Baldwin Boxall BVMX Operating instructions

Brand: Baldwin Boxall

Model: BVMX

Type: Operating instructions

Baldwin Boxall Communications Ltd.

Wealden Industrial Estate, Farningham Road

Crowborough, East Sussex, TN6 2JR

Telephone: 01892 664422 Fax: 01892 663146

Website: www.baldwinboxall.co.uk

Email: mail@baldwinboxall.co.uk

IBVMX

Issue 4 12/01/1999

BVMX Mixer and

BVMS1 Mixer Output Module

Operating Instructions

- 2 - Issue 4

BVMX MIXER

The BVMX will accept up to a maximum of 11 single width input or output modules, for example 10

input modules and 1 output module. A 6 way dual in line switch enables the signal buses to be

isolated thus providing two independent output channels between module 5 and 6. Using this switch it

is easy to realise a two output channel mixer with input modules occupying positions 1-4 and the

output module in position 5, input modules in position 6-10 and the output module in position 11. It is

possible to obtain further output channels by carefully drilling out the appropriate through hole

connection adjacent to the pin of each input edge connector.

Two separate two pole changeover relays provide switching of external AC or DC signals up to 100V

at 5 Amps maximum, for busy indicators, volume restoration relays etc. Also available on each 8 way

connector is +24V and 0V at 1 Amp maximum to power external circuits. If "Rest" is selected "Off"

on the DIL switch relay RLY1 will only operate from module sockets 1-5 and relay RLY2 will operate

from 6-11. When the "Rest" is selected "On", both relays will operate from all module sockets.

Please refer to data on IMP modules.

The BVMX obtains 24V DC power from a PSU/Charger BVPS and maybe powered by two separate

sources to ensure operation. The mixer may also be used as a stand alone mixer and interfaced with

other equipment. To power it use the BVMXPSU power supply. These supplies are presented by a

two way crimp terminated locking connectors. Front panel LED indicators illuminate when the

associated supply is present.

Depending on the input module fitted and the selection of its internal switches the audio output signal

may be routed to one of two bus lines. The output module type number BVMS1 has a virtual earth

mixer stage connected to each of these audio signal paths. It is possible by switch selection to achieve

priority on audio highway PA Pin No 5 Channel 1 over audio highway Channel 2 on Pin No 4.

Channel 1 the priority channel incorporates a switchable low pass filter at 12KHz and the output may

be routed direct to the output or via the bass and treble control. Channel 2 incorporates a high pass

filter switchable at 300Hz and its output is routed via the tone controls to the output. Each channel has

its own independent master gain control which are presented on the front panel. The access terminal

of the rear panel connector that the output stage occupies may be switched to either:

1. A pre-fade output from channel two for tape recording,

2. DC controlled access channel one over channel two, connect to 0V to enable channel 1,

3. An unbalanced audio output when this module is fitted in the standard Adept amplifier main

frame,

4. DC controlled remote volume when the remote volume control option is fitted.

Three four way connectors enable options to be inserted in the following positions:

A. Channel 1 before the master gain control J2.

B. Channel 2 before the master gain control J3.

C. After the bass and treble control stage J4.

Another four way connector J1 is provided which enables the use of the virtual earth mixing stages as

buffers to feed additional output stages, for example a system that requires a number of ambient noise

sensors feeding independent areas. Switches associated with the input of the virtual earth amplifier

provide the correct attenuation when used in this mode.

Each output module has 4 LEDs to indicate the output level, 5% 50% 100% and 120% the nominal

output level i.e. 100% is 0.775V but signals to a maximum of 2.5V is possible.

- 3 - Issue 4

SW2 SWITCH FUNCTIONS

1. PRI - set to 'ON' for priority.

Channel 1 when accessed will override Channel 2.

Note: to access Channel 1 select ACC switch 'ON' and connect access terminal to 0V.

Set 'OFF' to mix both channels together.

2. LP - set 'on' to by pass the 12KHz low pass filter on Channel 1.

3. * OUT - set to 'ON' to provide an unbalanced output from the access terminal or output to feed the

power amplifier when fitted in an Adept mixer amplifier.

