Dyna FM-3 - Dynaco FM-3 Introduction and Operation; Dynatuner Overview and Design Philosophy; Operation of Controls and Indicators

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THE

FM·3

DYNATUNER

Your

FM-3

Dynatuner

is

one

of

the

most

thoroughly

researched

and

field

tested

components

in

the

h.igh fidelity

industry.

More

than

four

years

of

engineering

effort

have

been

devoted

to this

one

design

with

two specific goals

in

mind:

one,

performance

which

cannot

be

improved

at

the

present

state

of

the

art;

two,

assurance

that

this

perform-

ance

level

can

be

achieved

and

maintained

by

the

user

in

the

home.

Side-by-side

listening

comparisons

of

the

Dynatuner

with

tuners

several

times

its

cost

demonstrate

the

great

extent

to which

these

goals

have

been

aChieved.

Published

specifications

cannot

define

the

clear

superiority

of

the

Dynatuner

in

low

distortion

reception

of

both

very

weak

and

exceedingly

powerful signals,

its

remarkable

freedom

from

the

problems

of

cross-modulation

and

severe multi-

path

effects, its high

order

of

suppression

of

impulse-type

interference,

its

exceptional

capacity

to

handle

severely

overmodulated

signals

without

distortion,

and

its

unique

ability

to

maintain

full

stereo

separation

with

the

weakest

signals.

These

comparisons

can

be

demonstrated

using

Dyna-

tuners

built

and

aligned

by

novice

constructors,

and

it

is

this

that

represents

a

fundamental

difference from

other

designs.

The

Dynatuner

is a

fresh

engineering

concept,

not

an

adaptation

of

an

existing

production

unit.

Every

portion

of

the

circuit

has

been

carefully

investigated

in

terms

both

of

performance

maxima

and

of

the

overall

stability

of

operation

and

simplicity

of

adjustment

required

of a

kit

design.

The

net

result

significantly

surpasses

on

all

counts

units

which

require

that

certain

sections

be

pre-built

and

aligned,

and

which

are

therefore

incapable

of

complete

home

alignment.

The

Dynatuner

provides

the

same

top

performance

in

your

home

as

in

the

laboratory,

as

it

can

always

be

properly

aligned

using

the

unique

procedure

detailed

later

in

this

manual.

This

ability

to

be

aligned

without

test

equipment,

with

an

alignment

as

accurate

as

can

be

per-

formed in

the

laboratory,

means

that

aiter

shipping,

after

aging,

after

tube

replacement,

or

after

any

other

cause

for

change

in

alignment,

the

unit

can

be

restored

to

peak

performance.

In

addition

to

the

adjustment

requirements,

the

basic

engineering

objective

was

to

produce

a

tuner

with

sufficient

sensitivity

for fringe

area

reception,

with

distortion

levels

of

the

recovered

audio

signal

comparable

to

that

measured

on

the

best

of

audio

amplifiers.

The

concentration

of effort

to

reduce

distortion

of

all

types

has

produced

a

tuner

which

is

unquestionably

one

of

the

very lowest

distortion

tuners

available

at

any

price.

The

significant

advantages

of

etched

circuit

construction

in

terms

of reliability,

reproducibility

and

durability

are

amply

demonstrated

in

the

Dynatuner.

Their

use

has

further

accomplished

the

ultimate

goal

of

improved

per-

formance.

In

no

other

tuner-kit

or

factory

wired-bas

exact

component

placement

and

lead

layout

been

so

ac-

curately

defined.

Tbe

excellent

specifications

of

the

Dyna-

tuners

are

possible,

and

guaranteeable,

unit

to

unit,

lab

model

to

production

kit,

because

of

tbe

extraordinary

uni-

formity

which

etched

circuits

provide,

and

the

inherent

stability

of

the

circuit

configuration.

There

has

been

no

intent

to

enter

the

s2nsitivity

speci-

fication

race

(claims

often

engineered

by

the

advertising

department).

