[HAM] 60 vs. 64

[Kon Zissis]

Hi Denis. 
In my TG data spreadsheet  have the measured TG output curves of over
fifty Hammond organs including several that I have measured myself.
With looking at the output curves of the recapped pre 1964 organs and
the red mylar capped post 1964 organs I have noticed that there are drop
offs in the TG notes  73 to 84 range on several of these organs
including a 1973 B3 that I measured last week.
 I do not know if this drop off was  deliberately set up  as part of the
factory TG calibration  , however with my own experience with
recalibrating the TG I have  found that  the TG notes 73 to 91 are the
hardest to calibrate to an exact  desired millivolt output level because
when the set screw is tightened after I have set the pickup  to produce
the desired level  , the tightened screw causes the pickup magnet rod to
move slightly thus  causing the  output level  to either increase or
decrease and because of this  I have to untighten the screw again and
then  reposition the  pickup to  again produce  the desired output level
and then I retighten the set screw. If the pickup moves again then I
have to do this again until  the desired output level is produced after
the set screw has been tightened. 
 
This setting and then having to reset the pickup  because it moved after
the set screw was tightened is a real time consuming nuisance and I
assume that the  Hammond  employees who calibrated the TG would not have
been allowed to be this fussy because this would slow down the
production  so therefore my speculation as to what possibly might have
happened at the Hammond factory is  that the person  might have set the
pickup  to produce the  desired output level and then tightened the set
screw  and then not worried any more if the  pickup  moved slightly thus
changing the output level because the changed output level was
considered to be ''near enough''  so  therefore  it was left as it is
without  resetting it back to the correct output level. If this
speculation is correct then this might explain why so many organs have
uneven levels or drop offs in the TG notes 73 to 84 range.
 
With your 1964 B3 you can recalibrate the TG notes  73 to 84 to bring
them  up to  the levels that you want and you can  recalibrate the TG
note 85  to bring it down to a more appropriate level and this should
noticeably improve the organ sound .
All the best.
Kon
 
Denis  Wage wrote:
>On the other hand, my 1964 B3 #93380 has some problems.  First, tone 85
is really
>loud and very noticable.  Especially high C 8'.  I will be changing the
pickup on
>this tone.
>My question to the group is about tones 73 - 84.  You can plainly hear
the drop off
>of these tones in the upper half of the keyboard using 888888888.  It
is VERY
>noticeable.  Especially with tones 61-72 being slightly louder than
49-60.
>Any thoughts on this?