Looking for exciter schematics

[The Dark force of dance]

Y-ellow y'all.
	So many people have written to me about this both privately and publicly.
It's pretty scary really considering how peripheral this all is at the
moment. But it has got me thinking.

terry michaels pointed out thusly.

>If Iabc is connected to its input, the LM13600 is multiplying the input by
>itself, and is acting as a squaring circuit.  Squaring a sine wave doubles
>its frequency.   Maybe this is the underlying principle behind the
>"Exciter".

Yup. This sounds about right. As Paul Perry mentioned, an integration
function. Or at least to a certain extent. It would stand to reason. I wish
I had time (And space) to get back inside my anal explorer type C box and
have a poke around. From memory this sounds a vary plausible explanation.
And probably why Aphex say. "Our distortion is better than yours anyway so
nerrr." Followed by. "And if you don't watch out I'll go tell mummy."

Stiff cheddar. I just wanna know what it is that's so special. I could do
with an exciter clone but I'm never satisfied with what some manufacturer
tells me is the limits of my creativity. I wanna mess with this stuff. But
first I wanna know what I'm messing with.

Paul Perry mentioned a friend who had successfully modeled an exciter in
software on a DSP. The thing is that on my last CD I messed with this
process where by I would take the signal, distort it, make a 2 quadrant
wave out of it and then re-modulate the original signal with it. And I was
getting these amazingly analogue sounding recordings even though it was
entirely digital. I was actually trying to go some way to model the
behavior of a "bad" valve stage transient but in hind sight, what I
probably ended up doing was re-creating an aural exciter. But I maintain
that the process is similar.

A long time ago in a list far away we had this discussion about. "Why
exactly do valves sound better if indeed they actually do." What we came
down to was a term we coined called. "Micro-non-linearities". We know the
mechanism by which these random non-linearities occurs and further research
showed me that it was the very thing that designers of vacuum tubes try to
overcome that is the probable cause of these "warming" effects. I've been
trying to get round to building some valve stages ever since. I'll get
there eventually Eric Promise. :) But! I postulated at the time, a very
elaborate scheme by which you could model the process with a transistor
stage as a joke. But it's all suddenly dawned on me that an aural exciter
really just an emulation of the kinds of harmonic distortions (And I use
that term loosely) that a valve stage _can_ introduce without too much
trouble. And I should just make a side mention that if you've ever looked
at the behavior of a 13600 going into clipping, it certainly looks like a
valve does. In that it soft-clips like a class A valve stage.

I guess I should, for the sake of succinctness sum up thusly. We use to use
valves because it was _Thee_ technology. Now we use them because they
somehow "Sound better." Though few of us have a clue to exactly why. So why
is it that we need an Anal explorer? To make things sound better... Bottom
line.

Curious don't you think?

I'm making no value judgements here. I still want to mess with valve stages
a real lot when I get the chance. I've got a bunch of really interesting
glow fets here (thanks Eric) just itching to be messed with. It's just that
it crossed my mind that if all this is the case, then both a valve preamp
and an anal explorer would be playing in the same ball park. Which is
better who knows and who cares, just that it would seem that the inventors
of the anal explorer may have simply stumbled onto the same process,
(different mechanics) as that of a vacuum tube stage. Now if that could
have been proven in the 70s, wouldn't that have blown their little patent
right out of the water. :)

Be absolutely icebox.

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