Note: set (4) ACC and (5) PF to 'OFF'.

4. * ACC - set to 'ON' for priority access. Used in conjunction with PRI above.

Note:- set (3) OUT and (5) PF to 'OFF'.

5. * PF - set to 'ON' to provide a prefade output from Channel 2 for tape recording etc.

Note: set (3) OUT and (4) ACC to 'OFF'.

6. TC - set to 'ON' to route Channel 1 direct to the output, not via the bass and treble controls. Note: set

(8) TC to 'OFF'.

7. HP - set to'ON' to bypass the 300Hz high pass filter on Channel 2.

8. TC - set to 'ON' to route Channel 1 via the Bass and Treble controls.

Note: set (6) TC to 'OFF'.

* ONLY SET ONE SWITCH TO THE 'ON' POSITION

SW1 SWITCH FUNCTIONS

1. Set to 'ON' for virtual earth (summing) input, normal mixing mode on Channel 2.

Set to 'OFF' for high impedance input, when used in the buffer mode.

2. Set to 'ON' for virtual earth (summing) input, normal mixing mode on Channel 1.

Set to 'OFF' for high impedance input, when used in the buffer mode.

12345678

OUT

ACC

Sw 1

Sw 2

SIGNAL PROCESSING OPTIONS

Channel 1 before master control

Channel 2 before master control

After Bass & Treble Controls

DC Volume Control

Connector BVMS2

Bass Treble

Sw 2 Switch

Functions.

Channel 1 OUT

Channel 2 OUT

See text Input Stage in/out

OFF = Buffer

Input Mode ON = Mixing

Channel 1 Master

Channel 2 Master

Pull Knob to Remove

PRI

Channel 2 IN

Channel 1 IN

Fig 1: BVMS1

Connector and

Selector Locations

- 4 - Issue 4

The BVML Module

The BVML module allows external access to the internal Priority, Busy and Chime bus lines within a

BVMX mixer mainframe. This enables equal (first come first serve) priority to be achieved when

multiple mixers are used.

As the internal bus employs static sensitive logic devices the BVML incorporates the essential

protection components.

A BVMS1 mixer module is required in each of the BVMX mainframes to obtain the audio output. We

do not recommend or provide the facility to parallel the low level virtual earth mixing, audio bus lines

from one BVMX to another, due to hum, noise and instability problems that could occur. Mixing of

the BVMS1 outputs is easily achieved by connecting them in series.

The BVML occupies one module space and presents the internal bus on the 4-way BVMX connector

shown below.

BVMX Rear Panel Connector BVMX Internal Bus

A Busy

B Chime

0V 0V

Access Priority in/out

Figure 5 illustrates a system using three BVMX linked via BVML providing 25 microphone inputs,

one having total priority, 24 with first come first serve priority and an IMP33 pre-announcement

chime.

