosting things – that's what the gain knob is for. We're looking to have the pedal tighten the sound, compress and juice the mids somewhat, and clean up the high end. That's it.
Now... modding ideas, all over the fucking place. The first place to start is obviously going to be the diode pair. The diode pair, as we said earlier, is the pair of traffic cops raining fire and brimstone on 34th street. What happens if we make them more lenient? More traffic comes through – less compression, less crunch, more output. What happens if we tell one of them to tighten his shit up and the other to cut back a bit? Asymmetrical distortion – arguably the one and only reason why the Boss SD-1 has been allowed to live this long, it sounds more 'natural' to many and allows different harmonic content to show through. What happens if we tell the traffic cops to go to hell? They stop regulating – total fucking chaos. What happens if... okay, you get the picture, cap'n. One common mod is to replace one diode with an LED (say, the LED that tells you when your pedal is on – don't worry, they usually replace it with a cooler one) and thus get different harmonics popping through and a little more volume. If you match the diodes right, you can get more even-order harmonics through – this will make the sound more similar to the clipping of a tube. Yes, that's right – solid state distortion like a tube. Bite me.
Another thing to go for is the range of the mid spike – remember that resistor and capacitor that sat around by the op-amp and kept the lows down? You don't want to do this to a pedal that sits in front of the amp and tightens things up, but for a pedal used on its own as the primary distortion unit there's a little trick to increasing the bass response – replace the capacitor with a bigger one. Right now, it's a .047uF cap, and you can switch it out for a .1uF, or put a .1uF in parallel with it (parallel means that the components are 'side-to-side', both connected to each side directly, while series means that one's front end is tied to another's rear end – capacitor values add when they're parallel and do funky shit* in series; resistor values add in series and do funky shit* in parallel) for .147uF – bigger numbers mean more bottom. Wouldn't go smaller, though, that would just sound a bit nasal and bizarre. If you really want to, though, put in a smaller capacitor.
You can also go between a TS9 and TS808 if it really makes that much of a difference to you. Two bloody resistors in the output buffer are all it takes to go between the two, and pictures will shortly be up to show what they are and how to change them.
Finally, the chip can be yanked out and replaced with very little effort. Find the little black box that has something to the effect of 'JRC 4558D' or 'RC4558D' or 'something-4558-somethingelse' (note that some RI TS9 and TS9DX pedals have a something-75558-somethingelse chip, which is easily the first chip I'd want to replace, and others still have something-2043-somethingelse chips that don't need to be burned in the fires of hell quite as much), yank it out, remember its orientation, and put in an IC socket (they cost pocket change at Radio Shack, and they make chip swapping a matter of moments instead of desoldering and soldering) – you can put any of approximately three gajillion chips in just for the hell of it. The 4558, the 'original' (but not really) op-amp used in the Tube Screamer, was cheap as hell and easy to work with – it's hardly a 'holy grail' of tone, it's just the cheap shit that was available when the pedal started being made. A while back companies started putting other chips in. Some were great, some were terrible, and the terrible ones were terrible enough to warrant a 'New Coke' backlash that got 4558s right back where 'mojo'-obsessed self-righteous snobs thought it should be. Try an OP275, an OPA2134, or an LM833 if you're feeling adventurous and wouldn't mind your pedal suddenly becoming better in every way. I think this is something people should try much more often.
Thus ends the first attempt at this bloody mess. Any questions?
Jeff
I'll try to keep this brief, and inevitably fail miserably - so if you have a less-than-average attention span (or worse), the moral of this story is:
Tube Screamers: good; repeated questions about Tube Screamers that have already been answered: bad. Curiosity: good (it may have killed the cat, but they never said it was the cat's curiosity...); complete failure to search for information that would answer your question before asking it: bad.
Now, for the rest of you, I'll try to keep the language varied enough (Ha. Ha. Guess what that means, improperly-educated twatsnagglers of unsavory stock. Ha.) to help facilitate a quick search through this if you're really in a rush... or you really hate this but your friend is on Who Wants To Be A Millionaire Marrying A Washed-Up Celebrity: Detroit Edition and used his Phone-A-Jackass-I-Once-Worked-With to ask you how to spell 'potentiometer', or something else of the sort.
