Sparta AS -30B User manual

www.SteamPoweredRadio.Com

SPARTA

AS

-30B

AUDIO

CO

SOL

TECH

!CAL

'1.AN

AL

www.SteamPoweredRadio.Com

MIXERS:

INPUTS:

OUTPUTS

:

F i

ve

AS -

308

CONSOLE

SPEC

I

FICATIONS

Nine

stereo

pairs;

On

e

each

for

MLxers

l

through

4

and

five

for

Mixer

5,

plus

exte

rnal

AIR

input

.

Low-l

eve

l;

-

55

db

nominal

from

150/250

ohms

(50

ohm

selected

by

j

umper),

standard

on

Mixer

l

(optional

for

Mixer

2).

Hi

-l

evel;

-10

dbm

nomina

l

from

600

ohm

source,

stand

a

rd

on

Mixers

2

thr

ough

5. S

ee

note

1.

AI

R;

D

epends

upo

n

ex

t

erna

l

monitor-amp

.

Program;

8

dbm

into

bal

an

ced

600

ohms

at

0

vu

.

22

dbm

max

.

Au

dition;

8

dbm

nominal

into

600

ohms

single-ended

.

(from

60

ohm

so

u

rce

.

See

note

2).

Monitor;

lv

nomin

al

into

hi

-Z l

oad.

Cue;

O.

lv

nomin

al

into

hi-Z

lo

a

d.

Phone

s ; 1

mw

nomin

al

into

-lOK

ohms.

FREQ.

R

ESPONSE:

A

ll

outputs

less

t

han

2db

down

,

20

Hz

to

20

kHz

.

NOISE:

D

ISTORTION:

C

Ra3STALK:

POWER:

SIZE:

SHIPPING

WT:

MUT

I

NG

:

NOTE

:

1:

NOTE

2:

Bel

ow

65

db

at 0

vu

out

with

-

55

db low

level

input

Bel

ow

75

db

a t 0

vu

out

with

-10

dbm

hi

-level

input

A

ll

outputs

less

than

0.

5%

THO

at

norma

l

operating

levels

.

L

ess

than

1%

THO

a t

max

outputs

.

Below

nois

e

in

a

ll

channe

ls

and

modes

117

/234

vac

,

50/60

Hz.

W , 15

1/2";

H,

6

5/8"

; D,

10".

24

lb

s

(incl.

pwr

.

supply

)

Switch

clo

s

ur

e

to

rear-panel

t

erm

inals

from

!\ILxers l

to

3,

clos

ed

in

Aud

. &

Prog.

modes

for

control

of

external

DC

relay

s .

H

i-le

ve

l

inp

uts

_ar e

balanced-bridging

to

allow

individual

termination

of

input

lines

;.it

rear

panel,

if

required

.

Permits

constunt

lin

e

lo

:id

pl

us

u

se

of

higµ-imp

c

dance

sources

.

I

dentic

al

line

amplifiers

for

·

Prog

r

am

and

Audition

outputs

.

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SPARTA ELECTRONIC CORPORATJON

D

ear

Customer,

C

are

fu

l

attent

ion

to

QuaJity

Control

is

an

other

important

element

in

our

daily

effor

t to provide you

with

excellence

of

product

and

service.

At

SP

AR

TA

each

pi

e

ce

of

equjpm

ent

and

sub-as

se

mbly

receiv

es

numerous

in

spect

ions and

te

s

ts

in

th

e p

rocess

of p

rod

uction.

Th

e final

result

s

must

m

easu

re

within

our

exact

ing

requirements

before

it

is shipped

to

you.

Listed

below

are

just

a

few

of the

major

check points and

tests

this

particular

pie

ce

of e

qwpment

has

r e~eivcd be

for

e

be

ing

prepared

f

or

shipmen

t. Should you note any

discr

epa

ncy

in

the

appearance

or

operation of

your

SPARTA

Pr

oducts

or

if

you h

av

e

any

gene

ra

l

comments

as

to

how

we

might be of

greate

r

service

,

your

suggestions

will be

gr

ea

tly

appreci

ated.

AS-308

Custom

er

:

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l:rp

SERIAL

NO._--'-J_______.._f_.'

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DATE:

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(1-r,1-

PWR

. SUP. SERIAL

NO:

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(7

CAL.

