VOCE V3, H VIBRATO SCANNE

[dave.amels@sfnet.com]

Brian Nelson wrote:

H >He mentioned re: the Voce V3 that the sound is "generator" derived
H >and features a *detuning* feature with regards to the temperment of
H >the instrument.  Dave, could you explain the tuning/temperment
H >properties of the Hammond.  Is this tuning/temperment situation
H >a byproduct of tonewheel generation, or are the wheels just pitched
H >differently? Is the original pitch scale just slightly "just"?

The frequencies produced by the black drawbars of the B-3 are slightly out 
of tune.  This is because they are derived from the musical scale which 
does not have an exact integer multiple relationship between tones other 
than octaves.  Generators are shared in the B-3 for economy sake.  Lets 
look at an example:

Let's say you are playing a "A2" note with only the 16' and 2-2/3' drawbar 
pulled out.  The "A2" 16' tone is produced by tone wheel #22 creating a 
frequency of 110.0 Hz and the 2-2/3' drawbar tone is produced by tone 
wheel #53 producing a frequency of 659.2551 Hz.  This is the same wheel 
producing the 16' tone for the "E5" note.  The frequency for a true 2-2/3' 
pipe stop would be 660.0 Hz for the "A2" note, exactly 6 times the 16' 
frequency.  Of course if Hammond had wanted to produce tones exactly the 
way a multi-ranked pipe organ did they'd need 549 tones wheels instead of 
just 91.

H >Also...I'm having vibrato scanner problems myself.  My local tech
H >agrees that oil has leaked into the unit.  But...he said that it can
H >be cleaned with naptha (among other things) and it should be good
H >for a couple of years.  Repair or replace?

I believe a reconditioned one runs about $200.  It's also quite a job to 
remove one from you organ.

/Dave


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