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what creates more noise, the distortion pedal or the overdrive?


mbengs1

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I was wondering since I usually don't need a noise suppressor when using a distortion pedal. but when I put an overdrive pedal before it, the noise level triples or something. maybe overdrives are much noisier than distortion pedals?

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You might be using more drive with the OD.

 

​But the distortion pedal has more gain. I use a DS-1 or a DS-2 usually and the gain is maxed. to get the endless sustain, I set the gain of the overdrive about half way.

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What model OD? If it's that dinosaur you bought, that might be it. Old hissy box. How are the respective levels? I can't think of any other reason other than the noise rides in with the OD not putting out. This could be in the amp settings or the differing spectral content.

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I was wondering since I usually don't need a noise suppressor when using a distortion pedal. but when I put an overdrive pedal before it' date=' the noise level triples or something. maybe overdrives are much noisier than distortion pedals? [/quote']

 

Not necessarily... typically the more gain a device has / adds, the higher the potential for increased noise. However, there are all kinds of variables, so it really depends on the actual circuits we're talking about, and the quality of the parts they used when they did the build.

 

Which specific pedals are you comparing?

 

 

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Not necessarily... typically the more gain a device has / adds, the higher the potential for increased noise. However, there are all kinds of variables, so it really depends on the actual circuits we're talking about, and the quality of the parts they used when they did the build.

 

Which specific pedals are you comparing?

 

 

​umm... I use a boss DA-2 adaptive distortion and the gain on that is about 3 o clock and a super overdrive and the drive on that is at 1 o clock. I get enough sustain with that. I can just vibrato and the note comes out.

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In order to understand the differences you have to understand how they work on the inside.

 

This is a schematic of a Boss Super Overdrive. the bottom half is your active switching which can be ignored.

 

The top half you can follow from left to right. The input feed to Q5 which is simply a 1:1 buffer. That feeds 1/2 of IC 1. This is a gain stage. Above it you see D4, D5 and D6. Those are diodes that clip the signal and give you distortion. Without those all you'd have is a clean boost. There is a drive knob VR1 above which bypasses this drive stage (its incorrectly drawn with a short across its terminals between pin 2&4)

 

The next stage is your tone stack and another (again incorrectly drawn with shorts across the pot terminals 5, 11, 8) The tone pot just shorts the signal to ground with a cap and resistor and rolls off highs like a guitars tone control does.

 

The other 1/2 of the IC boosts the signal back up. After that is your level knob. Again that works like a guitars volume does. Then its fed to Q1 which is a FET. FET's work similar to how a tube works and if its quiet can add some nice tone. Q6 is another buffer and then your output.

 

This is a very simple circuit for drive pedals and is commonly used in many pedals. Simply comes done to the components used, the biasing of components, the order of the stages etc. Boss pedals are not true bypass. The transistors at the bottom in an X configuration are a transistorized latch circuit which work similar to a DPDT switch commonly used in true bypass pedals. The difference is the switch doesn't work when it isn't powered and the two buffers on the input and output are still active when the drive, tone, and level stages are bypassed.

 

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Here is a Boss OD1 which we can compare. to the super. Again if you look at the top half it looks nearly identical to the super. Whats missing is the tone control which consists of 3 parts, A Pot, a Cap and Resistor. There might be differences in how the values or types of components which might make them sound different but there isn't much difference in the design.

 

 

od1-overdrive-schematic.gif

 

 

 

 

 

 

Now compare those to a DS1. Its very similar to an SD1. The bottom switching is identical. If you notice however, it only uses one IC Op amp instead of two halves of a dual op amp. The drive pot adjusts how much gain the IC produces. Then there are 2 diodes afterwards. The gain level of the IC is pushed into the diodes to get the signal to clip. In the others, the diodes are bypassed by the pot.

 

Two different methods of doing something that's similar. The tone and level have no additional gain stage between them like there is on the OD1 or SD1. Q7 FET is still there as is the output buffer.

 

If I were to guess - this design is quieter then the others. Its missing on gain stage so the noise isn't amplified as much. The tone and volume are after the drive stage which tends to muffle high end hiss. How good do they sound compared to each other depends on the instrument used and a players preference.

 

Personally I like using a number of different drives. I typically use a lower gain overdrive first, a Medium drive like a tube screamer second and a higher gain pedal like a Governor third. I place a compressor before all three.

 

771c13a12b30ac47733ce1a21fdb27eb--guitar-pedals-electric-guitars.jpg

 

 

Personally I like using a number of different drives. I typically use a lower gain overdrive first, a Medium drive like a tube screamer second and a higher gain pedal like a Governor third. I place a compressor before all three. I can then combine the amounts of drive for each instead of trying to get one pedal to do it all. I can switch from low to medium to high, I can combine a low with a medium and get a high level drive that's different from the single high. I can use the compressor with the low and get a medium, or with the medium to get a high level drive. and when used with a high I get non stop sustain.

