Heathkit TA-16 - Operation; In Case of Difficulty

Page 30
OPERATION
Refer to Figure 1 for a description of the
various control functions.
CAUTION The loudspeakers used in this Guitar
Amplifier have been selected to handle ade-
quately all the power that the amplifier circuit
can produce. However, prolonged usage under
conditions of maximum power, full bass boost,
and overload distortion, may result in torn or
ruptured cones.
OPERATING PROCEDURE
1. Turn all the controls to their "0" position
and turn the LINE REVERSE switch to OFF.
2. Plug the line cord of the Amplifier into an
AC outlet.
3. Plug the instrument into the desired input
of the Amplifier.
4. Place the LINE REVERSE switch in the ON
position that gives the least amount of hum.
5. Now increase the VOLUME control (of the
channel being used) in small amounts while
alternately playing the instrument, until the
desired volume level is obtained.
6. Next, set the BASS and TREBLE controls
of this channel to obtain the tone desired.
7. If the Reverb channel is being used, you
should set the REVERB, TREMOLO RATE
and DEPTH controls as desired. NOTE: The
delayed reverb and tremolo circuits are
always in operation unless the foot switch
is plugged into the Amplifier and the
switches turned off, or the REVERB and
TREMOLO controls are set at zero.
ACOUSTIC FEEDBACK
Acoustic feedback occurs when vibrations (sound
waves) from the speakers are picked up by the
Guitar or microphone, or by the delay springs
in the reverberation unit. These vibrations are
converted into electrical signals and reamplified;
the result is a loud, continuous squeal or hum.
Acoustic feedback is more likely to occur when
using the Guitar Amplifier in rooms that are
small, with a low ceiling, and hard walls. Another
condition that causes acoustic feedback is plac-
ing the guitar or microphone directly in front of
or behind the speakers in the Guitar Amplifier.
Usually, acoustic feedback can be corrected by
using lower Volume and/or Reverb settings. At
high Reverb settings you may also encounter
mechanical feedback directly from the speak-
ers, through the cabinet, to the springs in the re-
verberation unit. If this occurs, use a lower
setting of the Reverb control.
There are two possible hookups that can be
used when two Heathkit Guitar Amplifiers are
available. See Page 41. One hookup willproduce
greater output power, and the other is for
special reverberation effects.
IN CASE OF DIFFICULTY
NOTE: Refer to the Kit Builders Guide for Serv-
ice and Warranty information. Refer to the X-Ray
View and the Chassis Photographs (fold-out from
Page 38) for the physical location of parts.
This section of the Manual is divided into the
following six sections: General Checks, Test-
ing Precautions, The Circuit Breakers, Trouble-
shooting Chart, Point-To-Point Hum Test, and
Signal Tracing. The General Checks describe
what you could do about the type of difficulty that
may occur right after the amplifier is as-
sembled. The next section describes some pre-
cautions to observe when making tests, and the
Circuit Breaker section tell you what to do if a
circuit breaker opens.
The Troubleshooting Chart lists some actual
difficulties that could occur, and tells what could
cause these difficulties. The Point-To-Point Hum