Furman VU-40 Instruction Sheet

FURMAN

SOUND,

INC.

30

RICH STREET
GREENBRAE, CALIFORNIA 94904
PHONE:

(41s)

927-1225

FAX:

(415)

927-4548

----J-

S f S

--

JA7--

- f-

hf fH=---

FU'T'ffS'J

lntroduction

Congratulations

on

your purchase

of a Furman

Sound Model

VU-40 Stereo System

Monitor.

The VU-40 is a convenient rack-

mount dual

channel level monitor

for use in sound reinforcement,

concert sound, recording studio monitoring, or in

any application

where a

quick

visual check of

system

performance

is

desirable.

VU-40 Features

O

Two independent metering

channels

O On/off transient

muting

function

protects

speakers
O Familiar VU meter scales
O

Greenl/ellodRed LED color coding

O

Peak

or

Average response

switch

O

Line Level/Power

Out switch for each channel

O Line Level may be set to

-10,

0, or

+4

dBu

O Sixteen

Power

Out choices from 20

to

1260

Watts

O Ground lift, on/off switches

Operation

Front Panel

The VU-40

is comprised

of two 20 LED bar-graph meters,

cali-

brated

in dB like standard VU

meters. They may

be set with

the

pushbutton

switch on

the

left

side of

the

front

panel

to read either

Peak

(button

in)

or Average

(button

out)

response.

The

two me-

ter scales above the LED's

are used

for

Average, while

the two

scales

below

are

for Peak.

Because

audio signals are AC

(alter-

nating current), their actual voltage level

varies from millisecond

to

millisecond.

"Average"

refers

to the average magnitude during

a time span of about

1/4

second. To approximate

the action

of a

traditional

electromechanical VU

meter, choose

the Average

set-

ting. Average

also

gives

a

good

indication

of the

perceived

loud-

ness of the signal. The Peak

setting indicates

the

highest

point

of

the

waveform, regardless

of the average. Therefore,

the Peak

position

will

always result in higher readings,

but it will

give

a truer

indication

of

how

close the signal is

to clipping.

Rear Panel

The Input

Select switches

on the rear-panel

select either Line

(line

level) or Amplifier

(power

output),

allowing

you

to monitor

ei-

ther the

inputs

or outputs, respectively,

of a

power

amp. Since

each channel may be switched independently,

another

possibility

is to use one VU-40

channelfor input

and the other for output.

Of

4-9532

course, the

Line setting

may be used to

monitor

any

line level

sig-

nal, even

if no

power

amp

is involved.

For

Line, the

"zero"

meter

positions

may be set

to either

-10,

0, or

+4 dBu with the Line Input

slide switch.

This

switch

controls both the

left and right channels

(assuming

both are set to

the Line

position

with

their

Input

Select

switches).

For line

level metering,

refer

to the

white

scales on the

front

panel,

which are

calibrated in decibels.

The

choice of

-10,

0,

or

+4 depends on the

nominal

line level

of the

other

equipment

in

your

system, especially

the

mixer

and

tape recorder. lf in doubt,

consult the manuals

for that equipment.

When either or

both of the

Input

Select switches

are set to

Amplifier, the

VU-40

is ready to monitor the output(s) of a

power

amp.

The blue scales,

calibrated

in

percent

of

full

power,

are

used.

There are

16

power

output choices

from 20 to

630

watts for

8 ohm

loads,

or

f rom 40 to

'1260

watts tor 4 ohm loads. Check

the

maximum

power

output

for

your

amplifier

and the rated impe-

dance

of

your

speakers

to determine

which range

to

use. The

ex-

act wattage corresponding

to

100

percent

is determined by the

settings of

the four

Amplifier Power switches, according to the

fol-

lowing table. The switches

are shown as seen

at

the

rear

panel,

from left

(closest

to

Power Amp binding

posts)

to

right.

