Hafler 0915P manual Volume Control Balance Control

TAPE INPUT/ RECORD OUTPUT

TONE CONTROLS/ TONE SWITCH

VOLUME

CONTROL

BALANCE

CONTROL

The 915 incorporates one monitoring loop for use with tape decks, or other input/output signal processors.

The Ret Out	jack	feeds a signal to a	tape recorder’s input. The signal present at this output			is
the same as indicated by the Selector			Switch. This output may alternately	be used	to feed	the
input of a signal processing device, such as an equalizer.
Though rare,	it is	possible that some	external devices connected to Rec	Out may	cause	slight

distortion to the main signal path when that device is turned off. This is due to possible

semiconductor junction rectification in unpowered

circuits.

If

this

is

suspected,

leave

power

applied

to

any device connected to Rec

Out

during

critical

listening.

The Tape Input is electrically the same as the other line level inputs,

but

is

selected via

the Tape

Monitor Switch. Activating this switch (UP

position)

breaks

the

main

signal

path

after

the

Input

Selector System and allows monitoring of

the tape decks output, during recording or playback.

Activating

this switch does not affect the signal

at

the

Rec

Out

jacks.

The Tape

Input may alternately be

used for

the return signal from a

signal

processing device,

such

as an equalizer. The Tape Input may also

be used for an additional

line level

input,

although

this

signal

cannot be made

available to the Rec

Out

jacks.

A common system “malfunction” can often

be

traced

to

inadvertently

leaving

the

Tape

Monitor

Switch engaged: in case of no sound from

a

selected

line

level

input,

check

that

the

Tape

Monitor

Switch

is

de-activated

(DOWN

position).

See the Functional Block Diagram for a better understanding of the Tape Monitor Signal routing.

The

Tone In Switch activates the Bass

and Treble Controls when moved

to

the

UP position.

I n

the

DOWN position,

the

Tone

Controls

are completely removed

from

the

signal

path,

regardless

of Bass and Treble knob

position.

The

Bass Control has a variable inflection, or

“hinge” point so that only the very low frequencies

are

affected by small amounts of knob rotation on either side

of

center.

This

facilitates

small

amounts of low frequency corrections

without

noticeably

altering

the

musical

balance

at

upper

bass frequencies. As the knob rotation

is increased further from center,

frequencies closer to 500

Hz

are

affected.

The

Treble Control has a fixed “hinge” point at

1 kHz and has a “shelving” action above 5 kHz.

This

affords proper high frequency corrections without irritation from excessive boost at extreme

high

frequencies.

Activating the Tone Control Switch may

cause a slight change in tonal balance even when both

Bass and Treble controls are in their

center

detented

position,

and therefore the Tone System

should be disabled via the switch when

no tone control action is

desired.

The

tone controls

also

limit

the

total bandpass

of

the

line amplifier.

This precision detented

potentiometer increases output level in approximately 1 dB steps

clockwise

from

the

12

o’clock

position.

Counterclockwise

from

the

12

o’clock

position,

each

step

is progressively

greater

until

full

attenuation

is achieved at maximum counterclockwise position.

This

arrangement allows the most natural and

useful volume

control

action

for

a

wide

variety

of

listening

levels.

This control alters the proportion between right and left output volumes. In the full counterclockwise position, only the left channel will be heard. In the full clockwise position, only the right channel will be heard. The Balance Control is useful for balancing the acoustic output of the system between left and right speakers, as well as being useful for system troubleshooting.

-9-