Using The C20 Front Panel Tape Jacks; Using The C20 With Tape Decks; Using The C20 With Microphones For Stereo; Monophonic Record Settings - McIntosh C20 Owner's Manual

USING THE C20 FRONT PANEL TAPE INPUT JACKS
Two tape machines can be used with the C20
Stereophonic Preamplifier. After you have connected
your tape machine to the rear panel of the preamplifier
you may have someone bring in a portable machine to
make a copy of one of your tapes or to listen to one of
his tapes on your system. With the C20 you no longer
have to unplug your permanent machine. The C20 is
supplied with two cables. The cables have phone plugs
on one end to plug into the front panel of the C20 and
pin jacks on the other end to plug into any tape ma-
chine. (Adapters are available at any Hi-Fi retailer to
permit pin plugs to connect with phone jacks.)
To listen to the portable or second tape machine
plug the pin jack end of the two C20 cables, mentioned
above, into the tape machine output. Connect the tele-
phone plugs into the telephone jacks on the C20 front
panel. The left jack supplies the left channel. The right
jack supplies the right channel. Rotate the INPUT
SELECTOR switch to TAPE. When the tape jack switch
is depressed to the IN-PLAYBACK position, the perma-
nent tape machine output is disconnected from the
rear panel. The portable tape machine is now connected
and any program originating in this machine will be
heard through the C20, and will also be available from
the C20-TAPE OUTPUT to drive the permanent tape
machine input. This feature allows you to copy a tape
from the portable machine into your permanent ma-
chine, provided your permanent machine has its own
recording pre-amplifier.
To record on the portable machine plug the two
phono pin plugs of the two C20 cables into the input
of the portable machine. Leave the telephone plugs
connected to the C20 telephone jacks on the front
panel. Operate the tape jack switch to the OUT posi-
tion. The permanent tape machine will be reconnected.
Now any program picked up by the INPUT SELECTOR
switch will be available to drive the portable machine.
You can now make a copy on the portable machine
of any tape played on the permanent machine. You can
copy any other program source onto both tape machines
at the same time.
When recording from one tape machine to the
other the only controls that are effective are the HF
CUTOFF FILTER and the TAPE JACK switch. (Note: Some
portable tape machines will drive the C20 even though
the TAPE JACK switch is in the OUT position. This is
not a normal circuit use and a distorted signal usually
results. For low-distortion operation follow the rec-
ommended procedure.
Table 3. Recommended Settings of the RECORD COMPENSATOR Controls of the C20 for Monophonic Records
Manufacturer
Speed
Allegro
American
Recording
Society
Angel
12
RECORD COMPENSATOR
BASS TREBLE
(Roll-Off)
(Turnover)
33 LP
33 RIAA
33
RIAA

USING THE C20 WITH TAPE DECKS

The C20 Stereo Preamplifier may be used with
tape decks which do not have playback preamplifiers.
Tape heads require a form of playback compensation.
Setting the RECORD COMPENSATOR controls to the
TAPE positions provides correct playback for tape
heads and eliminates the need for using playback pre-
amplifiers with tape decks. (Note, however, that the
C20 cannot conveniently be used to record on tape. If
you need recording facilities in a tape machine, a re-
cording preamplifier will be required. In many tape
machines this preamplifier serves both playback and
record functions.)

USING THE C20 WITH MICROPHONES FOR STEREO

Microphones in stereo may be used with the C20.
If the microphones are low level (low output — 2 to
10MV) then they may be plugged into either an un-
used pair of low level PHONO 2-10MV jacks or an un-
used pair of low level TAPE HEAD 2-10MV jacks.
If the microphones are medium-level (10 to 70
MV), then they may be plugged into either an unused
pair of high-level PHONO 10-70 MV jacks or an unused
pair or high-level TAPE HEAD 10-70 MV jacks.
When reproducing from microphones in phono or
tape head channels set the BASS RECORD COMPENSA-
TOR control to 0 and the TREBLE RECORD COM-
PENSATOR control to TAPE. This adjustment gives a
flat response for the microphones.
If high-output microphones (100 MV and up) are
used, plug them into the auxiliary channel. In this
channel the RECORD COMPENSATOR controls do not
operate and it will be necessary to adjust the micro-
phones. All previous information given on microphones
applies.

MONOPHONIC RECORD SETTINGS

For several years record companies used many
different recording methods in an effort to give maxi-
mum entertainment value when
records.
If you wish to listen to monophonic records, switch
the INPUT SELECTOR to PHONO 1 M or PHONO 2 M.
Vertical output from the stereo cartridges is cancelled
by operating the INPUT SELECTOR to the M (mono-
phonic) positions. When listening to monophonic rec-
ords vertical output consists only of undesirable sounds
such as record scratch. The recommended settings are
as follows:
Manufacturer
LP
Atlantic
-12
Audiophile
Bach Guild
Banner
-12
listening to
RECORD COMPENSATOR
Speed
BASS
(Turnover) (Roll-Off)
33
RIAA
78
300
33
LP
their
TREBLE
LP
-10
LP