Allen&Heath 21 Series User Manual

Allen & Heath’s new

stereo 21

SERIES

Allen & Heath proudly unveil their exciting

new range of compact stereo mixers

-

the
21 SERIES. Stylish in looks and superb in
performance, these four models offer outstanding

value for money.

Available in 6, 12, 18 and 24 input versions, the
21 SERIES boasts the useful feature of a separate
mono output derived from the main stereo mix.

Another Plus is the incorporation of an extensive
interface facility to ensure accurate compatibility

with external equipment, and enables two or more

mixers to be linked together for single flexible

operation. A separate power supply unit keeps

nasty hum fields at bay, letting the sound come

through clean and clear.

The 21 SERIES Stereo Mixers by Allen & Heath

are available now.

e

1

ALLEN AN

69 Ship Street
Brighton BNl 1AE
England
Tel,

(0273) 24928

Five Connair Road
Orange) CT 0477
USA
Tel. [phone]

AUDIO QUALITY

Advanced low-noise circuitry boasts a high
slew rate of 13

V/uS,

permitting faithful
reproduction of transient information. Each
mixer is supplied complete with its own
external power supply to ensure that hum
fields are kept to a

minimum. Phantom power
is available as an optional extra. As the
comprehensive PFL system overrides all
monitor outputs and metering, easy checks
may be made on all incoming and outgoing
signals.

MONO OUTPUT

Invaluable as an extra on-stage foldback mix
or as a feed to a mono PA system, permitting
the main stereo faders to be used as
sub-groups or outputs to a stereo recorder.
This feature will be of particular interest to the
AV or broadcast user who may need a
dedicated mono output for simultaneous video
recording, or mono transmission.

PRO AND SEMI-PRO CAPABILITY

21 SERIES mixers are supplied with outputs set

for OVU=

+4dBm,

but external links are

provided so that outputs and tape monitor

inputs can be adjusted by the user (or the
dealer) to ensure compatibility with
equipment designed for lower operating
levels. A thoughtful facility that will make life a
lot easier for the small budget studio. All-steel
construction provides strength and good
electrical screening.

PLUGABILITY

Rear panel sockets provide bus access points
for stereo and mono outputs, cue and echo
sends, and the PFL system. Thus, two or more
21 SERIES mixers may be conveniently linked
for single operation, greatly increasing the
input potential and all-round flexibility of this
new range.

INPUT CHANNEL

*

Electronically-balanced transformerless

FEATURES

microphone input on XLR socket, switchable
to a high impedance balanced line input when
required.

*

Effects insertion point that can also be used

as a line level input or as a spare effects send.

*

20dB pad switch.

*

3

Band equaliser with mid-frequency sweep

from

400Hz

to

6kHz.

*

Pre-fade cue send and post-fade echo send.

*

Channel pan pot and PFL Selector.

*LED peak overload indicator and smooth
travel, long throw fader, providing a high
degree of operator control.

OUTPUT SECTION FEATURES

*

Twin illuminated VU meters with associated

PFL override LED indicator.

*

Two echo returns, each with PFL, cue send,

level and Pan.

*

Cue and echo send masters, both with PFL.

*

Main Left and Right outputs and mono output

on XLR sockets (all featuring PFL selectors).

MONITOR FACILITIES

The two independently-controlled stereo

outputs to headphone and monitor amplifier

can be switched to Mono. An off-tape return

from a stereo recorder may also be selected,

enabling A/B monitoring during recording.

TECHNICAL SPECIFICATION

MIC INPUT

Equivalent Input Noise - 125.5

LINE INPUT

(Further

EQUALISATION

HARMONIC DISTORTION typically
OUTPUT

Recommended load greater than

Maximum output +21dBv

DIMENSIONS Model 621

674x475x100

+20dB

to

+60dB

(PAD

-20dB) 1.5kohm

dBm

-5dB to +36dB (PAD -12dB)

10dB

gain available at fader)

HF

10kHz

(shelving)

MF 400Hz- 6kHz

LF

100Hz

(shelving)

Unbalanced 30 ohm source impedance

458x475x100

Model 1821

891x475x100

10kohm

+/- 15dB

(Q = 1.4)

+/- 15dB

<0.05%

2kohm

Model

+/-

13dB

1221

STEREO 21 SERIES

OWNER'S HANDBOOK

SPECIFICATION:
Construction:

steel main panel and covers, hard stove enamel paint
finish with epoxy ink screenprinted legend.

modular electronic printed circuit assemblies. IC

op-amp and discrete transistor audio system of
transformerless design.

