McIntosh Stereotech 4 Service Manual

Page 2

SPECIFICATIONS

CABINET SIZE SHIPPING WEIGHT
28 high l6-l/2H wide l3-5/l6 deep 66 lbs
CONSTRUCTION SYSTEM WEIGHT .
#5 pound density non-resonant particle board panels. 56 lbs
Extra heavy I inch front panel. Heavy guage 8 mil
vinyl. Simulated walnut finish. CROSSOVER FREQUENCIES
SPEAKER SIZE 600HZ 5 SSOOHZ
Woofer l2 dia. frame size (9-l/2 dia. radiator) IMPEDANCE
Mid-range 5 dia. frame size (3-l/8H dia. radiator)
Tweeter 1-5/8 dia. radiator 8n Nominal
CONTROLS

Mid-range 600Hz To SOOOHz - boost, normal, and cut
Tweeter SOOOHZ To 20,000HZ - boost, normal, and cut

POWER HANDLING: Sine wave steady state

75-
POWER
LIMIT 25-
IN I
WATTS .0- ___I_
I I I I
I I I I |
I I I I I
O- I | I I I
20 250 600 3k 4k 20k
FREQUENCY IN Hz .

Avoid operating the speaker system with sustained sine wave signals at power levels
greater than the indicated limits. Permanent damage may result.

POWER HANDLING: Program Material

High energy peaks normal to orchestral music are easily and faithfully reproduced
by the speaker system. These peaks are of relatively short duration and do not
produce the heating effect caused by sustained tone operation. The Stereotech h
speaker system will handle up to ICC watts of orchestral program material. Care
must also be taken to use a power amplifier that has an adequate power rating.

If a low power amplifier is used, the loudest passages may be clipped by the
amplifier. This clipping will cause the speaker to sound distorted. The large
harmonic content of a badly clipped signal can cause excessive heating and
resulting damage to the high frequency speaker elements.

OUTPUT LEVEL

At l meter in a non-reflecting environment, the system will nominally produce an 39dB sound
pressure level when driven with l watt referred to So.

LISTENING QUALITY

Smooth response has been achieved by careful design under controlled laboratory conditions.
The performance of the speakers in your listening room may be influenced to some degree by
the room size, shape, construction, and furnishing. The location of the speakers in the room
will also affect listening quality. The additional features of low distortion and wide dis-
persion will help to provide superior sound in a typical listening environment.

There are two controls at the rear of the system. They provide Z-3dB boost or cut in the
frequency ranges stated in the specifications. For example, a room with heavy furnishings,
drapes, books, and rugs will absorb some of the high frequencies. This may cause the speaker
system to sound dull. The tweeter control would then be placed in the "+ position to conpen-
sate. The controls may also be used to adjust for individual tastes in music.

CONNECTIONS .

Use heavy guage wire (#IS AWE or larger) when connecting the speaker SStem to the
power amplifier. The system leads preferably should have less than 0. ohms resistance
and not more than 0.8 ohms resistance, (62 feet of fll8 wire has 0. ohms resistance.
This corresponds to 31 feet of two conductor wire.)

Be sure to observe polarity when connecting the speaker system and power amplifier

leads to maintain proper stereo perspective.