Moog Music Slim Phatty - Manual (Page 13)

Page 14
Slim Phatty User’s Manual - The Components
Page 15
Slim Phatty User’s Manual - The Components
Finally, the Overload (O.L.) parameter allows you to set the amount of signal clipping from none to soft to
hard clipping as the amount is increased. The results you get with Overload will depend on the settings of
the oscillator waves and levels, and the filter cutoff and the filter resonance settings in addition to Overload
amount. Note that Overload is not the same distortion you’d get from a fuzz box. It can be quite subtly ap-
plied to add just a touch of ‘bite’, or aggressively applied to add a jagged edginess to the sound.
Filter Section controls:
Cutoff:
When the CUTOFF switch is selected, the analog edit control is used to adjust the filter cutoff frequency.
The cutoff frequency is adjustable from about 20 Hz to 16 Khz.
As the edit control is rotated clockwise, the
cutoff frequency is increased, allowing more of the signal harmonics to pass through the filter.
Resonance (RES):
When the RES switch is selected, the analog edit control is used to adjust the filter resonance. Resonance
causes feedback in the filter circuit, adding harmonic emphasis at the cutoff frequency. When the Resonance
control is all the way down, the lowpass filter acts basically as a tone control, rolling off the high end of the
signal as the Cutoff control is turned down. As Resonance is increased, the filter begins to form a peak at
the cutoff frequency. This emphasizes harmonics near the cutoff frequency, and can result in a ‘wah-wah’ ef-
fect when resonance is set fairly high and the filter cutoff is varied. As the resonance is turned up the peak
increases in strength until it begins to self-oscillate – creating a sine wave with the same frequency as the
cutoff frequency.
Keyboard Control Amount (KB):
When the KB switch is selected, the analog edit control is used to adjust the amount of post-glide keyboard
voltage that is routed to the filter cutoff frequency. When the edit control is rotated fully clockwise, the filter
cutoff follows the key played on the keyboard. A higher key will cause a higher cutoff frequency. This allows
a sound to retain its brightness as it is played higher on the keyboard.
Envelope Generator Amount (EG):
When the EG switch is selected, the analog edit control adjusts the amount of the Filter Envelope Genera-
tor output that affects the filter cutoff. The Envelope Generator Amount is bi-polar, as indicated by the
legend on the panel, so the amount is 0 when the edit control dial is at the 12 o’clock position. Rotating the
control CW from that point adds a positive EG amount to the filter cutoff, while rotating the control CCW
from that point adds a negative amount to the filter cutoff.
Overload (O.L):
When the O.L. switch is selected, the analog edit control adjusts the amount of pre-filter and post-filter clip-
ping. Overload can be used to warm up sounds and give them a distinctive tonal edge. Advancing the edit
control increases the amount of clipping from the subtle warmth of soft clipping to the ‘growl’ provided by
the beginnings of hard clipping. When set to 100%, Overload adds a volume boost of about +6dB.
Additional CV control:
The FILTER jack on the back panel is a CV input for external control of the filter cutoff parameter. The jack
accepts -5 to +5 volts, or an expression pedal like the EP-2. A voltage applied to this jack is added to the
setting of the filter cutoff control. A one-volt change in the control voltage will change the cutoff frequency
of the filter by about one octave.