I'm going to try to cover as many bases as I can – basic workings of the Tube Screamer, basic uses of the Tube Screamer, not-quite-so-basic workings of the Tube Screamer, different versions of things once called Tube Screamers, less-basic uses of the Tube Screamer, mods to be performed on the Tube Screamer, bizarre uses of the Tube Screamer, and the like. This won't be completed the first time through, so I'll be updating it a paragraph or two at a time, and this won't be updated without new and interesting questions, so if you think you have an original question, ask. Clear? Hooray. Now, I'm going to be pulling questions from here and there, and most likely copy-and-pasting answers and such straight from the forums, so I thank you in advance for not being a whiny little snot when your question is immortalized in a FAQ maybe five people will read.
Basic Usage
Okay, first things... looks like fifth, no? Well, we'll pretend it's first. The most basic use of a Tube Screamer is as a projectile – guitarist out of tune, drummer off the click, bassist... being a bassist, whatever, the Tube Screamer, in its rugged boxy glory, is a formidable for telling people that you mean business. For this, among other things, I have to say that I prefer the Ibanez TS-7 because of its solid box and neat little knobs that can be pushed in and out to make accidental bumps of the knobs harder – I like to push the knobs out before I throw it at something just to see if I can push them all back in when the target is hit, but there are other fun games to be played, like 'Pin The Settings on the Forehead' or (with the help of cables and a take that you really don't need anyway) 'Randomly Engage Pedal While Swinging Maniacally Mid-Recording (and See How It Sounds!)' when you get really bored. Granted, not the most basic use you were expecting, but... hopefully you didn't think you knew everything, because I did say most basic and this is about as basic as it gets. Animals have been using weapons since that first time one monkey knocked another monkey in the head and discovered that he could now take his bananas much more effectively, and unless we want the world to be taken over by awful musicians who can't keep track of their own bloody heads we had better not lose that instinct.
Technical Description
Before we get to the real functions and workings of the pedal, it'll be very helpful to describe how the circuit actually works. There are many technically-oriented webpages, and a few friendly ones, out there, so if you have more questions they may be answered much better than I could, with neat words like 'electrolytic' and 'noninverting' as far as the eye can see if you're into that sort of thing. I'm also going to describe some basic mod concepts here, just to get the theoretical aspect down before giving out 'solder this here' nonsense later on.Input Buffer
The first thing that touches a signal entering a TS is the input buffer. This doesn't do much but make sure that the source isn't too loaded – in guitarist-speak, it takes the pickup's coat and hat, makes it a nice cup of coffee, and sits it in front of the fireplace while the rest of the pedal gets dressed, so it doesn't get shy and nervous and start acting strange. This kind of input buffer is what's used in front of wah pedals or other non-guitar-friendly sources to stop the phenomenon known as 'loading', or more eloquently 'tone-sucking', as much as possible. Hell, it's not uncommon to take something of the sort and just shove it in front of a wah pedal, or build one into a guitar, to make life easier... but that's neither here nor there. Now, it's good to know that if your input goes into the box, whether the thing is engaged or not you're getting the full benefits of the buffer. If this bothers you, use a true-bypass box around the TS, or mod the TS to be true-bypass, but I see no reason why it should be a bother unless you really like the sound of a loaded guitar pickup. Now, if you think your TS needs more gain, upgrading the transistor and changing a few other things will do the trick here, but the next part of the circuit is designed to do just that so there's really not much point. You could also raise the input impedance by raising the value of the 510K resistor (pull one end out, put another resistor in the hole, solder it down, and then solder the resistors together), but this doesn't seem to be too necessary, so there's little to be gained by fucking with the buffer, apart from learning a little more about how it works and what it does.
Clipping Stage
The next thing to come is the clipping circuit – this pedal doesn't fuck around. The basic principle behind distortion is 'amplify too much now and go Bunyan on the forest later', and the TS is only a few steps removed from the most basic implementation of this. The way it used to be done was simple: crank the shit out of things. Eventually a point came when some part of a circuit couldn't handle any more, and it would start lopping off the top and bottom of the waveform... think of it like sitting at one of those old lie-detector thingamahowzits with the needle that goes back and forth when the box thinks you're full of shit, and being asked by your ex's father (who is holding a baseball bat and looking pissed as hell) why she started limping after that trip to the coast and why she won't go to Wal-Mart anymore: the needle can only go so far before something is in its way, so it stops at the edge and doesn't come back across until the input tells it to back off. If a component can't handle what's coming into it, it'll reproduce the middle as faithfully as it can between being flat at the top and bottom. That's why people bought treble boosters and hot pickups and other such nonsense before gain knobs were the in thing.