In adjusting system

levels, the

VU-40's meters

serve

as a

guide

to avoid overdriving

the

power

amplifier,

which

can

result in

Amplifier

Power

Switches

When

switches

are set as

follows:

The 100o/o reading in watts i,

Left
down down

down

up down

down

down up down

up up down

down down up

up

down up

down up

up

up up up

down down

down

up down

down

down up

down
up up down
down down

up
up down up
down up up
up

up up

Right Sohms

4ohms

down

20 40

down

25 50
down 32 64
down

40

80

down 50

100

down

63 126
down

80 160

down 100

200

up

125 250

up

160 32O

up

20O 400

up

250 500

up

320

640

up

400

800

up

500

1000

up

630

1260

960020-609

clipping

distortion.

The amplifie/s

output

should

only

rarely

be al-

lowed to exceed

1000/"

of

its rated

power.

The meter LED's

are

cofor coded

red

above

100% so

you

can see overloads

at a

glance.

When only

green

lights

show,

the

amp is operating

in a

safe

range.

In between,

there are

three

yellow

lights

warning that

the

signal

level is

close

to overdriving.

Transient

Muting

A special

VU-40 feature is turn-on/turn-off

transient

muting.

To use

it, line

level feeds to the

power

amp

are routed

first

to

the

VU-40, then

back

out to the

power

amp.

When AC

power

is ap-

plied

or

removed, the

power

amp

feed will be

muted for one sec-

ond,

eliminating

loud thumps

with their

potential

for speaker

dam-

age.

With a

VU-40 channel assigned

in this

fashion to each

power

amp

in a system, the

entire system

may

be

switched on

and off

with one

master switch,

providing

an extra degree of

pro-

tection

for

systems

operated

by

inexperienced

personnel.

lnstallation

The

VU-40's

connectors

include both a

1/4 inch

phone

jack

and

an

RCA

jack

for

Line

Level input

and

output

for each

channel.

lf the

VU-40

is to be

used only

for line level monitoring, only

the

input

jacks

need be used.

However, since

this

might necessitate

splitting

the

signal

to be

monitored with a

Y-cord or similar device,

you

may

find it more

convenient

to use the

VU-40's output

jacks

as well,

routing the signal

in and then back

out. This

method

also

provides

the benefit

of the

transient

muting feature.

lf desired,

both the

phone

and the

RCA

output

jacks

can

be used simultane-

ously.

This can

be useful

for signal splitting,

if, for instance,

you

want to

route the signal

to

more than one

power

amp. However,

only one

of the two

input

jacks

on each channel

should be used

as

an

input

(the

two

jacks

are connected together,

so the other

jack

can

be used

as an output,

but

it

will

not have the one second

mute).

For best

results, all cables carrying

line level

signals

should

be shielded.

For

Power monitoring, a

pair

of banana

jacV

binding

post

ter-

minals

are

provided

for each channel.

The banana terminals are

balanced,

floating, and

isolated, so that the

VU-40

can

be

safely

connected

to any

power

amp output without

regard for

polarity.

These cables

do not

need to be shielded.

Warning: To

avoid

damage

to the

VU-40, do not connect a

power

amp output to any

phone

or

RCA

jack.

Power

amp outputs

or speakers must con-

nect only

to the binding

posfs

labeled

"Power

Amplifier."

It is

possible

to use the

VU-40 for Power monitoring and still

use the

transient

muting feature. Simply

connect the

power

amp

outputs to

the banana

jacks,

set the

lnput

Select

switches to Am-

plifier,

and

route the

line level signal at the

point

to be

muted

(generally

just

before the

power

amp or crossover,

if

used)

into

and out

of the

phone

or

RCA

jacks.

The

VU-40 is intended

for mounting in standard

19"

equip-

ment

racks. A logical spot to

install it would be

just

above the

amp

whose output

it is monitoring. Standard

racks

come equipped

with mounting

rails with

holes

tapped

for 10-32 machine screws.

Be

sure

to use

only 10-32 screws

(in pailicular,

avoid 10-24

screws,

which

will fit if forced but will strip the threads).

To avoid

marring the

panel

when

tightening

the screws, use

nylon washers

under

the screw

heads.

Ground

Lift Switch

In many

installations, hum-causing

ground

loops

are

formed

by the

common connection

of various

pieces

of equipment to

the

power

line

ground,

and by contact between chassis, as

in a rack

with metal

rails. Sliding the

ground

lift

switch

up completely

iso-

lates

all

signal

grounds

from the chassis, breaking

any

ground

loops.

