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Vintage threads from the first ten years

No biggie.

10/14/1999 6:38 PM
R.G.	No biggie. No biggie. No problem.

10/17/1999 6:20 AM
Mark Hammer	Ditto. Your rep as a gentleman remains intact. Y'know, this gyrator thing is pretty darned simple, innit? Strikes me that there are scads of fuzzy gadgets that could benefit from a little pre-distortion eq-goosing. Two well-chosen bands of pre-EQ, 2 well-chosen band of post, a drive, and a volume control, and you got yourself a pretty nifty little box there.

10/17/1999 6:44 PM
R.G.	Yeah, that's kind of where this is leading. There are a couple of threads here, for those that haven't been watching closely. - Pre-distortion EQ is the key to some tones you can't get other ways. Post-distortion EQ is NOT the same thing. - A pre-distortion EQ can be as simple as a knob-adjustable wah circuit from one of the fifty-seven varieties I was recounting in the wah technology article. Some are as simple as a single opamp, some use a radio shack inductor, or gyrator, and some just use twin tees or bridged tees. You can whip up one of these pretty easily, and probably tuck it away inside your distortion box. - More flexibility can be had from some combination of graphic and parametric EQ. This could be as simple as a two-band parametric (six knobs to play with) or as robust as a multiband graphic with a couple of parametrics inserted in critical bands. Aron was asking specifically for trimpots in the graphic and parametric layouts so he could build an embedded EQ pre- and post-distortion. When all is said and done, I suspect that good EQ on both sides of a clipping stage may matter as much if not more to tone than the clipper itself, as long as it's not too offensive.

10/17/1999 6:44 PM

R.G.

Yeah, that's kind of where this is leading. There are a couple of threads here, for those that haven't been watching closely.

- Pre-distortion EQ is the key to some tones you can't get other ways. Post-distortion EQ is NOT the same thing.
- A pre-distortion EQ can be as simple as a knob-adjustable wah circuit from one of the fifty-seven varieties I was recounting in the wah technology article. Some are as simple as a single opamp, some use a radio shack inductor, or gyrator, and some just use twin tees or bridged tees. You can whip up one of these pretty easily, and probably tuck it away inside your distortion box.
- More flexibility can be had from some combination of graphic and parametric EQ. This could be as simple as a two-band parametric (six knobs to play with) or as robust as a multiband graphic with a couple of parametrics inserted in critical bands.

Aron was asking specifically for trimpots in the graphic and parametric layouts so he could build an embedded EQ pre- and post-distortion.

When all is said and done, I suspect that good EQ on both sides of a clipping stage may matter as much if not more to tone than the clipper itself, as long as it's not too offensive.

10/17/1999 10:54 PM
Mark Hammer	Mmm-hmmm. My hunch is that the design characteristics of pre-distortion EQ are somewhat different than those of post. In some respects, what you want in a pre-distortion EQ is a very low to moderately-low Q sweepable section, so that broad bands of fundamentals could push the clipping circuit a little harder. Alternatively, if fixed bands are used, I would think that most of the action is taking place between about 150 and 500hz (at least for guitar), so even with fixed bands, you don't need lots of them. In contrast, at the post-EQ point, you've got all those added harmonics to contend with, so you need something that is a little more "surgical" in function. I think I mentioned it either to RG or on Alt.guitar many years ago, but I like to think of distortion as something like analog subtractive synthesis: i.e., you produce a signal with lots of harmonics, and then generate character by removing those harmonics with deliberate filtering. Although many would think that post-EQ is a simple matter of a 3-band EQ setup (Tr/Mid/Bass), we fail to notice that the design of the device itself often has more complex low-pass filtering along the way, such that there is more than a 3-band or two band (whether separate or panning-type as in the BMP) at work here.

10/17/1999 10:54 PM

Mark Hammer

Mmm-hmmm. My hunch is that the design characteristics of pre-distortion EQ are somewhat different than those of post. In some respects, what you want in a pre-distortion EQ is a very low to moderately-low Q sweepable section, so that broad bands of fundamentals could push the clipping circuit a little harder. Alternatively, if fixed bands are used, I would think that most of the action is taking place between about 150 and 500hz (at least for guitar), so even with fixed bands, you don't need lots of them.

