VIBRATO
The vibrato effect is created by a periodic
raising and lowering of pitch, and thus is
fundamentally different from a tremolo, or
loudness variation. It is comparable to the
effect produced when a violinist moves his
finger back and forth on a string while
playing, varying the frequency while
maintaining constant volume.
The vibrato mechanism includes an electrical
time delay line, which shifts the phase of all
tones fed into it. A rotating scanner, mounted
on the main tone generator, picks up
successive signals from various line sections.
These signals represent various amounts of
phase shift, and the combination of signals
produces a continuous frequency variation.
Figure 5
These Models have the "selective vibrato" feature which makes the vibrato effect available on
either manual separately or on both together. Two tilting tablets control the vibrato for the two
manuals, while the rotary switch (Figure 5) selects the degree of vibrato or vibrato chorus effect.
The "Great" tablet controls the vibrato for the pedals as well as for the Great manual.
PERCUSSION
The "Touch-Response Percussion" feature is controlled by four tilting tablets (Fig. 6) at the upper
right side of the manuals. Percussion is available only on the upper manual and only when the 'B'
preset key is depressed. The four tablets (from left to right) select Percussion on or off, normal or
soft Volume, fast or slow Decay, and second or third Harmonic tone quality.
Percussion tones are produced by borrowing the second or third harmonic signal from the
corresponding manual drawbar, amplifying it, returning part of the signal to the same drawbar, and
conducting the balance of the signal through push-pull control tubes where its decay
characteristics are controlled.
The Percussion signal is then combined with the
signal from the manuals and pedals after the vibrato
circuit but ahead of the expression control. The
control tubes are keyed by the eighth harmonic key
contacts and busbar.
4
tuttotastiere.com
