Table of Contents
Advertisement
Channel Balance
To check channel balance: Press the "Left"
button on the test panel and place the tone
arm on a left channel band. Use the "Zero
Adjust" control so the meter reads "0."
Switch to the "Right" button on the test panel,
and play a right channel band. The meter
should read "0," ideally. The variance (in dB)
should not be any greater than 2 on the meter,
which is the difference between left and right
channel outputs. This check may be com-
bined with the above crosstalk test to save
time and facilitate testing.
To measure actual voltage output of the cartridge,
Fig. 18
play a left channel band or a right channel band
of the TTR-109. Push the "Level" button on the
panel. The meter will read on a linear scale in
relation to the percentage of modulation (lower
scale).
Example: 100%
=
10 mV
50%
=
5 mV
35%
=
3.5 mV
VI. PHASE CHECK
Place TTR-103, Side 2 on the turntable; the TTR-
103 IS A 45 RPM RECORD. Press the "Low/MidM
~
m
m
~
button on the test panel and play Band 5. If you
observe a pattern as shown in Fig. 18, the chan-
Fig. 19
nels are out of phase. To correct this problem,
reverse the "hot" and ground leads on one chan-
nel at the pickup. Choose a channel which has
no ground tab. If this malfunction is found, the
customer should be advised to check the phasing
of his entire stereo system by means of a test
record such as the Shure "Audio Obstacle
Course." Fig. 19 is the pattern observed, using
Band 5, Side 2 of the TTR-103 when all equip-
ment is set correctly and operating normally.
VII. ANTISKATING FORCE AND TRACKING FORCE EX$LANATION
A. Antiskating Force Explanation
When the stylus contacts the record groove, a certain amount of friction is
present at the stylus tip. As the stylus tracking force increases, this friction
force also increases. This force pulls along a line running through the length
of the body of the pickup. The offset angle (which is used on most tone arms
to reduce the lateral tracking angle error) directs this force in such a rela-
tion to the pivot point of the tone arm, as to pull the tone arm in toward the
center of the record. This inward force, called skating force, unbalances
the forces on the groove wall. By adding an outward pulling force, called
antiskating force, to the tone arm, this force can be balanced. The stylus
is then able to exert equal force on both groove walls. Since the skating
force is proportional to the tracking force, any increase in the tracking force
will increase the skating force and will require greater antiskating to bal-
ance it. At this time, the antiskating force should still be set to the recom-
mended value of the manufacturer.
Advertisement
Table of Contents