BY

✓

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U<.....Q

No. OF

PREAMPS

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--~---

----=

=-

----

OUTPUT DISTORTI

ON

SIGNAL/NOISE

PHASE

CH

..:

lL:

<~

, / ':i

-%

r,',

q ·

+ dbm -db

.r.t.

I,

CH-

lR

: +

,_

/ ,

dbm

I 7z; %

C;

y

db

CH-lL

Freq.

Resp.

-2db

at

Hz

-2db

at

KHz

l

KHz

Ref

.

--------

CH-lR

Freq.

Resp.

-2db

at

Hz -2db

at

KHz

--------

MONO

-S

TEREO MIC.R & L MONO-STEREO OUT CROSSTALK

CH-2L

+

/'-

..

0

dbm

I

/4

%

-r

/".

db

CH-2R +

,-,~

dbrn ' 1~ %

2'

'?('

db

Fr

e

q.

Resp.

CH-2L I 1

11

-::;:- 2

~

l(

CH2-R

11'

- )

/'l{

L

evel

CH-3 L +

~

d

bm

~

L& % /

9'

db

CH-3 R +

dbm

I I

-1-

%

/Y

db

Freq.

Resp

.

CH-3L

z.u

-2

(f

f{

CH3-R (

7-

:;

Cit

(

CH-4

L + <..

""~

V

dbm

,,

I

2-

% )

'-1

db

CH-4 R + <~,;- d

bm

.,

LI_

% ,

--

-v

db

Freq.

Resp.

CH-4L

I.Cf

?,

r A

CH4

-R I -

,-;

--:.,.~

I

CH-SLATh

.E

+

..,.

~-----

£:'.'

dbm

" )7 % , D db

CH

-5

R

l',..

Th

. E +

c..~

dbm

7'7

%

~

~.

db,

.,

,,

Fr

eq,

Resp

. CH-SL

?-(.I

- 2

':J''l[

CHS-R

/_

..

~

-2

..

{r

I

-•'

t

(..,

Audition L +

,.

,~

dbm

I

I'}_

% ~

ZtJ

db

Output R + C

dbm

~

I u %

db

Monitor Air R & L L

Pr

og R & L t. Aud R & L

-----

--

-----

P

HONE

CUE

MUTING

---------

----~-

--

----------

TEP-3S

ASC-30

5B

Wow

&

Flutt

er

RTT

Calib

by

Ca

rt.

------

-

---

LTT

3/29/71

www.SteamPoweredRadio.Com

GENERAL:

AS-30B CONSOLE

DESCRIPTION

The

AS-30B

is

a

desk-type

Stereo

Audio

Conso

le

featuring

five

mixing

channels

with

push-but

ton-selected

multiple

inputs

for

Mixer

5.

As

normally

supplied,

the

first

mix

er

inclu

des

low-l

evel

preamplificrs

for

50

to

150

ohm

microphones

and

the

rem

aining

four

arc

supplied

with

high

-

level

balanced

inp

ut

transformers

.

The

inp

ut

transform

ers

for

ML"'<.er

l

are

located

on

cards

tb

allow

replacement

with

another

pair

of

low-l

evel

preamplifiers.

The

hi

gh

-l

evel

i

nputs

are

balanced

bridging,

wh

ich

avoids

the

source

l

oading

of

th

e

typical

600

ohm

i

nput

and

greatly

increases

the

flexibi~~ty

of

the

console.

In

the

very-

rare

in

stance

where

a

600

ohm

termination

is

required,

it

is a

simple

matter

to

add

a

pair

of

620

ohm

resistors

across

the

line

at

either

the

source

or

lo

ad

end

.

Some

sources,

such

as

Ampex

and

TEAt,

provide

for

this

int

ernally.

When

operating

from

sources

intended

for

single

-

ended,

high-impedance

lo

ads

,t

he

minus

input

terminals

of

th

e

consoles

are

connected

to

the

shield

and

the

conso

le now

appears

as

a

single-ended

h

igh

-i

mpedance

(l0K)

load

.

T

he

Audition

and

Program

Amplifiers

in

the

AS-30B

are

id

entica

l

and

interchangeable

.

In

the

Audition

side

,

the

li

ne-amplifier

gain

is

de~ermined

by

internal

resistors

and

is

set

to

provide

approximately

the

same

l

eve

l

output

as

the

Program

side

with

normal

· g

ain

control

settings

.

