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Lets Talk Distortion !!!!

5/3/1999 9:52 PM
Doug	Lets Talk Distortion !!!! Okay, I have a few questions here. Need to get a few things straight. 1. "Brown" distortion- what is it and how is it created? 2. Saturation- This is where your device reaches its peak flow point, correct? 3. Overdrive- This is when you begin clipping your device? 4. "Grind"- This is complete total clipping right? Now, which sounds better and why? Which harmonics are generated here, and which are more pleasing? Lets provide examples and compare them. Also what is starved plate? is this akin to the brown sound? Thanks, Doug

5/3/1999 9:52 PM

Doug

Lets Talk Distortion !!!!

Okay, I have a few questions here. Need to get a few things straight.

1. "Brown" distortion- what is it and how is it created?

2. Saturation- This is where your device reaches its peak flow point, correct?

3. Overdrive- This is when you begin clipping your device?

4. "Grind"- This is complete total clipping right?

Now, which sounds better and why?
Which harmonics are generated here, and which are more pleasing?
Lets provide examples and compare them.
Also what is starved plate? is this akin to the brown sound?
Thanks,
Doug

5/4/1999 6:10 AM
jason	doug, Starved plate is usually what they call it when they use a tube for the distortion and run the plate off some low voltage(12-24v). As far as which sounds better...I think it depends on the person and the music style. I usually think of overdrive as a more bluesy type of distortion. As far as saturation, I usually think metal type music.

5/4/1999 8:33 AM
R.G.	There aren't any definitive answers to your questions. There has been a lot of discussion of these things before, here and in other places. 1. "Brown" anything is the term musicians tend to apply to a pretty heavily treble-limited tone, perhaps a little mid-range-y. Beyond that, there isn't a clear definition - or rather, you'll find about as many definitions as people. You can "brown" almost any tone by treble limiting it. 2. "Saturation" has multiple meanings. When you're talking about transistors or tubes, it means when the device can't be driven to any more current flow; that is, the current is limited by something outside the device. In reference to distortion, it means that the sound is already as fully clipped as the circuit can make it and any more gain, drive, input drive, etc. will not make it any more clipped. 3. "Overdrive" is taken to be the region where the input signal is larger than the circuit can handle without inducing some distortion, but is taken to be less than obvious distortion by some people, and any amount of distortion by others. In advertising, it just means distortion. 4. There is no generally accepted definition of "grind" other than a harsher more heavily clipped sound. Which sounds better? To whose ears? (That is a serious comment, by the way.) Which harmonics are generated? It's impossible to say from those words. The words are not definitive enough. Words like symmetrical vs asymmetrical clipping, transfer function, relative sharpness of clipping knee, and so on can be linked to harmonic spectra in some ways. You might want to read, among other things, the Guitar Effects FAQ section on Distortion 101 and Russell O. Hamm's paper on "Tubes Vs. Transistors - Is There a Difference" for some discussion of what harmonics and which is better. Hamm's paper in particular gives a very good run down on what harmonic gives what tone to the sound, in easy to understand musical terms. "Starved Plate" is the term for running a tube at very low currents and voltages. It is not a synonym for "brown sound". At very low currents and voltages, tube plates have a very different sound than they do at more normal voltages and currents, higher distortion and different harmonic spectra.

5/4/1999 8:33 AM

R.G.

There aren't any definitive answers to your questions. There has been a lot of discussion of these things before, here and in other places.

1. "Brown" anything is the term musicians tend to apply to a pretty heavily treble-limited tone, perhaps a little mid-range-y. Beyond that, there isn't a clear definition - or rather, you'll find about as many definitions as people. You can "brown" almost any tone by treble limiting it.

2. "Saturation" has multiple meanings. When you're talking about transistors or tubes, it means when the device can't be driven to any more current flow; that is, the current is limited by something outside the device. In reference to distortion, it means that the sound is already as fully clipped as the circuit can make it and any more gain, drive, input drive, etc. will not make it any more clipped.

3. "Overdrive" is taken to be the region where the input signal is larger than the circuit can handle without inducing some distortion, but is taken to be less than obvious distortion by some people, and any amount of distortion by others. In advertising, it just means distortion.

4. There is no generally accepted definition of "grind" other than a harsher more heavily clipped sound.

Which sounds better? To whose ears? (That is a serious comment, by the way.)

Which harmonics are generated? It's impossible to say from those words. The words are not definitive enough. Words like symmetrical vs asymmetrical clipping, transfer function, relative sharpness of clipping knee, and so on can be linked to harmonic spectra in some ways.

You might want to read, among other things, the Guitar Effects FAQ section on Distortion 101 and Russell O. Hamm's paper on "Tubes Vs. Transistors - Is There a Difference" for some discussion of what harmonics and which is better.
Hamm's paper in particular gives a very good run down on what harmonic gives what tone to the sound, in easy to understand musical terms.

"Starved Plate" is the term for running a tube at very low currents and voltages. It is not a synonym for "brown sound". At very low currents and voltages, tube plates have a very different sound than they do at more normal voltages and currents, higher distortion and different harmonic spectra.

