Gates SA-39 threshold mod, is it really needed? What does it do?

[Kilohertz]

About to complete the mods on my SA-39 and I am reluctant to drill a hole in the front panel to add "threshold" adjustment. I am just wondering why is the threshold adjustment needed? Doesn't changing the input level accomplish the same thing? It is just changing the level at which compression begins, unless I don't completely understand the side chain operation.

In the manual the circuit description describes the threshold point  "This has been arbitrarily set in design for convenient operation",  which to me means it doesn't really matter where it's set. ??

Somebody please help me decide if this is really needed. If it does offer a definite benefit, I'll drill the hole for it and add the control.

Thanks

 

[emrr]

If you look at DaveP's charts, you will see that it's really ratio; the two are interlocked.  I've never put ratio into an SA-39.