 

Using separate pedals combined is like adding additional gain stages to a single pedal. The key is to watch the gain and noise levels because the noise floor rises with each gain stage added. The quality of the components in the pedals is important too.

 

 

 

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1 Hiss comes from this. Doesn't matter if its a diode, a three layer transistor or a multi layer chip.

Electrons are pushed through silicone. They put additives in the silicone that conduct electricity. Its not metal that conducts all the electrons cleanly, its conductive particles suspended in a non conductive material - silicone (Sand/Glass) One side has more missing electrons then the other (holes) the other side extra electrons. This makes the material conduct electricity in one direction easily, and blocks the the polarity is reversed.

 

In the center you have a layer where the two material are bonded. It takes a minimal amount of voltage to break down that barrier and get electrons to flow.

 

 

diode7.gif

 

 

In order to understand where the noise comes from you have to take things down to a molecular scale, you know quantum physics. If you don't understand anything about atoms and flunked all your science classes then call it FM (Friggin Magic) Otherwise grasp things a bit. It is rocket science but on a very small scale.

 

 

Molecular electronics is what engineers deal with designing chips with imperfect materials now. There is no guesswork since the atomic microscope was invented and they can actually see the movement of electrons through silicone.

 

 

The problem isn't with the design. You can easily design a perfect circuit with a computer that all adds up perfectly. The problem is all in the materials you have to work with. Quality materials have fewer impurities which increase noise levels and there is only so much thay can do to refine the materials before the cost becomes astronomical.

 

Within the diode you have conductive and non conductive materials. An electron has to pass from atom to atom, Hitching a ride on the outer orbit of an atom called the Valence ring.

 

4.-Atomic-structure-of-Pure-Silicon.jpg

 

 

 

 

some atoms have no electrons in that ring (P material) Others have extras (N materials) They have to bridge the distance going from one atoms orbit to the next to cover the distance. The trip isn't a straight line and you have many collisions as these electrons play musical chairs trying to get across.

 

The Hiss comes from these electrons colliding with impurities. Think of it like a pool table. Some balls go straight into the pockets and others hit bumpers and other balls before they get to where they are going. They make noise when they collide. You hear a grainy hiss because there are millions of tiny electrons colliding as they make their way across the silicone (or germanium)

 

maxresdefault.jpg

 

 

Here's another. The atoms are like small planets and the electrons hitch a ride around these atoms in orbits till a spot opens up on the next atom closest in the direction it's being pushed. The go round and round playing musical chairs working their way across the material.

 

 

1.png

 

Not every electron going in one side comes out the other either. If you had a pipe filled with 500 marbles, then pushed the last # 500 in on one side, #1 would pop out the other end.03405.png

 

All electronic components are made of Elements. You could consider the design of components Chemistry as much as you do a separate science. The formulas used in chemistry, and Electronics all fall under the broader heading called physics. You don't need to be a mathematician to understand some of it.

 

A Transistor works like a water tap with electrons flowing. A small turn on the valve lets allot of water through. In an amp a weak signal from a pickup eventually lest allot of power flow through the speaker.

 

transistor-as-faucet.gif

 

 

The only differences a small voltage on the P layer of this transistor creates a bridge so the larger voltage can pass from one N layer to the other. Without a signal being fed to the P layer, no signal is created on the output but because the transistor is biased with a DC voltage there is a DC flow of electrons which do make noise in the form of a hiss. If the signal is amplified over and over, the hiss level rises exponentially.

 

transistor9.print.png

 

 

 

Just know that the electrons are forced to do things which can result in noise, especially when you're abusing the components to intentionally create distortion. Distortion and noise are one in the same. They are not what you call High Fidelity or pure sound so its a matter of degree when it comes to designing circuits.

 

If you use low quality parts, you may be able to build circuits cheaply, but then noise is usually a major issue. You can also buy the best components and there's no guarantee the circuit will be noise free especially when components are being abused and forced to work beyond their parameters as in the case of distortion, overdrive and fuzz circuits. You accept the bad with the bad when you abuse components and hopefully get what you want.

Modular-molecular-electronic-devices-could-have-tunable-functions-via-self-assembling-molecular-stacks.jpg?1440528479

 

W

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I was wondering since I usually don't need a noise suppressor when using a distortion pedal. but when I put an overdrive pedal before it' date=' the noise level triples[/b'] or something. maybe overdrives are much noisier than distortion pedals?

 

Gain = Amplification.

 

Your overdrive pedal does generate some noise. Because it is placed before the distortion pedal, the noise from the overdrive is amplified by the gain of the distortion pedal.

 

Even if the overdrive generates less noise than the distortion, that "less" noise becomes more noise when it is amplified.

 

To determine which one of your pedals generates the most noise, turn them on one at a time and compare.

 

 

 

 

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