Size& Weight: MIXER

Width

Depth

Height

621 457 476 90mm

(600)

1221 673

(710)

1821 889

(930)

(620)

476 90

(620)

476

(620)

2421 1105 476

(1160)

(620)

90

90

(160)

(160)

(160)

(160)

bracketed figures = in shipping carton.

Connectors: Channel input, stereo and mono outputs;

locking.

POWER SUPPLY: External,

All others

type MPS7

Phantom power option

1/4"

jack.

110-120v or

+48v MPS7P.

220-240v

(Symmetrical system)

Semi-

Weight

9.5kg

(14.0)

14.0

(19.0)

18.5

(24.0)

23.5

(29.0)

3

pin XLR-type

AC.

CONNECTIONS:

FUSES:

OUTPUT =

+15v DC, smoothed and regulated

0.5 amps per rail

INPUT =

AC mains voltage at
220/240v

110/120v

setting =
setting =

50/60Hz

212v to
106v to

250v

130v

AC

AC

30VA max

PHANTOM POWER available as an option (specify MPS 7-P)

=

+48v

DC,

MAINS INPUT = flying
DC OUTPUT = flying 4-core lead

smoothed and regulated at

3-core

lead

1.5m

1.5m

in a

5-pin

pin

XLR female in-line plug.

1

=

-15V

DC

50mA

long

long terminated

pin 2 = 0V
pin 3 = 0V

+15V

DC

PHANTOM POWER (if fitted)

220/240V
110/120V

pin 4 =
pin 5 =

setting = 500mA quick blow 5 x 20mm
setting = 1A quick blow 1 1/4".

GENERAL
All Outputs:

2

Normal Operating Level =

Maximum Output Level =

Output Impedance =

30ohms

+4dBv

+2ldBv 20Hz

to

20kHz

all outputs are protected against damage from accidental short
circuits.

Maximum Gain From Channel Input to Stereo Output:

= +70dB

Frequency Response:

Channel Input to Stereo Output =

30Hz

to

30kHz +/-1dB

Equaliser Characteristics:
HF =
MID =

LF =

15dB

continuously variable at

+/-13dB
and

continuously variable at any frequency between

6kHz.

Q factor =

+/-15dB

continuously variable at

10kHz

400Hz

1.4

100Hz

Total Harmonic Distortion:

Channel Input to Stereo Output typically 0.05% THD

Noise:

20Hz

to

20kHz

MEASURED AT STEREO OUTPUT.

Figures quoted are

noise referred to system operating level.
Microphone Equivalent Input Noise =

Output with Master Faders Closed =

Output with Master Faders Raised,

-125.5dBv

-94dB

ref 0VU

All Inputs Closed better than

-66dB ref 0VU
DIN RMS

621 . . . -68dBm

1221

. . . -66dBm

1821

. . . -63dBm

Output with One Input Raised, mic source

minimum =

-61dB ref 0VU

= 200ohms,

Crosstalk:

Stereo Separation -better than

better than
better than 66dB at

56dB
75dB

at
at

100Hz

1kHz
1OkHz

RMS

EQ flat, gain

Channel Inputs:

3

XLR sockets.

of external phantom power supply of up to

Electronically balanced suitable for safe connection

48VDC.

XLR pin 3 = hot

pin 2 = cold

1

pin

Input Impedance

Gain - mic

line

Pad

-

mic =

= screen

-

mic = 1000 to 1500 ohms

line =

= continuously variable from

= continuously variable from

10kohms

+20dB

-5dB

-20dB

line = -12dB

Insertion Points - unbalanced

1/4"

stereo jack sockets

tip = return
ring = send
outer = earth

normal operating level =

Peak Overload Indicator

-

turns on at 3dB before clipping.

+4dBv

Echo Return Inputs:
mono

1/4"

jack sockets

to

to

+60dB

+35dB

Maximum Gain to Stereo Outputs =

Input Impedance =

greater than 4kohms

+16dB

Stereo Tape Input:

stereo

1/4"

jack socket

tip = left
ring = right
outer = earth

Input Impedance = 40kohms

Gain to Monitors

-

0dB

or

+12dB

selectable by an internal connector

for either +4dBv or -8dBv normal operating level.

Stereo and Mono Outputs:
unbalanced XLR sockets

pin 3 = signal

pin 2 = pin

Normal Operating Level = +4dBv or

-8dBv selectable by an internal

connector.

Cue and Echo Outputs:
unbalanced
Normal Operating Level =

1/4"

jack sockets mono

+4dBv

1

= earth

Maximum Gain from Input =

+10dB