However,

using

the

sensitivity

standards

pro-

posed

by

the

Institute

of

High

Fidelity,

this

tuner

belongs

in

the

highly

sensitive

class

and,

in

fact, will

provide

listenable

reception

of

more

stations

than

tuners

of osten-

sibly

higher

sensitivity

rating.

There

are

many

parameters

in

addition

to

sensitivity

and

distortion

which

are

part

of a

completely

satisfactory

tuner

design.

Some

are

measurable;

some

are

intangible.

The

design

requirements

for a

premium

quality

kit

lead

automatically

to a

distinctly

superior

factory

assembled

tuner

as

well.

Extensive

field

testing

under

adverse

and

marginal

conditions

has

proven

the

Dynatuner

to be

as

fine a

tuner

as

can

be

obtained

today

regardless

of

price

or

specification claims.

Operation

of

'he

Controls

Operation

of

your

FM-3

is

remarkably

simple.

Its

highly

refined

engineering

combines

the

performance

of

far

more

costly

and

complex

FM

tuners

with

the

operating

ease

which

has

become a

Dyna

hallmark.

The

elimination

of

front

panel

adjustments

and

controls

is possible

only

through

exhaustive

engineering

research

to

accomplish

their

objectives

by

automation,

freeing

the

listener

to

enjoy

exceptional

FM

reception.

The

function

of

the

power

switch

is

obvious.

This

switcb

also

controls

the

AC

outlet

on

the

rear

of

the

tuner

so

that

it

is

possible,

if

desired,

to

turn

both

tuner

and

amplifier,

for

example.

on

and

off

simultaneously

if

no

preamplifier

is used.

It

is

also

possible

when

using

the

Dynatuner

with

equipment

which

has

additional

switching

facility,

such

as

the

Dyna

PAS

preamplifiers

or

SCA-35

amplifier, to

leave

the

Dynatuner

power

switch

"ON",

and

use

the

amplifier

for

all

switching,

The

tuning

knob

is

used

to

select

stations.

When

the

station

is

correctly

tuned,

the

lower

tuning

eye

will close

to its

maximum.

Always

tune

a station while watching the

tuning

eye,

rather

than

trying

to

set

to

a precise

frequency

on

the

tuning

dial.

The

eye

is

designed

so

that

it

will

never

overlap,

but

at

any

signal

strength,

there will be a single

point

of

correct tuning.

At

this

point

you

will receive

the

station

with

lowest

distortion,

maximum

noise

rejection

and

maximum

separation

of a

stcreo

signal.

The

tuning

eye

will

indicate

maximum

closure

with

a

signal

strength

below 20

fLv,

yet

higher

signal

strengths

will

not

overlap

it.

The

precise

center

of

channel

is

always

apparent-there

is

no

"flat

spot".

It

will

indicate

signals

as

weak

as

1

fLv,

but

these

signals

are

likely

to

fluctuate

widcly.

Normal

center

channel

indication

may

be

anywhere

between

lit

division

and

3 divisions

gap

on

the

reference

grid,

depending

on

the

particular

tuner,

and

signal

strength.

Once

a

station

is

tuned,

the

upper

beam,

or

STEREOCATOR,

will

indicate

immediately

whether

or

not

the

broadcast

is

in

stereo.

Betwecn

stations

the

STEREOCATOH

may

light

or

flicker.

There

can

be

no

confusion

as

to

whether

or

not

you

are

listening

to

a

stereo

broadcast

if

you

tune

for closure

of

the

lower

tuning

eye

first,

and

then

observe

whether

or

not

STEREO

is

lighted

above

it.

The

STEREOCATOR

operates

from

the

19KC

pilot

signal

which

is

an

integral

part

of

all

stereo

broadcasts.

Occa-

sionally

there

may

be

instances

where

a

station

neglects

to

tum

off

this

19KC

pilot

when

it

reverts

to

monophonic

programming,

and

this

will give

you

an

erroneous

STEREO

indication.

Noise

on

extremely

weak

signals

(there

is

some

19KC

in

random

noise)

and

also

19KC

harmonics

in

tbe

program

material

may

cause

some flickering

of

the

3

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