Edge Connector

180k

Gate Option

180k

Gate

Input

mixing

bus

CHANNEL 1

+20V

LOGIC

Priority 1

Sw 2

Input Stage in/out

Sw 1* 2

Sw 1* 1

Low

Pass

Sw 22Master

Sw 2

Option

CHANNEL 2

Pass

Sw 2

High 7

Master Prefade

Access

Out

Sw 2

DC VC

Option

Bass &

Treble

Controls

BVMS2

Output

Level

Indicator

120%

100%

50%

BVMX Connector

Access Ground BA

in/out

7321

+20V

* Select buffer mode

Fig 2: BVMS1 Block Diagram

- 5 - Issue 4

IN A

IN B

20V+VE

ACCESS

CHIME

BUSY

REST

PRI. IN

PRI. OUT

EARTH

1 0

1 1

1 2

1 0

1 1

1 2

1 0

1 1

1 2

1 0

1 1

1 2

1 0

1 1

1 2

1 0

1 1

1 2

1 0

1 1

1 2

1 0

1 1

1 2

1 0

1 1

1 2

SELECT 'ON' TO

JOIN 1-5 TO 6 -1 1

Drill to break bus line

between 4 and 5

CHIME

BUSY

REST

PRI

BALDWIN BOXALL COMMUNICATIONS LTD

INPUT B

DC SUPPLYDC SUPPLY

INPUT A

RLY 1RLY 2

CHANNELS 1-5CHANNELS 6-11

CONN

+VB

+VA

0VCONN

CONN

123456

PC 1116

MODULE CONNECTORS

INPUT/OUTPUT CONNECTORS

REG 2-7

+20V INPUT/OUTPUT

MODULESREG 1

+24V OUT

Supply LEDs 1 & 2

mounted on PC 1122

4321

1 1

1234567891 01 1

1234567891 0

11109876543

SUPPLY INPUTSUPPLY INPUT

0V +24V

BUSY/VOLUME RESTORATION OUTPUT

CONTACTS 5A MAX

CHANNELS 6-11+24V OUTPUT 1A MAX

CHANNELS 1-5

+24V 0V+24V 0V

AERIAL 1

AERIAL 2

0V GROUND

ACCESS ETCSIGNAL

IN/OUT

INPUT/OUTPUT

CHANNELS

BALDWIN BOXALL COMMUNICATIONS LTD. ENGLAND TEL 01892 664422

9 way D connector

providing fault output

is fitted

when IMP9, IMP41 etc.

Aerial coax socket

when IMP11 is fitted

Input/output connectors

ACCESS ETC

0V GROUNDA

BSIGNAL IN/OUT

Fig 3 (above): BVMX Plan View

Fig 4 (right): BVMX Rear View

- 6 - Issue 4

INPUTS 2-9

SET FOR EQUAL

(FIRST COME FIRST

SERVE) PRIORITY

AND CHIME

SIGNAL

IN/OUT

GROUND

ACCESS

SIGNAL

IN/OUT

GROUND

ACCESS

IN/OUT

GROUND

ACCESS

SIGNAL

IN/OUT

GROUND

ACCESS

12 1011

WILL OVERRIDE

ALL OTHER INPUTS

SIGNAL

1891011

IMPX IMPX BVMLIMPX

SET FOR CASCADE

PRIORITY & CHIME

BVMX

PLAN

VIEW

CHANNELS 1-5 CHANNELS 6-11

BUSY/VOLUME RESTORATION OUTPUT

PRIORITY

CHIME

BUSY

INPUTS 2-9

SET FOR EQUAL

(FIRST COME FIRST

SERVE) PRIORITY

AND CHIME

SIGNAL

IN/OUT

GROUND

ACCESS

SIGNAL

IN/OUT

GROUND

ACCESS

IN/OUT

GROUND

ACCESS

SIGNAL

IN/OUT

GROUND

ACCESS

12 1011

SIGNAL

1891011

IMPX IMPX BVMLBVML

BVMX

PLAN

VIEW

CHANNELS 1-5 CHANNELS 6-11

BUSY/VOLUME RESTORATION OUTPUT

INPUTS 2-9

SET FOR EQUAL

(FIRST COME FIRST

SERVE) PRIORITY

AND CHIME

SIGNAL

IN/OUT

GROUND

ACCESS

SIGNAL

IN/OUT

GROUND

ACCESS

IN/OUT

GROUND

ACCESS

SIGNAL

IN/OUT

GROUND

ACCESS

12 1011

SIGNAL

0dB OUTPUT

1891011

IMPX IMPXBVML IMP33

CHIME

BVMX

PLAN

VIEW

CHANNELS 1-5 CHANNELS 6-11

BUSY/VOLUME RESTORATION OUTPUT

PRIORITY

CHIME

BUSY

PRIORITY

CHIME

BUSY

BVMS1

BVMX

Fig 5: Connection

details for Three

BVMX Mixers

linked via BVML

Modules,

providing 25

Microphone

Inputs with Chime

Baldwin Boxall BVMX Operating instructions

Baldwin Boxall BVMX Operating instructions

Baldwin Boxall BVMX Operating instructions

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