In contrast, at the post-EQ point, you've got all those added harmonics to contend with, so you need something that is a little more "surgical" in function. I think I mentioned it either to RG or on Alt.guitar many years ago, but I like to think of distortion as something like analog subtractive synthesis: i.e., you produce a signal with lots of harmonics, and then generate character by removing those harmonics with deliberate filtering. Although many would think that post-EQ is a simple matter of a 3-band EQ setup (Tr/Mid/Bass), we fail to notice that the design of the device itself often has more complex low-pass filtering along the way, such that there is more than a 3-band or two band (whether separate or panning-type as in the BMP) at work here.

10/18/1999 4:10 PM
Ed Rembold	O.K. guys, After alot more fiddling around, I have this to report, I'm sticking with the bands that i've chosen, not to be stubborn, but just to try to keep it simple. Reguarding pre-EQ , I've found that only "cut" is required no boost, If you pre boost bass , you get Fuzz if you pre boost treble , you get unreal fizz. if you pre boost mids, you get harshness (IMHO). However, precutting bass before clipping and then boosting it after ,is very tasty. same with treble. Ed Rembold

10/18/1999 4:10 PM

Ed Rembold

O.K. guys,
After alot more fiddling around, I have
this to report, I'm sticking with the bands
that i've chosen, not to be stubborn, but
just to try to keep it simple. Reguarding
pre-EQ , I've found that only "cut" is required
no boost, If you pre boost bass , you get Fuzz
if you pre boost treble , you get unreal fizz.
if you pre boost mids, you get harshness
(IMHO). However, precutting bass before clipping
and then boosting it after ,is very tasty.
same with treble. Ed Rembold

10/18/1999 5:10 PM

R.G.

quote:
"I'm sticking with the bands that i've chosen, not to be stubborn, but just to try to keep it simple."

Hey, if it sounds good to you, great - go with it! Mark and I are just theorizing. Reality coalesces out of the clouds of theory.

Simplicity is also something to be striven for. Having three knobs per frequency band in a multiband EQ is great if you're a techie, but not so good for lightning tone changes on stage in a dark smoky bar. Flexibility is another name for complexity, and inflexibility is simplicity carried too far. Elegance is just enough of each.

quote:
"only "cut" is required no boost, If you pre boost bass , you get Fuzz if you pre boost treble , you get unreal fizz.
if you pre boost mids, you get harshness (IMHO). However, precutting bass before clipping and then boosting it after ,is very tasty. same with treble."

I think that this is what the designers of the TS808 and TS9 decided - cut bass and cut treble. Some people perceive this as a midrangey honk, though. It's all in the ear that's listening. There may be some tinkering with the amount of boost that makes the tone vary as well.

Some folks like the sound of a resonant peak pre-distortion with a level such that most of the signal is not distorted a lot but the resonant peak really gets kicked into distortion. I have started thinking of this as Jimi's Wah Trick.

I've been mulling over some other things like moving resonances and cutoffs depending on a sidechain like an LFO, footpedal, or envelope filter so that the distortion character changes depending on the sidechain events. This should add some animation to distorted sounds.

In any case, go with what sounds good to you.

10/18/1999 6:50 PM
Aron	>I've been mulling over some other things like moving resonances and cutoffs depending on a sidechain like an LFO, footpedal, or envelope filter so that the distortion character changes depending on the sidechain events. This should add some animation to distorted sounds. I've been wanting to do this for a long time (but I don't know how). I have often thought that a subtle "phasing" or chorusing or some other envelope controller parameter would add "life" to a distortion pedal. Aron

10/18/1999 6:50 PM

Aron

>I've been mulling over some other things like moving resonances and cutoffs depending on a sidechain like an LFO, footpedal, or envelope filter so that the distortion character changes depending on the sidechain events. This should add some animation to distorted sounds.

I've been wanting to do this for a long time (but I don't know how). I have often thought that a subtle "phasing" or chorusing or some other envelope controller parameter would add "life" to a distortion pedal.

Aron

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