The

audition

output

terminals

are

fed

directly

from

the

audition

lin

e

amplifiers

from

a

single-ended

source

impedance

of

60

ohms.

The

audition

out

-

put

is

then

capable

of

driving

multiple

l

oads

with

little,

if

any

attenuation.

The

input-so

urce

selection

for

Mixer

1 is

via

a

push-button

assembly

which

allows

more

than

one

source

to

be

selected

simultaneously

.

This

feature

,

if

used

judiciously,

will

permit

more

d1an

one

source

to

be

mixed

simultaneous

ly

on

the

one

mixer

pot.

If

this

is

attempted,

the

individu

al

source

levels

must

be

adjus

t

ed

externally

but

.

th

e

console

will

not

lo.id

either

source

·.

It

must

be

considered

,

however,

that

each

-1-

www.SteamPoweredRadio.Com

AS

-3013

D

escription

(con

t'd)

of

t:wo

sources

will

then

be

loaded

by

the

other

,

and

suitable

isol

atio

n mu

st

be

pr

ovi

ded,

if

requi

red

.

INSTALLATION:

Input

and

Output

Connections,

wit:h the

exception

of

the

Mixer

1

XLR

co

nnectors

,

are

made

vi

a

rear-panel

b::irri

er

strips

.

Spade

lu

gs

or

fanning-strips

are

n

ot

required

s

in

ce

the

barrier

st

rips

arc

d

es

igned

with

captiv

e

plates

to

easily

accommodate

severa

l

str

ip

ped

wires

per

termin

al,

either

solid

or

stranded

.

Rear

p

ane

l

connections

aJ:c

clearly

id

en

tified to

facil

i

tate

installation

without

resorting

to th

e

manual

or

to

a

numbered

diagram

.

Audio

connecti

ons

are

norm

a

lly

made

with

twisted-pair

,

shie

lded

cab

le

such

as

Be

l

den

8737 (

strand

ed)

or

8739 (

solid

),

Either

may

be

us

e

d,

although

it

is

generally

more

sa

ti

sfactory

to

use

solid

wire

in

a

permanent

i

ns

t

allation

·where

flexibility

is

not

r

equired

since

solid

wi

re

is

eas

i

er

to han

dle

and l

es

s

apt

to

i

nadvertently

short

to

an

adjacent

terminal.

S

ingle-ended

outputs

and

in

puts

can

use

the

same

type

cable

by

simp

ly

clippin

g off

d1e

unused

conductor

.

Th

e

input

t

ermina

ls _

include

a

ground

con

nec

tio

n

for

the

cable

shield

and

the

transformer

input

windings

are

ungrou

nde

d

or

"floating"

.

This

the

possibility

of

setting

up

a

severe

ground-

Ioo.p and al

so

J:)2rm

it

s

one

side

of

the

transformer

i

nput

to be

grounded

for

single

-ended

operat

ion

if

desired.

In

like

manner

,

th

e

program

line

out

:lt1ts

are

al

so

isolated

.

A

central

ground

lug is

provided

on

the

r

ear

pan

el

for

connection

to

the

system

m

as

ter

ground,

and

as

heavy

a

guage

strap

or

braid

as

pract

ic

al

sh

ould

be

u

se

d.

www.SteamPoweredRadio.Com

CIRCUIT

DI:SCRIPTlON ,

SPARTA

AUDIO

CONSOLES

GENERAL .

The

description

to

fo

ll

ow

is

generally

applicable

to

all

SPART

A

consoles

, m

ono

or

stereo,

and

out

lin

es

the

b

as

ic

syst

em

of

selecting

,

mixing

and

amplifying

the

usu

a1

program-

sources

p

lus

th

e

me

th

ods

used

to

process

auxilliary

functions

such

as

cue

and

monit

or

signals.

Features

applicable

to

specific

consol

es

are

t

hen

discussed

elsewher

e

in

th

e

appropria

te

manu

al

section

s .

Microphon

e

Preamplifiers

.

With

a

nomina

l

gain

of

SSdb

.

the

output

l

eve

l from

the

preamp

to

the

mixer

potentiometer

is

ty

pically

-1

0

to

Jf

dbm

.

depending

,

of

course,

on

th

e

sound

l

eve

l

and

microphon

e

u

sed.

In a

norma

l s

ituation,

then

,

th

e

preamplifier

output

is

at

essentia

ll

y

the

same

l

eve

l

as

th

e

high-

l

evel

input

signals

,

resultin

g

in

approximate

ly

th

e

same

mixe

r-l

eve

l

settings

for

normal

operation

.

