Shure M268 Manual

GENERAL
The Shure Model M268 is a five-input portable
microphone mixer designed for use with sound rein-
forcement, tape recording and audio-visual systems. Its
excellent operational characteristics, compact size,
and functional versatility make the M268 a fine choice
as a primary or add-on mixer in any sound system.
222 H A R T R E Y AVE.. E V A N S T O N . IL. 60204 U.S.A.
AREA CODE 31z/866-zzoo
.
CABLE: SHUREMICRO
TWX: 910-231-0048 T E L E X : 72-4381
The Model M268E is similar to the M268 except that it
is designed for connection to a 210- to 250-volt ac power
line. All information applies to both units except for
references to ac operating voltage, fuse and power line
cord.
DATA
MODELS ~ 2 6 8 AND ~ 2 6 8 ~
SHEET
MICROPHONE MIXERS
M268 Features:
Wide, flat frequency response and extremely low
distortion at full output
Very low line noise and radio frequency in-
terference susceptibility
Four switch-selectable low-impedance balanced or
high-impedance unbalanced inputs
High-level auxiliary input for tape, tuner and
accessories
Individual feedback-type active gain controls for all
five inputs
Master volume control sets overall output level
Simplex power for condenser microphones
High- (unbalanced) or low-impedance (balanced)
microphone-level output matches most amplifier
inputs
High-impedance auxiliary output for high-level
equipment inputs
Direct mix bus for simple mixer interconnection
("stacking")
Ac or external dc operation. Noiseless automatic
switchover to external power in case of ac line
failure
Automatic muting circuit prevents speaker damage
during turn-on and -off
Regulated power supply is unaffected by line
voltage fluctuations
Copyright 1981, Shure Brothers Incorporated
27A80ll (AE)
Compact and lightweight, with rugged, abrasion-
resistant case
M268 (only): Listed by Underwriters' Laboratories,
Inc. and listed by Canadian Standards Association
as Certified
SPECIFICATIONS
Frequency Response
40 Hz to 20,000 Hz, + 3 dB
Voltage Gain (at 1,000 Hz)
(Outputs terminated: rnic 150 ohm133 kilohrns;
aux 47 kilohms; mix bus 3.3 kilohms)
Inputs
I
IMPEDANCE
I
INPUT
I
Designed
for use
with
1
( l ~ ~ ~ ~ ~ ~ l )
1
Input Clipping
Level
Lo Imp Mic Bal or unbal
I
19
to
600
ohms
kilohms
100
ohms to
10
kilohms high-
level unbalance(
I ,000
ohms
1
140
kilohms
I
43
kilohms
1
Depending on control setting
Mix Bus
Distortion
0.2% or less THD from 40 t o 20,000 Hz with lo imp
rnic output at 80 mV level, hi imp rnic output at 1.5V
level, and aux out at 8.OV level
Printed in U.S.A.
3.3
kilohms
3.3
kilohms
+ 8 dBV
(2.5V)