Now, somewhere along the way people decided that just overloading a thing or two was too simple, or too unpleasant, or not bizarre enough to warrant dozens of unnecessary patents to ensure a comfortable retirement should anyone decide to try anything new in the next few decades. Clipping circuits started popping up left and right, and one of the 'classic' designs (like the one used here) is to use an opamp with a diode pair in the feedback loop. What this means, long story short, is that we've got ourselves a little toy that likes to change its gain depending on what's going into it. Now, a diode is like a pissed-off traffic cop – it only wants things going one way, and it'll keep too many things from going that way if it has to. At any cost. Not 'it'll write a traffic ticket' kind of pissed-off, we're talking 'completely eradicate driver, passengers, and vehicle instantly and without question or regret' kind of pissed-off. So if we want to have a signal of consistent 'size' (like traffic of a given density) coming out, what do we do? We shove way too many fucking people both ways, put a blue in each direction with a rocket launcher, and watch the carnage ensue. The gain stage starts by amplifying the signal by, roughly, factors between 10 and 100, and then it gets mangled down to a clipped signal on the way out. As a result, the signal's 'edges' tend to be more flattened-out, which gives us two things: a sort of compression (because where before soft was soft and loud was loud, now soft is loud and loud is fuck-me-that's-so-loud-it-has-to-be-squashed-back-down-to-fit) because of the amplification and resulting traffic armageddon, and a 'buzzy', 'fuzzy', 'hairy', 'grainy', 'overdriven' sound because the transition between 'peak' and 'not peak' is an 'edge' or a 'cliff' instead of the smooth curve that went into it
That's the bulk of it, so I guess we could st- okay, no, there's something left out. I wasn't going to tell you until I thought you were old enough to handle it, but... actually, wait, that's not how this one starts off. Anyway, there's a little thing in the clipping circuit that softens this edge – it's a small capacitor, which you could look at as a sort of 'holding cell' for charge, and what it does is smooth the sound out with its charge-storing goodness... it's like when little kids in art class rub over a crayon/pencil drawing with a tissue to smooth out the rough edges. As the drive knob gets turned up more, this effect becomes more pronounced, so while there is definitely more clipping going on with the drive knob the softening is going on more, so it doesn't seem like it's been cranked as much as it has been if you're listening for 'buzz' - but there's more compression than you'd think there would be.
There's another little cool feature in here that seems to some people to be the entire reason for using one of these – the low-end rolloff. If you're using a TS on its own, you might not want it – you might want a good, tasty crunch with some ass to swing around, and this wouldn't be for you – but if you're boosting an amp this will kick its shit into submission faster than you can say “Bow to your knees – and repent, if you please”. Actually, probably quite a bit faster than that. Oh well. Anyway, this mid hump comes from a resistor and a capacitor that tell the op amp what to sugar up and what to send home alone. Everything above about 700Hz or so gets itself some lovin', but the lower something is below that, the less gain – and, as a result, distortion – it'll get. What does this mean? No more distasteful splatter out of your amp on those chugga-chugga bits, angry sneery nonsense, or flubby low end. Hell, if you use it right this pedal is Gas-X, Midol, and fucking amphetamines all rolled into one.
Okay, so... 720Hz sounds like what? I don't fucking know. Pull a clean track of a guitar, and shove an amp sim in front of it. Then, shove an EQ before the amp sim and crank down everything below 720Hz by about... I don't know, somewhere between 10 and 20 db an octave. Hell, if you want, shove the EQ after a distorted track and see if that tells you more about that range – it might. Depending on my mood, it sounds to me like either the 'cheap AM radio' frequency or the 'this is where feedback starts coming in with a cranked stack, a pissed-off JB in the bridge, and a complete disregard for noise ordinance', which probably doesn't say much for anyone else. Hell, it's probably safest to just call it the middle of the lower mids. Now, don't worry – the low end doesn't completely disappear, it just has a much stronger midrange to contend with. The midrange is more prominent, as well as more compressed. This is good. It makes our amps happy. It's why this thing is so bloody useful. Love it.
