SINE RATE
Controls the rate of the sine wave LFOs. A sine wave is similar to the triangle wave but the
rises and falls in output voltage are more gentle. The waveform is more akin to natural
resonances slowing down before it changes direction.
SINE DEPTH
Controls the depth of the sine wave modulation. Sine waves produce a more natural sounding
pitch change when they modulate a BBD.
BALANCE
This adjusts the mix between the unaffected signal and the one coming from the delay line or
lines. DRY is the unaffected signal while WET is the delayed signal.
MODE SWITCH
This sits between the two right most pots and is key to understanding what the modulation
section of the SE330 does. It has three positions; dimension, stereo and quad.
There are four bucket brigade delay lines in the SE330. Each side of the stereo signal has two
dedicated BBDs and each BBD has its own driver circuitry which controls the delay imparted
by the BBD. These driver circuits are modulated with low frequency oscillators. Thus each
LFO can alter the delay time exhibited by the BBD it controls.
There are four LFOs in the SE330 but they are not connected so that one LFO controls its
own BBD. This should work well but in practice it doesn't give the sound of the classic
Japanese string machines and effects units that we want to hear. So the SE330 does something
much more complicated and, in doing so, can mimic most of the well known ensembles units
of the past.
Dimension Mode
This is the simplest of the SE330's three modes. Only two BBD lines are used in this mode,
one for the left hand channel and one for the right. The mono input is shared equally to each
BBD's input. Each BBD produces a similar delay when not modulated so that the sound from
both left and right is more or less the same. Two LFOs, one whose output is a triangle wave,
the other, whose output is a sine wave, are used as modulation sources. The rate and depth of
each LFO is controllable from the front panel controls. Both BBDs are modulated by the sum
of both LFOs. That is, both LFOs control both BBDs together. However, there is one
important difference between the modulating signals that are sent to each BBD. The BBD that
affects the right hand side operates inversely to the left hand one. So that when the delay of
the left hand BBD is increasing, the right hand one is decreasing.
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