ALM ALM003 - Manual (Page 7)

Overview
The SID GUTS panel provides both direct user and interfaced voltage control of the
various SID chip audio parameters.
The SID GUT’s can be best thought of as a core wave table based oscillator with a
built in multi mode filter and a second cross modulation oscillator. This provides
classic SID type sounds but with modular levels of control.
Synthesized audio is output through the 'output' jack. The external input allows
external audio to be passed through the filter. Note this feature is not available with a
SwinSID chip.
Oscillator control
The frequency of the core oscillator is controlled by the 1 volt per octave input the
the lower left hand corner of the panel. It responds to 0-5v giving a range of 5 octaves.
The oscillator base frequency can be offset (i.e tuned) giving a further total range of
8 octaves. This is achieved by pressing and holding both the Filter and Mod Osc
buttons at the same time and then releasing. All Filter and Mod Osc LEDs will light
indicating tuning mode is active. By then repeatedly pressing and holding either the
Filter or Mod Osc buttons, the oscillator can be tuned. Hold both buttons again to exit
tuning mode.
The core oscillator can also be turned off by holding the Waveform and Mod Osc
buttons simultaneously. All wave shape LEDs will turn off indicating that the oscillator
is de-activated. The oscillator can be turned back on by pressing just the wave shape
button. This feature can be useful when using an external audio signal (though the
signal can still be apparent at very low volume on some SID chips)
ALM-003 - ‘SID GUTS’
7