OPERATION
lnput lmpedance (at 1 kHz)
Resistance: 50 kilohms
Capacitance: 160 picofarads
Output Impedance(at 1 kHz)
High Level: Less than 2000 ohms (minimum recom-
mended load is22,000 ohms)
Low Level: 600 ohms (any load on Low Level output
will not affect input clipping level)
Power Consumption
5 watts
Operating Voltage
120 or 240 volts ac
+
1O0/0,50160 Hz (internally selec-
table)
Temperature Range
Operating: -7" to 57" C (20" to 135"
F)
Storage: -29" to 71
"
C (-20" to 160"
F)
Dimensions
See Figure 2
Net Weight
986 grams (1 Ib2-112 oz)
144mm 104mm
r(5-9/16
IN.
)
1
(4-3/32 IN.I~
OVERALL DIMENSIONS
FIGURE
2
INSTALLATION
To reduce the risk of fire or electric shock, do
not expose this appliance to rain or extreme
moisture.
The M64A can be operated on any flat surface, or
(with adequate space) be mounted to an amplifier
chassis or cabinet using screws through the M64A's
mounting flanges. The unit can be mounted inany posi-
tion for normal operation, but for best results, itshould
be locatedaway from motors, lightingdimmers,or other
hum-producing power sources and away from intense
heat sources.
Should hum be encountered in a sound system or
installation, one or more of the equipment power plugs
may be reversed to reduce hum. If the turntable has a
grounding lead, this wire can beconnected to the M64A
Ground screw to reduce hum pickup.
WARNING
Use of the M64A with power amplifiers of the
transformerless (ac-dc) type may result in a
shock hazard. A suitable power line isolation
transformer should be used with such equip-
ment.
1. Set the selector switch to the desired function
(Phono,Flat or Tape).This automatically selects the
proper equalization (frequency response) for both
channels.
2. FortheequalizedPhono(RIAA)or Tape (NARTB) posi-
tions, connect the signal leads from the phono car-
tridge or tape head tothe M64A jacks markedChan-
nel
1
lnput and Channel 2 Input. Note that the Flat
position can be used for phono cartridge or tape
head buffering applications in which the M64A out-
put is connected to an equalized amplifier input.
3. For the Flat position using two high-impedance
microphones, connect each microphone cable to
one of the M64A lnput connectors. If a single high-
impedance microphone is used, connect it to either
lnput connector. NOTE: If low-impedance
microphones are to be used, a suitable line match-
ingtransformersuchas Shure'sA95 Seriesshouldbe
used.
4. Refer to the phono cartridge, tape head or
microphone data sheet for details on connections,
phasing and grounding.
5. Connect the Channel 1 and Channel 2 Output jacks
(Highor Low Level)tothe corresponding input jacks
of the power amplifier, preamplifier, tape recorderor
mixer. The High Level outputs can be connected to
high-level auxiliary inputs, and the Low Level out-
puts can be connected to low-level microphone in-
puts (or equalized phono or tape head inputs inbuf-
fering applications).
6. If grounding isnecessary,theassociatedequipment
ground lead can be attached to the M64A Ground
screw.
7.
Insert the M64A power line cord intoa proper power
outlet (120 Vac +lo%, 50160 Hz), preferably one
controlled by the power amplifier's on-off switch.
Make certain the M64A Power switch isturned on if
the unit isto be remotely turned on and off.
SERVICE
WARNING
Voltages in this equipment are hazardous to life.
Refer servicing to qualified service personnel.
Balanced Line Output
For professional low-impedance balanced-line use
such as broadcast systems or recording consoles, an
external line matching transformer such as Shure's A95
Series can be added to each M64A High Level output.
The resultant output level isapproximately -32 dBm. If
2
