Specifications

PRODUCT
ANALYSIS
THE McINTOSH C 27
STEREO PREAMPLIFIER
Fig.1 - Front view
MANUFACTURER'S PUBLISHED
LIMITS (SPECIFICATIONS):
PERFORMANCE
Rated Outputs: Main, 2.5 volts (Maximum greater
than 10 volts) into 22k ohm load or greater; Tape,
0.25 volts (Maximum greater than 1 0 voltsl into 22k
ohm load or greater; Center Channel (L+ R), 2.5 volts
into 22k ohm load or greater. Input Sensitivities: High
Level, 250 millivolts at 1 00k ohms; Low Level (Phono
1 & 2), 2 millivolts at 47k ohms and 1 00 pF. Frequen-
cy Response: (any input): 20 Hz to 20 kHz, +0, -0.5
dB. Hum and Noise: (Phono): 80 dB below 1 0 mV in-
put, unweighted, 85 dB IHF "A" weighted; (High
Level): 85 dB unweighted; 90 dB IHF "A" weighted.
GENERAL SPECIFICATIONS:
Dimensions: Front Panel: 16" W x 5-7/16" H.
Chassis: 1 5" W x 5" H x 1 3" D including PANLOC
shelf and back panel connectors. Required knob clear-
ance in front of mounting panel: 1 1/2". Net Weight:
20 Ibs. Power Requirements: 1 20 V, 50/60 Hz.
Serious devotees of the audio art may be somewhat
surprised to find that Mclntosh Laboratory Inc. has
introduced yet another top performing
preamplifier/control unit, less than one year after the in-
troduction of their all-out C 32 preamplifier. In previous
times, Mclntosh was never noted as a company that
subscribed to the annual cosmetic "model changes"
so often seen from other high fidelity component
manufacturers. Well, for all those thousands of
dedicated Mac fans let us preface this report by stating
emphatically that the newly designed C 27 is much
more than a cosmetic face-lift of older models. In fact,
the highly acclaimed "Mclntosh look" of the front
panel has been retained, while new internal circuitry,
from stem to stern, makes this new entry a state-of-
the-art design that should enjoy the same sort of lon-
gevity typical of other Mclntosh products. The earlier-
introduced C 32 was, as we said, a multiple featured
product, with such built-in accessory features as a full
five-control graphic equalizer and an adjustable linear
expander, not to mention its fully separate monitor-
ing/headphone amplifier output facilities.
The C 27 takes a more restrained approach in which
those features that are deemed important to most pre-
amplifier/control users are retained but other accessory
facilities are omitted in favor of a suggested retail price
that will be affordable to a greater number of potential
purchasers. Think of the C 27 as a "middle of the
road" unit in terms of its control facilities and flexibility.
It is not a unit that subscribes to the "straight wire with
gain" approach - an approach which we, at least,
have always felt is a bit unrealistic. After all, how many
of us are blessed with companion components,
speakers, or even room acoustics that require absolute-
ly no control "tweaking"? Rather than do away with
such control features as tone controls or filters, it
seems to us that it is far more useful for the consumer
to have these facilities providing that their presence in
the signal path does not introduce any form of distor-
tion. Evidently Mclntosh felt the same way and, as we
learned during our lab testing of the C 27, these fea-
tures, when deactivated or, in the case of the tone con-
trols, when placed in their nominal flat positions, do not
in any way negate the "straight wire with gain" con-
cept which some purists espouse.
The front panel of the C 27, pictured in Fig. 1, is
anodized gold and black with Mclntosh's familiar gold-
teal panel nomenclature illumination which magically
appears when power is applied. Rotary controls along
the top of the panel include a five-position program in-
put selector (aux 1, aux 2, tuner, phono 1 and phono
2), a mode selector (left or right to both outputs, stereo
reverse, stereo, L + R mono, left plus right to left or
right outputs) and, at the extreme right, the master vol-
ume control. The four rotary control sets at the lower
right of the panel are dual concentric types. The first of
these introduces, singly or in combination, the high and
low cut filters and selects either or both sets of loud-
speakers which can be switched via the front panel
providing that the power amplifier's outputs are con-
nected to the rear of the C 27 instead of directly to the
speakers. Bass and treble tone controls permit tonal
tailoring of each channel separately while the right-
most control in this group is a combination balance and
loudness control. The loudness control of the C 27
Printed With The Permission Of Electronics Laboratories
17
Electronic Laboratories'