The

chassis

always

remains

connected

to the

ground pin

on the

AC cord

for

safety

and to

provide

shielding

against RF

in-

terference.

Balanced

Option

lf the balanced

option

has

been

installed

(Model

VU-408)'

XLR connectors

will

be

present

on

each

channel

for both

inputs

and

outputs.

Balanced

lines offer

the

benefits

of

cancellation

of

hum,

noise,

and

RF

interference

which

may

be

picked

up

in

the

interconnecting

cables.

For balanced

connections,

shielded

twist-

ed

pair

cable

must

be

used.

lf

desired,

the

XLR

(balanced)

and

phone (unbalanced) outputs

may be

used simultaneously.

How-

ever, only

one of

the

two

inputs

should

be used.

Limited

Warranty

The

Furman

VU-40

is

warranted

against

failures

due to

defec-

tive

parts

or faulty

workmanship

for a

period

of one

year

after de-

livery to the

original

owner.

During this

period,

Furman

will make

any

necessary

repairs

without charge

for

parts

or

labor- Shipping

charges

to the

factory

or

repair station

must

be

prepaid

by the

owner;

return shipping

charges

(via

UPS Ground)

will be

paid

by

Furman.

This

warranty

applies

only

to the

original

owner

and

is not

transferable.

Also,

it does'not

apply

to repairs

done

other than

by

the

Furman factory

or

Authorized

Repair Stations.

This warranty

shall be

cancelable

by

Furman at

its sole discre-

tion

if the

VU-40

unit

has been

subjected

to

physical

abuse

or

has

been

modified

in any

way

without

written

authorization

from

Furman.

Furman's

liability

under

this

warranty

is limited

to repair

or

replacement

of

the defective

unit.

Furman

will

not be

responsible

for incidental

or consequential

damages

resulting

from the

use or

misuse of

its

products.

Some

states

do not

allow the

exclusion

of incidental

or consequential

damages,

so

the above

limitations

may

not apply to

you.

This

warranty

gives you

specific

legal

rights, and

you

may also

have

other

rights

which

vary from state

to state.

Warranty

claims

should

be accompanied

by a copy

of the orig-

inal

purchase

invoice

showing

the

purchase

date

(if

a

Warranty

Registration

Card

was

mailed

in

at

the time

of

purchase,

this is

not

necessary).

Before

returning any equipment

for repair,

please

read the

important

information

on service

below.

Service

Before

returning

any equipment

for repair,

please

be sure that

it

is adequately

packed

and

cushioned

against

damage

in

ship-

ment, and

that

it is insured.

We suggest

that

you

save the

original

packaging

and

use

it to ship

the

product

for servicing.

Also,

please

enclose

a

note

giving your

name,

address,

phone

number

and

a description

of the

problem.

NOTE: All

equipment

being

returned

for

repair must

have a

Return

Authorization

(R/A)

Number.

To

get

an

R/A Number,

pfease

call

the

Furman Service

Department,

(415)

927-1225,

be-

tween

8

am and 5

pm

U.S.

Pacific

Time.

Please display

your

R/A

Number

prominently

on

the

front of all

packages.

VU-40 SPECIFICATIONS

LINE

IwOUT

Input

lmpedance:

Greater than

200K

ohms.

Sensitivity

for 0

VU:

-10

dBu

(.245

Vrms) or 0

dBu

(.775

Vrms) or

+4 dBu

(1.23

Vrms)

Turn-on Delay:

APProximatelY 1 Sec

Max.

Through Level:

+22 dBu

(10

Vrms)

Connectors:

VU-40: 1/4"

phone

and

RCA

VU-40B:

Phone, RCA, and

XLR

POWER

AMP Input

lmpedance:

Greater

than

200K ohms.

INPUTS

Sensitivity

for 0

VU:

16

switch

selectable

calibrated

sensitivities

for

either

20 to 630

Wafts

at 8 ohms,

or

40

to

1260 W at 4 ohms

Connectors:

Banana binding

Post.

METERS

Accuracy:

+0.5 dB

(factory

set

internal trim

pot).