Crane Song STC-8 - Manual (Page 18)

PAGE 16
MODE SWITCH - KI SOUND AND OPTIONS
A number of vintage compressors have a frequency response that changes with gain change.
This is a result of changing circuit impedance and is typical of optical based compressors such
as the LA-2A and similar devices. These devices will be flat with no gain reduction and become
bright with gain reduction, or will loose hi end with no gain reduction and become flat with 6 to
12 db of gain reduction. It’s part of their sound and is highly prized by many people. How ever it
may not be what you want depending upon the application.
Part of the KI sound is similar to the above effect and part is a modification of the side chain.
There is a way to change the operation of the STC-8 so that only the side chain is changed in
the KI position of the mode switch. This means that the compression artifacts will become
second harmonic (normal mode of KI) but the audio path will be left transparent. This is done by
changing an internal jumper J3. The normal mode as shipped from the factory is with the effect
enabled.
The following drawing shows the jumper location. It is located close to the center of the main
cicuit board next to a yellow relay. With the jumper on the front 2 pins the HF effect will take
place. With the jumper on the back 2 pins the effect will not be engaged with the mode switch.
J3
If you do this the unit MUST BE FIRST BE DISCONNECTED FROM AC POWER, THE CORD
UNPLUGGED. You should ground your self to the unit before removing the top cover and
remain in physical contact with the unit to prevent static discharge. If you are unsure get a tech.
to change the jumper.
LIMITER SOURCE
J1 and J2 determine the signal source for the peak limiter. The normal mode of operation is on
the two left most pins. This is set so the limiter is referenced to the output, post gain control. It is
recommended that the jumpers be left in this position. Please contact us before changing J1
and J2.