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DYNACO Stereo 70 Instructies voor montage

smooth transition of sound between the speakers.

not correct, there will be an intermediate

area where the sound will shift -from one to the

other.

phasing is not correct, it can be rectified

by interchanging the two leads between one of the

amplifier c h ann e I s and its associated speaker.

There should be no need to change phasing once

the system is set up properly.

Proper phasing

the stereo pickup or tape

head is generally accomplished by the manufac-

turer of this item. However, this can be inverted in

installation if directions are not followed precisely.

there is a drop in volume using a monophonic

tape or disc, this indicates probable incorrect

phasing.

interchange of ground and "hot" side

of one of the cartridge channels or of the two leads

to one channel of the tape head will remedy this

type of incorrect phasing.

Hum is another problem which the stereo disc

playback cartridge can introduce.

some cases

(particularly where independent preamps are used

for the two channels) the use of a common ground

lead on the two inputs will provoke a hum condi-

tion. For this reason, many stereo pickup manu-

facturers provide separate ground connections for

each channel by using four cartridge terminals.

The cable shields of the two channels should be

kept separated.

a three terminal magnetic cartridge arrange-

ment is used, it is very possible that hum will be

encountered if the equipment from the two channels

has any additional interchannel connection (beside

the common shield from the pickup). Connection

of the Stereo 70 should not give this trouble. How-

ever, dissimilar units in each channel can be a

source of hum when three terminal cartridges are

used.

Crystal and ceramic cartridges which go

into high level inputs should not normally introduce

this type of hum problem.

Positioning of loudspeakers will af fee t the

quality of stereophonic reproduction.

Generally,

moderate distances of six to ten feet along the

same wall pro vi d e the best effect.

greater

spacing is required, the use of a blend control can

help to provide "fill" in the middle. However, if

extreme distance is required, a "phantom" middle

channel is useful.

has generally been established

that an L

R combination of the two channels pro-

vides the best center fill. Information on the proper

method for obtaining this signal, using either the

two regular stereo amplifiers, or a third ampli-

fieI', may be obtained on request from Dynaco,

Inc. This arrangement will also provide a com-

bined signal for a remote monophonic extension

speaker.

In most rooms, the proper balance of the

stereo system will be different for different listen-

ing positions.

the listening positions are rela-

tively far from the s pea k e

s, this problem is

diminished, and' optimum results are obtainable

for several listening positions simultaneously.

The most basic consideration of the installation

and use of a stereophonic system is that stereo

alone does not create realism and high quality

sound.

Two low grade stereo channels will not

give the qua 1it

of one high grade monophonic

channel.

There is no substitute for high quality

components, carefully installed.

IN CASE OF TROUBLE

Your Dynakit Stereo 70 has been designed to be

as free from trouble as possible.

However, a

mistake in assembly or a defective component can

affect its performance or m a k e it inoperative.

Some trouble-shooting procedures are suggested

in case difficulty is encountered.

Naturally the

wiring should be checked very carefully to make

sure that all con nee t ion s have been made in

accordance with instructions.

The tubes should light after a few seconds of

warmup.

they do not, it is probable that there

is no ac voltage getting into the amplifier, which

indicates a possible blown fuse.

Fuse failure

If fuses blow frequently without apparent cause,

this may sometimes be rectified by using a slow

blow type of fuse. However, do not exceed the 3

ampere fuse rating when replacing fuses.

fuses blow within 30 seconds of turning the

amplifier on, remove the GZ -34 rectifier tube and

see if this cures the problem.

it does, the

rectifier may be bad and another should be tried.

A 5U4GB type of rectifier can be substituted for

trial purposes, although using this tube type will

cut down the maximum power rating of the ampli-

fieI'.

the GZ -34 is not at fault, the quadruple

section filter capacitor may be snorted. Generally,

shorts in this section of the amplifier will show up

in a measurement of resistance (with the amplifier

unplugged from the 117 volt line) from capacitor

to ground. This resistance should exceed 100,000

ohms.

Fuses blowing with all tubes removed indicate

either m i s wi

in g or a defective P A-060 power

transformer.

Tubes glowing

one (or a pair) of the EL-34's glows a bright

red color after slight warmup, it is possible that

the tube is bad, or there may be a fault in the bias

supply which supplies neg at i v e voltage to the

EL-34' s, measurable (with a high impedance meter

such as a VTVM) at pin #5 of each EL-34. The