[sdiy] 60s organ sound

[Peter Forrest]

My first organ (bought in 1970 in preference to a Vox Jaguar!) was a Bird,
which used neons.  Very temperamental, but a very sweet tone indeed.  The
GEC KT66 tube amp probably helped as well.
And yes, I still have it somewhere..... not functioning.
Peter


----- Original Message ----- 
From: "Ken Stone" <sasami at hotkey.net.au>
To: "Antti Pitkämäki" <anpitkam at hotmail.com>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, December 14, 2004 8:15 PM
Subject: RE: [sdiy] 60s organ sound


> In the case of a neon divider, the dividers are actually relaxation
> oscillators running at over 1/2 the speed of the octave higher. As such
they
> have a sawtooth wave shape. To get the frequency correct, they are
> hard-synced to the octave higher. As the neons near their strikec voltage,
> the pulse from the octave above is enough to trigger them. When they are
> only part way through their cycle, the trigger pulse is insufficient to
> cause striking, as such they cycle at 1/2 the rate of the octave above.
>
> Ken
>
> >BTW, somebody claimed that dividers can only produce square waves,
because
> >it is "the only binaric (?) waveform", but somebody else claimed that it
is
> >possible to make pulse wave dividers and they can be made from the same
> >amount of parts as square wave dividers... Does anybody have any
information
> >on this? I suppose square waves can be converted to other waveforms, but
is
> >this the only way to get pulse and sawtooth waveforms from a
divider-based
> >instrument? At least I think that the tube Philicorda organ might make
> >sawtooth waves directly from its dividers. There's some information on
this
> >site about this, but it's in German:
> >http://home.t-online.de/home/pam.nickel/bb/7500.htm
> >
> >Antti Pitkämäki
> >
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> _______________________________________________________________________
> Ken Stone   sasami at hotkey.net.au or sasami at cgs.synth.net
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
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>
>
>