[sdiy] Top Octave Generators, beehiving and leakage

[Roy J. Tellason]

On Friday 02 May 2008 14:25, dragon.servicing wrote:
> Hi,
> I think that the background noise on the older organs is called
> Beehiving. some models have worse background noises than others. It
> seems it is quite hard to design an organ that has a low background
> noise. Dc switching ( electronic switching ) on the keyboards ( rather
> than switching the audio directly ) can help as you can then keep the
> audio signals away from other bits of wiring and circuitry.
> I think the leakage knob may be to simulate the effect of all the
> different tonewheels being together on a Hammond organ.
> ( the signal levels from the tonewheel generators are quite small, so
> there may be coupling ? effects between them) .
> regards Peter

Some of the worst offenders in that regard were Hammond organs all right,  but 
not the tonewheel generated ones,  but rather the later all-solid-state 
units.  The name "Concorde" comes to mind for one example.  I think that 
ground connections and such got worse over time,  too.  There were times when 
I ran multiple service calls for the same customer over a period of years,  
and saw this sort of thing getting worse.  Darn near impossible to track 
down,  too...

> Dave Manley wrote:
> > Roy J. Tellason wrote:
> >> I'm thinking of all that background noise I used to hear in some of
> >> those organs I worked on....
> >>
> >> It's not at the outputs,  but all that stuff going on being picked up
> >> elsewhere,  particularly in any lower-level circuitry that's the
> >> problem.
> >
> > In pursuit of emulation perfection, The VOCE tone-wheel modules give you
> > a 'Leakage' knob to set the level of all this buzzing crosstalk.
> >
> > http://www.voceinc.com/
> >
> > -Dave
>
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