Typical compression controls are provided, including threshold, ratio, attack, and release as well as unconventional controls for attaining the sound of numerous different types of buss compressors, such as four character switches for selecting between logarithmic or linear release curves, channel linking, program mode, and release smoothing as well as a variable saturation knob for warm, non-linear distortion, and a wet/dry mix on the final output that lets you engage in internal parallel compression effects. The 1978 features an internal linear, toroidal power supply with low hum and global compatibility, and includes an AC power cord, so you can get mixing and mastering right away.
Because the shaping controls have bell frequencies as well as shelf, they cover the full range of frequencies available within the 1978, and thus it is possible to control the mid frequencies using just the front-panel shaping controls without the need for an external insert. If you set the low frequency to 400 Hz bell and the high frequency to 3 kHz bell, you are effectively controlling the midrange with a wide bandwidth in just the same way as you would control the low and high frequencies. This could be used to adjust the overall balance of a mix, or on individual instruments, to bring out the raspiness in a voice, for example.
- Release Curve: in the out position, the classic logarithmic release curve is used, as on most compressors, but when pushed in, a linear release is used, resulting in a curve in which the initial release isn't as fast, for a less aggressive sound, especially on fast release times
- Channel Link: normally, left and right channels respond equally under compression. When engaged, the Wide channel linking changes to partial summing of the left and right channels before the sidechain, producing a wider image under compression
- PGM: this switch introduces a second, slower release time in proportion to the density of program material above the threshold, reducing excessive pumping under heavy compression
- Smooth: when pushed in, this adds extra circuitry to slow the initial release, which might otherwise introduce distortion at low frequencies (such as bass guitar) when using fast release times