Pr

eamp

gain

can

be

changed

to

accommodat~

unusua

l

situations

by

ref

erring

to

the

preamplifier

circuit

description.

As

n

orma

lly

supplied

by

SPARTA

, t

he

·i

nput

tran

s

former

is

wired

for

u

se

with

150/

250

ohm

microphones

. A

transformer

tap

is _

provided

for

easy

conv

e

rsion

to

use

with

30/50

ohm

mi

cropho

n

es

.

All

SPARTA

Aud

io

Consoles

are

supplied

as

standard

with

a

microphone

preamplifier

in

th

e

firs

t

mixer

position

.

Th

e

preamplifiers

are

int

e

rch

ange

-

abl

e

with

high-

l

eve

l

input

cards

,

how

e

ver,

so

additional

microphone

l.

www.SteamPoweredRadio.Com

CIRCUIT DESCRIPTION, GENERAL

pre

amp

lifi

ers

may

be

inc

orporated

,

or

alternately

,

all

inputs

may

be

high

-

l

evel

.

High

-

Level

Inputs

are

brought

to

the

primar~es

of

input-i

so

l

ation

transform

ers

which

are

suitably

terminated

and

connected

directly

to

t

he

proper

l

111ix

er

potentiometers

.

The

primaries

are

floating

(unground

ed)

to a

ll

ov1

1 s

in

gle-ended

connection

and

also

to

nt

the

possibility

of

setting

up

undesired

ground-loops

or

common

-

mode

si

gnals

via

th

e

inp

ut

cables.

Mixing

ta

kes

place

by

feeding

the

output

of

each

mixer

pot

e

ntiometer

t

hrough

a

high-valu

e

series

resistor

(l0K

or

27K)

to

a

common

mixing

bus,

which

in

turn

l

eads

to

a

mixing

amp

lifi

er

.

Th

e

mixing

amplifier,

which

is

usually

lo

ca

ted

with

the

line

amplifier,

is

specifically

designed

to

have

a v

ery

l

ow

input

imp

eda

nce

,

typica

ll

y

100

ohms

.

Since

the

Mixer

feed

resistors

are

so

much

higher

in

value

,

the

mixer

amp

becom

es

a

"curr

en

t

sink"

and

responds

to

the

current

in

the

feed

resistors

,

which

in

turn

is

de

termined

by

the

voltage

available

from

th

e

Mix

er

pots

.

The

output

of

th

e

mixer

amp

,

then,

is

propoi;-tional

to

th

e

sum

of

th

e

currents

at

it

s

input.

2.

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CIRCUIT

DESCRIPTION

, GENERAL

Mixer

isolation

is

excellent

with

th

is

system

since

the

current

from

each

fe

ed

resistor

will

fol.low

the

easiest

path

- -

obvious

ly

into

the

mix

er

amp

rath

er

than

to

another

Mixer

pot.

Changing

one

mixer-pot

,

t

hen

,

will

have

relative

ly

littl

e

effect

upon

the

program

level

coming

from

another

mixer

-

pot.

There

is

obviously

a

significant

loss

of

program

power

in

the

mixer

feed

re.

sisters

,

but

th

e

power

l

eve

ls

are

so

low

that

it

is

a

simple

matter

to

recover

the

l

oss

in

th

e

mixer

amplifier.

Mixer

amp.

ga±n

is

set

to

restore

the

program

to

substanUally

the

same

level

as

originally

fed

to

the

mixer

pots

,

with

the

mixer-pots

at

their

usual

operating

positions

,

about

one

o'clock.

Since

a

"current"

mixer

operates

from

a

rel

a

tiv

e

ly

high

source

imp

eda

nce,

it

allows

the

use

of

high

i

mpedance

mixer-pots

. And

since

it

is

not

critical

of

t

he

precise

source

impedanc

e ,

thete

is

no

need

to

resort

to

the

bulk

and

cost

of

precision

ladder

attenuators

.

Output

of

the

mixer

system

is

t

hen

fed

to

the

Master

gain

control

at

essenti

a

lly

the

same

l

eve

l

as

the

origina

l

high

-l

eve

l

program

material.

