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Percussion

Percussion in L100 doesn’t sound remotely like the one in other Hammonds. It decays very slowly even on Fast setting. Despite the fact that I really like the Slow setting, Fast decay in L100 is absolutely unacceptable. To change it, you need to replace a few resistors and capacitors.

L100 has different circuit for percussion. Because the decay is quite long, the only noticeable difference between Fast and Slow setting will be percussion length. In other spinets/consoles percussion decays so fast that human ear perceives it as quieter. Therefore the circuit is designed in the way that when long decay is set, percussion is made softer to preserve the same effective loudness.

It does not happen in L100 and can become quite annoying after the modification. The situation could be remedied however and you will get nice sharp and short percussion.

To modify the percussion, open preamp/percussion amp box and:

1. to shorten the percussion length:

    - change C210 to smaller value (e.g 68nF)

    - replace R409 (try values between 470k and 1M)

2. to improve treble response (sharp percussion with more keyclick):

    - remove C208

You should now have a nice sharp and fast decaying percussion similar to B3/C3. You can use R409 470k and 470k potentiometer in series to adjust percussion length to your taste.

However doing this you will sometimes have very quiet percussion (when turning the potentiometer all the way down). The ‘effective loudness’ of fast decaying percussion will be significantly lower.

I recommend using a DPDT switch instead of the potentiometer. And with ON-OFF-ON type of switch you can have 3 different lengths for Fast setting.

This is what I have done:

 

In OFF position the signal travels through both resistors - longest decay

In ON(B) position the signal goes through 470k only - medium decay

In ON(A) position the signal bypasses both resistors - shortest decay

Also in this position R222, R223 and C213 (in percussion amp) are bypassed boosting percussion signal a little. The difference in ‘effective loudness’ for all 3 settings is unnoticeable.

Setting ON(A) is my favourite setting. Very B3-like.