Tone and Volume Knobs
Here's where things get simpler. You can relax now. It starts off with a simple low-pass that starts cutting things above about 720. Not too much, but it does result in a noticeable hump – this is good for the amp too. Unlike the previous slice-and-dice, which killed lows in favor of a tighter, more controlled sound, this rolls off higher stuff to make the sound seem 'fatter', and the amp gets to focus more on the mids – which I shouldn't need to say are the range that we want our amp to be focusing on, because licking the head and toes of the signal isn't going to get us anywhere nearly as fast as going straight for the midsection. After this, the tone knob either rolls off or adds high end, depending on where the knob is set, and that's really all there is to it. The volume knob is as simple as it gets – turn up, volume bigger. If you or anyone you know has trouble with a volume knob, make sure to have a steady loop of 'Breathe in... breathe out... breathe in... breathe out' playing with the click track just to reduce the likelihood of stupidity-induced asphyxiation.
Output Buffer
This is where the TS9 and TS808 are different. They're really not that different at all, and it takes work to notice a substantial difference between the two – I've seen enough people arguing over which one is brighter and which one is smoother to become fully convinced that all but maybe five guitarists on the planet are entirely and irreversibly full of shit.
Long story short, we have compression, a tiny bit of 'crunch', and a spiked midrange that wants to make its presence known. Neat, isn't it?
Usage
Put it in front of the amp, with low gain, tone wherever you think it sounds open but not harsh, and about unity gain. We're not looking to have it boosting things – that's what the gain knob is for. We're looking to have the pedal tighten the sound, compress and juice the mids somewhat, and clean up the high end. That's it.
Mods
Now... modding ideas, all over the fucking place. The first place to start is obviously going to be the diode pair. The diode pair, as we said earlier, is the pair of traffic cops raining fire and brimstone on 34th street. What happens if we make them more lenient? More traffic comes through – less compression, less crunch, more output. What happens if we tell one of them to tighten his shit up and the other to cut back a bit? Asymmetrical distortion – arguably the one and only reason why the Boss SD-1 has been allowed to live this long, it sounds more 'natural' to many and allows different harmonic content to show through. What happens if we tell the traffic cops to go to hell? They stop regulating – total fucking chaos. What happens if... okay, you get the picture, cap'n. One common mod is to replace one diode with an LED (say, the LED that tells you when your pedal is on – don't worry, they usually replace it with a cooler one) and thus get different harmonics popping through and a little more volume. If you match the diodes right, you can get more even-order harmonics through – this will make the sound more similar to the clipping of a tube. Yes, that's right – solid state distortion like a tube. Bite me.
Another thing to go for is the range of the mid spike – remember that resistor and capacitor that sat around by the op-amp and kept the lows down? You don't want to do this to a pedal that sits in front of the amp and tightens things up, but for a pedal used on its own as the primary distortion unit there's a little trick to increasing the bass response – replace the capacitor with a bigger one. Right now, it's a .047uF cap, and you can switch it out for a .1uF, or put a .1uF in parallel with it (parallel means that the components are 'side-to-side', both connected to each side directly, while series means that one's front end is tied to another's rear end – capacitor values add when they're parallel and do funky shit* in series; resistor values add in series and do funky shit* in parallel) for .147uF – bigger numbers mean more bottom. Wouldn't go smaller, though, that would just sound a bit nasal and bizarre. If you really want to, though, put in a smaller capacitor.
You can also go between a TS9 and TS808 if it really makes that much of a difference to you. Two bloody resistors in the output buffer are all it takes to go between the two, and pictures will shortly be up to show what they are and how to change them.
Finally, the chip can be yanked out and replaced with very little effort. Find the little black box that has something to the effect of 'JRC 4558D' or 'RC4558D' or 'something-4558-somethingelse' (note that some RI TS9 and TS9DX pedals have a something-75558-somethingelse chip, which is easily the first chip I'd want to replace, and others still have something-2043-somethingelse chips that don't need to be burned in the fires of hell quite as much), yank it out, remember its orientation, and put in an IC socket (they cost pocket change at Radio Shack, and they make chip swapping a matter of moments instead of desoldering and soldering) – you can put any of approximately three gajillion chips in just for the hell of it. The 4558, the 'original' (but not really) op-amp used in the Tube Screamer, was cheap as hell and easy to work with – it's hardly a 'holy grail' of tone, it's just the cheap shit that was available when the pedal started being made. A while back companies started putting other chips in. Some were great, some were terrible, and the terrible ones were terrible enough to warrant a 'New Coke' backlash that got 4558s right back where 'mojo'-obsessed self-righteous snobs thought it should be. Try an OP275, an OPA2134, or an LM833 if you're feeling adventurous and wouldn't mind your pedal suddenly becoming better in every way. I think this is something people should try much more often.
Thus ends the first attempt at this bloody mess. Any questions?
Jeff