5/4/1999 1:46 PM
nic	Brown sound!!! I think it is sort of a 'synthesia' type thing. I have heard most musicians (and artists) tend to have mild cases of it. nic

5/4/1999 3:14 PM
Jim S.	I've heard plenty of guys get a "brown" sound. Playing guitar in front of an audience is the vehicle they use for generating lots of excre- (oops, I mean excite-) ment!

5/5/1999 10:59 AM
Mark Hammer	Re: Brown As I understand it, the origins of the moniker "brown sound" come from descriptions of Eddie Van Halen's tone on the earliest VH albums. In them days, Eddie attained his tone, in part, by use of a Variac to alter the working voltages of his tube amp. It is my understanding that he no longer does this, and that it is not a recommended procedure in any event, since it reduces the life expectancy of the amp. Now that Eddie has the money, and others have the same tastes, many of the brownish features can be built in, without jeopardizing the amp. Although use of a Variac will affect ALL the working voltages in the amp, the most robust effect will likely be in terms of the functioning of the power tubes, with respect to their plate voltages. This, and the interaction with the output transformer, are largely responsible for brownish tone. The rolloff produced by use of a bridge humbucker, 12" speakers, a saturated transformer, and a pair of power tubes pushed past their normal operating conditions, all conspire to produce an overdriven sound which is chalk full of lower-order harmonics, without all the buzzy high end. Basically, we're talking about something which is analogous to what a TS-808 does (soft clip and rolloff), although certainly not how it sounds. Bottom line is that "true" brown is an amp thing, not a pre-amp thing.

5/5/1999 10:59 AM

Mark Hammer

Re: Brown

As I understand it, the origins of the moniker "brown sound" come from descriptions of Eddie Van Halen's tone on the earliest VH albums. In them days, Eddie attained his tone, in part, by use of a Variac to alter the working voltages of his tube amp. It is my understanding that he no longer does this, and that it is not a recommended procedure in any event, since it reduces the life expectancy of the amp. Now that Eddie has the money, and others have the same tastes, many of the brownish features can be built in, without jeopardizing the amp.

Although use of a Variac will affect ALL the working voltages in the amp, the most robust effect will likely be in terms of the functioning of the power tubes, with respect to their plate voltages. This, and the interaction with the output transformer, are largely responsible for brownish tone. The rolloff produced by use of a bridge humbucker, 12" speakers, a saturated transformer, and a pair of power tubes pushed past their normal operating conditions, all conspire to produce an overdriven sound which is chalk full of lower-order harmonics, without all the buzzy high end. Basically, we're talking about something which is analogous to what a TS-808 does (soft clip and rolloff), although certainly not how it sounds.

Bottom line is that "true" brown is an amp thing, not a pre-amp thing.

5/5/1999 2:06 PM
Doc	It's known that vacuum tubes generally become more linear as their operating voltages are raised. Power stages can definitely sound harder and brighter when run at high voltages, and sound softer, less defined, sometimes rougher (and of course more easily saturated or overdriven) when circuit operating voltages are reduced. I don't really know the origin of the description "brown" sound, but I believe you're right about the association with EVH. They do refer to a deficiency or partial reduction of supply in electrical power as a "brown-out", kind of similar to reducing operating voltages on an amp. There's a lot of advice floating around that would lead one to believe that using a variac is prohibitive and damaging to an amp in all cases. Although EVH was reducing his incoming line voltage to get that famous brown sound, he's also a known tinkerer. I'll bet that he was eventually experimenting with raising the voltage, far above the nominal rated line voltage of the amp. That's what will destroy an amp. You know how amps sound great right before they blow up? I'd be glad to have someone explain to me how running a 120v tube amp at 85 or 90 volts will ruin anything other than possibly reducing the emissive efficiency of some tube cathodes. I think the use of a variac is safe for the undervoltage condition.

5/5/1999 2:06 PM

Doc

It's known that vacuum tubes generally become more linear as their operating voltages are raised. Power stages can definitely sound harder and brighter when run at high voltages, and sound softer, less defined, sometimes rougher (and of course more easily saturated or overdriven) when circuit operating voltages are reduced.

I don't really know the origin of the description "brown" sound, but I believe you're right about the association with EVH. They do refer to a deficiency or partial reduction of supply in electrical power as a "brown-out", kind of similar to reducing operating voltages on an amp.

There's a lot of advice floating around that would lead one to believe that using a variac is prohibitive and damaging to an amp in all cases. Although EVH was reducing his incoming line voltage to get that famous brown sound, he's also a known tinkerer. I'll bet that he was eventually experimenting with raising the voltage, far above the nominal rated line voltage of the amp. That's what will destroy an amp. You know how amps sound great right before they blow up? I'd be glad to have someone explain to me how running a 120v tube amp at 85 or 90 volts will ruin anything other than possibly reducing the emissive efficiency of some tube cathodes. I think the use of a variac is safe for the undervoltage condition.

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