Owner`s manual

CHAPTER 4 -
35
CHAPTER 4 -
Modular Components of the TimewARP 2600
4.3.3
VCO 3
VCO 3
generates sawtooth, pulse, and sine outputs; the pulse width is manually
variable. The sine output is a TimewARP 2600 extension; the original ARP 2600 VCO3
provided just sawtooth and pulse outputs.
The default signal to the  rst (unattenuated)
FM Control
input is from the keyboard.
FM Control input is from the keyboard. FM Control
The
Audio/LF
switch above this input switches the mode of the
Audio/LF switch above this input switches the mode of the Audio/LF
VCO
from
Audio
(10Hz
- 20,000Hz)
to LFO Mode
(0.03Hz – 30Hz). When the
VCO
is in
LFO Mode,
the default
connection to the keyboard is removed. This can be overridden in this mode by
patching a cable to the
Keyboard CV
output on the left side of the front panel.
Keyboard CV output on the left side of the front panel.Keyboard CV
The default signals to the next three
FM Control
inputs are from a) the
Noise Generator,
b) the
ADSR Envelope Generator,
and c)
VCO2
sine.
4.4
Voltage Controlled Filter (VCF)
The
Voltage Controlled Filter
has variable cutoff frequency (Fc) and
Voltage Controlled Filter has variable cutoff frequency (Fc) and Voltage Controlled Filter
resonance (Q). The response below Fc is  at down to DC; above Fc the
response falls off at 24Db per octave. Fc range is from 10Hz to 10KHz
without control voltages; under voltage control, Fc can be driven as far
down as 1 Hz and as high as 20KHz.
Fc is controlled manually by a coarse tuning slider (labeled initial  lter
frequency) and a  ne tune slider. Fc may also be controlled by external
voltages; the sensitivity under voltage control is 1.0vV/oct.
The Q, or resonance, of the  lter circuit is controlled by a single
manual slider. As the Q is increased by moving this slider from left to
right, the response below Fc is gradually attenuated until a sharp peak
remains at the cutoff frequency. (Gain at Fc is always unity.)
At this Q setting, just below the point at which oscillation begins,
the  lter will ring distinctly in response to any sharply de ned pulse
presented to its signal input. In this state it is effectively analogous to
a highly resonant physical system, and may be used for various percussion effects
depending on its resonant frequency (identical to Fc) and on the impulse spectrum
exciting it.
As the Q is raised still higher, beyond about the halfway point in the slider travel, the
 lter will oscillate. Operating in this state, it generates a pure sine wave. even in the
absence of any signal input.
The
VCF
has  ve
VCF has  ve VCF
Audio
signal inputs. They are fed through logarithmic attenuators to a
summing point, and then to the
VCF
itself. The default input signals are from the
VCF itself. The default input signals are from the VCF
Ring
Modulator, VCO-1 Square, VCO-2 Pulse, VCO-3 Sawtooth,
and
Noise Generator.
The
VCF
has three frequency
Control
inputs. The  rst is normally from the
Keyboard
pitch-
control. The slider that governs this input is a TimewARP 2600 extension; on the original