To

t

est

the

entire

mixer

system

, a -

10

or~·

dbm

signul

is

provid

ed

at

a

high-l

evel

input

,

th

e

appropriate

mixer

pot

is

set

at

th

e

normal

operating

position

and

the

signa

l

is

viewed

or

measured

across

t

he

Master

guin

contro

l.

3,

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CIRC

UIT

DI:SCRIPrION

, GENERAL

The

Linc

Amplifier

provides

th

e

final

amplification

between

th

e

Master

gain

control

and

the

li

ne

output

terminals

.

It

must

therefore

recover

t

he

signa

l

oss

of

th

e

Master

gain

control

,

compensate

for

any

losses

in

matching

or

isolation

pads

,

and

provide

power

-gain

for

driving

the

output

li

ne

at

rat

ed

l

eve

l.

F

or

a

rated

output

of

8dbm

into

a

600

ohm

li

ne

at

zero

VU

,

several

factors

must

be

considered

: A

minimum

of

10

dbm

of

add

ition

al

gain

,

without

distortion,

mu

st

be

available

to

handle

program

peaks

(

headroom

).

Also

,

th

e

output

transformer

must

be

isolated

from

the

line

with

a

pad

,

typic

a

lly

4 ·

db

,

to

prevent

int

eract

i

on

with

line

reactances

. Fin

ally,

the

li

ne

amplifie

r

output

-

imp

e

dance

must

properly

match

th

e

lin

e t

ransformer

primary

so

the

output

te

rmin

als

a re a

tru

e

600

ohm

source.

The

lin

e

transformer

must

th

en

handle

a

nominal

l

evel

of

l

2dbm,

and

22

dbm

on

program

peaks

.

The

lin

e

amplifier

must

be

capable

of

supplying

18dbm

to

th

e

line

plus

the

power

-l

osses

in

the

li

ne

pad

,

insertion

loss

in

the

t

ransform

er

and

internal

l

oss

necessary

to

obtai

n a

proper

imp

edance

match

.

This

is

considered

in

detail

in

the

line-amplifier

section

of

the

manua

l.

VU

Meter

.

The

standard

VU

m

eter

contains

rectifier

diodes

and

consequently

appears

as

a

non

-

lin

ear

imp

edance

to

its

signal

source

.

To

avoid

introducin

g

4.

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CIRCUIT DESCRIPTION , GENEHAL

dist

ortion

on

th

e p

rog

r

am

-lin

e ,

it

is

necessary

to

provide

isolation

be

tw

ee

n

th

e

meter

and

th

e

line.

It

is

a l

so

n

ecessar

y

to

a ttenw::ite

the

l

evel

to

the

mete

r

so

it

can

indic

ate

~

vu

when

the

line

is

a t

8dbm

and

finally,

the

attenuator

must

be

so

desig

ned

as

to

appear

to

the

meter

as

a 3 .

9K

ohm

source

to

p

reserve

th

e

.

lin

earity

of

th

e

me

ter

in

dication

.

This

l

atter

requirem

e

nt

accounts

for

the

meter

p

ad

being

a

"T"

configuration

r

ather

th

an

a

simple

se

ri

es

r

esistor

.

In

SPARTA

consoles,

th

e

metering

source

is

th

e

lin

e

transformer

output,

ah

ea

d

of

thG

line

pad

,

which

al.lows

an

added

4

db

of

attenuation

in

the

met

er

pad

for

increased

i

sola

t

ion.

A

balanced

"H"

pad

is

not

required

since

t

he

met

er

n

eed

not

be

ba

l

anced

to

ground.

Cu

e .

Common

to

a

ll

SPARTA

consoles

is

a "

Cue"

position

on

each

Mixer

pot

entiome

t

er.

In t

he

simpl

es

t

case,

program

materi

ol

from

each

mixer

,

thr

ough

th

e

cue

switches

and

isolat

i

on

resistor's

, i s

delivered

t o a

rear

- pa

nel

te

rm

ainal

for

feed

to a n e

xt

erna

l

cue

amplifjer

.

In

more

elaborate

consoles

, a

cue

l

eve

l

control,

i

nterna

l

ampli.fier

and

optional-u

se

internal

speaker

are

.

p

rovid

ed .

Monitor.

Although

provis

ion

s

for

program-line

monitoring

vary

in

different

SP

ARTA

conso

l

es

,

in

a

ll

cases

th

e

source

of

program

mc1

t

erial

is

th

e

output

5.

Sparta AS -30B User manual

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