Introduction - McIntosh C33 Owner's Manual

Introduction

The Mclntosh C 33 is a super quality, high perfor-
mance Stereo Preamplifier. Its design has been
governed by insistence on great flexibility, versatili-
ty, low distortion and high performance with long
life.
The C 33 provides many features for your listening
enjoyment. They include:
1. a dual preamplifier system with separate listen
and record program lines, which allows listening
to one program source while recording from a dif-
ferent independent program source.
2. a low noise electronic input switching system,
which uses dual field effect transistors (FETs) and
short signal leads to give great source to source
isolation, low distortion, and freedom from noise
and hum pickup.
3. two, seven source, input selector switches for 3
tape decks, 2 turntables, 1 tuner, and 1 auxiliary,
which allow independent source selection for
listening and recording.
4. an electronic record monitor switch, which
allows the record program line to be heard
through the main listen output.
5. a five band program equalizer, which permits
the adjustment and improvement of the loudness
contrast of the five most important frequency
ranges. Each band can be emphasized or de-
emphasized to satisfy your listening taste. The
program equalizer can be switched to either the
listen or record program lines. This allows
equalizing the record output signal to tape
recorders or equalizing the main listening output.
6. a precision volume control, which is electroni-
cally trimmed during manufacture to maintain
channel to channel accuracy to better than 1
decibel (dB). This high order of accuracy assures
continuing program balance as the listening
volume is changed.
7. an active circuit loudness control, which is
electrically independent of the volume control.
Close conformity to the Fletcher-Munson equal
loudness curves can be attained regardless of the
volume control position.
8. high and low frequency filters, which reduce
high frequency noise and low frequency rumble at
a 12 dB per octave roll off rate.
9. a compandor, which permits expansion or com-
pression of the dynamic range of program mater-
ial from either the record tape output or the main
listen output. Compressed recordings and broad-
casts can be expanded on playback to restore
their dynamic range. Tapes can be recorded using
compression and replayed using expansion to in-
crease signal-to-noise ratio.
10. front panel tape recorder jacks, which allow
simple plug-in of an additional tape recorder
without disconnecting your regular system. This
makes tape copying to a portable recorder very
convenient.
11. a tape recording program line, which makes it
very easy to record phono, tuner, or auxiliary on
up to 3 recorders at the same time (4 recorders
when using the front panel tape recorder jacks) or
to copy from recorder to recorder. Recording
operations do not interfere with the separate
listen program line.
12. an automatic AC power control circuit, which
can conveniently turn off the entire stereo system
when the turntable turns off.
13. a built-in monitor amplifier, which provides 20
watts per channel power output and includes the
Mclntosh patented Power Guard protection cir-
cuit. The monitor amplifier can be operated from
the listen program line, the record program line, or
independently from a separate external source.
14. two front panel headphone jacks, which are
powered by the internal monitor amplifier.
15. two speaker output pushbuttons, which control
the operation of two sets of loudspeakers (when
used with the optional SCR-2 speaker control
relay) or two sets of power amplifiers.
16. electronically regulated power supplies, which
maintain stable operation even during periods of
low line voltage.
This outstanding preamplifier will serve you best
when you understand its functions and what it is de-
signed to do. Some time invested with this manual
will be valuable in your knowledge of how it works.
The simplified block diagram on page 3 shows how
the C 33's internal circuits are arranged. The simpli-
fied connecting diagram on page 6 shows how other
components are connected to the C 33.
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