Hammond Organ L-100 Series, Service Manual

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Page 86
7–5 KON ZISSIS CHORUS DEPTH CONTROL
This modification improves the L100’s chorus tone and adds control over chorus depth.
A 500K linear taper potentiometer can work as a Chorus Depth Control by mixing the straight signal with the vibrato signal.
The 0.0047 μF capacitor wired across potentiometer pins 1 and 2 emphasizes the midrange and treble frequencies of the straight
signal above those same frequencies in the vibrato signal. This results in the rich, shimering chorus effect similar to that of a scanner
vibrato.
You can experiment with different capacitor values to alter the chorus effect. Suggested capacitors to try are: 560pF, 0.001μF,
0.0022μF, etc., through 0.01μF.
The figure below (
Figure 7–5 ) shows Kon’s modifications to the original circuit in red.
Figure 7–5: Kon Zissis Chorus Depth Control and Percussion Modification
7–6 KON ZISSIS PERCUSSION MOD
This modification improves the L100’s Percussion tone, volume, and attack. Refer to the blue changes in the figure above ( Figure 7–5 ).
Removed components are shown in parentheses.
Remove R128 (330kΩ) at the 12AU7 tube (V11) and replace it with a jumper so the percussion fast decay volume is the same as the
percussion slow decay.