Vibrato
Line Box Capacitor & Resistor
Replacement Kit

Custom Kits are
available for all models of Tonewheel Generator
Organs

What is
HAMMOND Vibrato?

The HAMMOND Vibrato is
an effect created by the periodic raising and
lowering of pitch. It is fundamentally different
from a tremolo effect or changes in loudness.
HAMMOND originally compared the Vibrato effect in
a HAMMOND organ to the effect produced when a
violinist moves a finger back and forth on a
string, varying the frequency while maintaining
constant volume.

Special Vibrato
equipment in most Tonewheel generator equipped
models of HAMMOND organs was designed to vary the
frequency of the tones by continuously and
consistently shifting their phase through the use
of an electrical time-delay line or
“phase-shift network”. This network was
composed of a number of low-pass filter sections
and a motor-driven Vibrato Scanner, which was
coupled to the end of the Tonewheel Generator
shaft adjacent to the organ’s Run Motor. The
degree of Vibrato being scanned was variable
through the use of a rotary switch with
three-degrees of Vibrato. V3 scanned the entire
Vibrato time-delay line to be scanned for a
“wide” Vibrato effect. V2 scanned about
one-half of the Vibrato line for a
“narrower” Vibrato effect. V1 scanned
about one-third of the Vibrato delay line, and
produced an even “narrower” Vibrato
effect, but still was very noticeable when
compared to the normal non-Vibrato sound of the
organ.

What is
Vibrato Chorus?

In many later HAMMOND organ models (B-3,
C-3, A-100, etc.), a Vibrato Chorus or
“shimmer” effect was added to the
Vibrato system. The Vibrato Chorus was an effect
similar to the result of mixing two or three
slightly out-of-tune frequencies together. It is
produced in the organ by mixing the Vibrato
output signal with a portion of the signal
without Vibrato. As the Vibrato effect is applied
to the part of the signal across the delay line,
but not to the rest of the signal, which is
applied to a resistor across the line, the
combination produces the famous HAMMOND Chorus
effect. This effect is similarly variable (on
organ equipped with Chorus) through the rotary
switch positions C1, C2 and C3.

By far, the most common Chorus setting used
by professional organists is position C3,
especially when used with a Leslie speaker on
Chorale (slow). Many of the considered
“best” performances of professional
HAMMOND organists have utilized Chorus in
conjunction with Reverb and Percussion.

What is the
Vibrato Line Box?

The Vibrato Line Box houses the delay-line
Filter Capacitors, Resistors and Inductors which
work as a group to provide clean, consistent
Vibrato and Chorus. In the most common models of
Tonewheel Generator organs, the Vibrato Line Box
was usually configured in one of three ways
depending upon specific organ model and date of
manufacture. Many early HAMMOND organ
(manufactured prior to the mid-1950’s) Vibrato
Line Boxes were housed in Black-painted or
Silver-painted wooden boxes, attached to the
underside of the top of the organ as viewed from
the rear.

The latest “open-frame” style
Vibrato Line Box, featuring a greatly simplified
design, was introduced in the mid-1950’s. In the
open-frame style Line Box, the capacitors can be
clearly seen housed in a metal frame. The newer
Line Box design contained many less delay-line
components. The later style open-frame Vibrato
Line Boxes were attached to the rear of the upper
manual in console organs, or in various other
places on other models of organs. Due to the age
of all HAMMOND Tonewheel Generator organs, the
Vibrato Line Box components should be replaced
with a hand-matched set of critical value Filter
Capacitors and Resistors.

Why does a
Vibrato Line Box need to be rebuilt?

All Vibrato Line Boxes contain critical
value Filter Capacitors and Resistors in addition
to fixed inductor coils. The Filter Capacitors
and Resistors age randomly in a similar manner to
the original Tonewheel Generator Filter
Capacitors, causing inconsistent performance in
the Vibrato and Chorus. The key to the classic
Vibrato and Chorus effect is the consistency of
the Capacitors, Resistors and Fixed Inductors
throughout the many sections of the Vibrato Delay
Line. Once the individual components become
unstable, the original sound is lost.

Due to the differences in the various
Vibrato Line Box styles, the component types
vary, and are NOT interchangeable among the
Black-painted, Silver-painted and Open-Frame
style Line Boxes.

NOTE:
Since many organs require different installation
techniques, we recommend that a Qualified HAMMOND
Organ Service Technician be contacted for
installation help if the owner of the organ has
no previous experience in electronics,
particularly soldering and component removal /
installation techniques. Many HAMMOND owners have
also successfully installed our new Kits
themselves with excellent success!

A technical description of our
Tonewheel Generator Filter Capacitor Replacement
Kit can be found in our ON LINE Catalog. We
recommend that the Vibrato Line Box Kit be
installed with the Tonewheel Generator Filter
Capacitor Replacement Kit for best results.

Please
supply your Organ Model and Serial Numbers when
ordering our Vibrato Line Box Capacitor &
Resistor Replacement Kit.

GOFF Professional
offers Mail-Order repair and rebuilding services
for your Tonewheel Generator and Vibrato Line
Box, in addition to complete Leslie tube
amplifier and HAMMOND tube preamp rebuilding. We
can restore them back to factory-fresh operation
and help you refurbish your own organ by handling
the difficult rebuilding tasks in our CT shop.

We can repair, restore, rebuild and/or
modify your existing Hammond organ and Leslie and
upgrade single-speed Leslie models to two-speed
operation! Custom Cabinet Refinishing / Repair /
Painting available.

Roll-or-Kari Organ Moving
Dollies and flat Leslie Moving Dollies are also
available. Please review our ON LINE Catalog for
details.

Email
GOFF Professional for parts,
equipment, information or technical assistance
with any Hammond Organ or Leslie Speaker
[email protected]

REV. 11-27-97
APG / BPG