[sdiy] Note volume compression in the Hammond organ

[Adam Inglis (sdiy)]

> On 3 Jul 2020, at 11:09 am, Ben Bradley <ben.pi.bradley at gmail.com> wrote:
> 
> As a teen in the 1970s I DID notice this in my Farfisa MiniCompact,
> and I knew enough electronics to see what was doing it. Each generator
> output went to the keyswitch board that had a 47k resistor between the
> generator output and the switch. The summing resistors for each of the
> three busses were also (IIRC) 47k, so each key's signal really dropped
> as more keys were played. I replaced the summing resistor with a 4.7k
> which of course reduced the signal a lot, but the keyboard sure
> sounded and felt different, more dynamic as each note held its volume
> as more keys were played. The original was like a compression effect.


Ha! My beloved late-60’s Farfisa Compact exhibits this ‘effect’ - it is definitely an important part of it’s sound.

A
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