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Introduction
Congratulations on your purchase of this API 500 format compatible
SSL VHD+™ Pre Module.
This module has been specifically designed to operate in a 500 for-
mat rack such as the API lunchbox® or equivalent. In common with
many such modules, the nominal input/output level is +4 dBu.
The VHD+ Pre is an immensely versatile recording and processing
device. It can deliver ultra clean SSL SuperAnalogue™ grade re-
cordings but also features a switchable VHD mode. SSL’s patented
Variable Harmonic Drive (VHD) system uses a 100% analogue sig-
nal path to generate rich harmonic distortion. As you increase VHD
input gain, the Variable Harmonic Drive process introduces either
2nd or 3rd harmonic distortion or a blend of the two to your source
material. At lower gain settings it adds gentle valve-style warmth
or a touch of transistor edge. As the gain is increased the more
extreme the distortion becomes until at high gain settings it delivers
fierce trashy transistoresque grunge.
Operation
Please refer to the illustration opposite.
Signal LED
The signal LED is a tri-colour LED that indicates level according to
the following table.
LED colour
+24dB Scale*
+18dB Scale*
Green
-24dBu
-24dBu
Yellow
+4dBu
0dBu
Red
+21 dBu
+16dBu
* The LED scale is selected from a jumper on the module PCB.
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