Looking for exciter schematics

[The Dark force of dance]

Y-ellow Y'all.
	I had been following this thread with some interest. I have a need to
replace my Aphex Anal Explorer. Oops I mean Aural Exciter and build
something of a clone. It's a back-burner project at the moment but I had
been looking for a schematic for it for some years.

I tried to trace out the circuit some years ago but I couldn't make sense
of it then. It makes more sense now but I have in no-way had time to get
back to tracing the circus. It's a bugger of a job.

Having said that, I know that it works entirely differently to the Circuit
by Jules Ryckebusch. What it appears to do is selectively filter out the
top end, then re-modulate that with it self. It uses an OTA. A 13600.
Actually not a real 13600 but a second source part. I forget the part
number but it amounts to the same thing. The control current input (Iabc)
is fed from the signal source it self. This seems to be a fixed amount but
the source is through the filter. The output of this circuit is mixed back
with the dry signal through the mix pot. I say "Seems to" because I'm not
entirely sure that's exactly how it works.

As best as I can figure it, the audio in the selected frequency band 2
quadrant multiplies with the original signal causing harmonic spikes. The
irony of this is that this should, in theory, provide similar enhancement
properties you can get with a good valve pre-amp. (Note here Eric. I said
"Similar" not the same.)

But. Clipping within the band and re-mixing it is certainly an interesting
concept.

I noted recently also that Vesta made an almost identical clone to the
Aphex type C box. The principal is probably well established now. I just
wish I could find an actual circus to the Aphex type from which I could
work. If anyone has such a circuit kicking round in their archive, I'll
swap you three chickens and a goat for it.

Thanks in advance.

Be absolutely Icebox.

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