Hammond Model A, Руководство пользователя, Страница: 41 / 298

When the vibrato chorus switch (Fig. 7) (Models AV, BV, BCV, CV, DV, and RT) is
pushed to the left, normal vibrato is obtained with the vibrato switch in positions
1,2, or 3. When the lever is pushed to the right a chorus or ensemble effect,
combining foundation organ tone with vibrato tone, is obtained. The center position
of this switch is not intended to be used. No harm will result from leaving the
switch in this position, but reduced volume will be obtained.
Models B-2, B-3, C-2(G), C-3, RT-2, RT-3, A-100 & D-100 have the selective vibrato
feature which makes the vibrato effect available on either manual separately
or on both together. Two tilting tablets (Figure 3) control the vibrato for the
two manuals, while the rotary switch selects the degrees of vibrato or vibrato
chorus effect. The Great tablet controls the vibrato for the pedals as well as
for the Great manual.
The vibrato is not present on models having the tremulant.
PERCUSSION
The Percussion feature (Models
B-3, C-3, RT-3, A-100, and D-100) is controlled
by four tilting tablets (Fig. 8) 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 after the
vibrato but before the expression control. The control tubes are keyed through the
eighth harmonic key contacts and busbar.
TONE GENERATOR
The main tone generator furnishes 82 or 91 different musical frequencies.
depending on the console model. It includes a tone wheel, magnet, and coil
for each frequency. Mounted on top of the generator are tuned filters to
insure purity of the tones.
FIGURE 8
8