McIntosh MA 230 - SERVICS BULLETINS, Owner'S Manual

Page: 10 / 24

LF (Low Frequency Filter)
LOUDNESS
Use the LF filter to reduce low frequency
noises created by a turntable, record changer,
or vibration acoustically coupled to the phono
player from the speakers.
FLAT.. .filter disconnected; flat response.
FILTER . . . low frequencies reduced
sharply below 50 cycles.
When you turn down the volume, music
seems to lose much of its bass and some of
its treble. This effect is due to the sensitivity
characteristics of human hearing. The re-
sponse of the human ear to bass and treble
pitch decreases more rapidly than its re-
sponse to the mid-tonal range. The LOUD-
NESS switch automatically provides the cor-
rect amount of bass and treble boost re-
quired to compensate for this change in
response of the human ear at low loudness
levels. Use the LOUDNESS switch in the
COMPENSATED position to listen at low
volume and still hear full frequency range.
HEADPHONE
S P E A K E R
ON
POWER
ON
HEAD PHONE HEAD PHONE
OFF OFF
Use the HF filter to minimize surface noise
when reproducing old or badly worn record-
ings.
FLAT... filter disconnected; flat response.
FILTER . . . high frequencies reduced
sharply above 5000 cycles.
Two pairs of low impedance stereo head-
phones can be connected to the MA230.
Both front panel headphone jacks are con-
nected to the MA230 output through 100
ohm resistors. These resistors provide the
correct output volume level for headphone
operation.
8
HF (High Frequency Filter)