Hafler 945 Stereo Amplifier User Manual


 
TAPE INPUTS
and TAPE
OUTPUTS
The 945 incorporates two Tape Loops for use with audio tape decks or other input/output signal
processors. Due to the great flexibility of connection and control, the Tape Loops are probably the most
complicated portion of the 945 to understand and operate. Therefore, a thorough reading of this section
is strongly recommended. Consultation of the Functional Block Diagram will aid in understanding the
signal flow inside the unit.
TAPE DECK CONNECTIONS: The Tape Inputs are electrically the same as the other line level inputs,
but are selected via the Tape Monitor 1 and 2 buttons. Activating these switches (red light ON) breaks
the main signal path after the Input Selector buttons and allows monitoring of a tape deck’s output, during
recording or playback.
The Tape Outputs feed an audio signal to a tape recorder’s input. The signal present at Tape 1 Out is
the same as indicated by the Input Selector buttons. The signal present at Tape 2 Out is also the same
as indicated by the Input Selector buttons, unless Tape 1 is selected. Under this condition, the signal
present at Tape 2 Out is the same as Tape 1 Input. This arrangement allows dubbing from Tape 1 to
Tape 2.
If only one tape deck is connected to the system, Tape 2 is the preferred input. This allows the Tape
1 input to be used as an additional line level input. If two tape decks are connected to the system, and
tape copying is to be performed, connect the
"source" deck
to Tape 1, and the
"destination" deck
to Tape
2.
SIGNAL PROCESSOR CONNECTIONS: The Tape Loops may also be used for connection of signal
processors (such as equalizers, etc.). The Tape Outputs are used to send the signal to the processor,
and the Tape Inputs are used to return the signal from the processor.
If only one signal processor is connected to the system (and no tape deck), Tape 2 is the preferred loop.
This allows Tape 1 to be used as an additional line level input. If one signal processor and one tape deck
is connected to the system, it is usually preferred to connect the processor to Tape 2, and the tape deck
to Tape 1. This will prevent the processor from affecting signals sent to the tape deck. If it is desired
to affect signals sent to the tape deck, then connect the devices in the opposite order. If two signal
processors are connected to the system, then a decision must be made as to which device should come
first in the signal path. This will depend on the type of device connected and the effect desired.
NOTE: Though rare, it is possible that some external devices connected to the Tape Outputs 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 the Tape Outputs during critical listening.
A common system “malfunction” can often be traced to inadvertently leaving a Tape Monitor button(s)
engaged (red light ON). In case of no sound from a selected line level input, check that the Tape Monitor
button(s) is in the de-activated position (red light OFF).
TONE CONTROLS
and TONE IN/OUT
The Tone In/Out button (on the Front Panel or via the Remote Control) activates the Bass and Treble
Controls when the button is lighted green. In the OUT mode (button light is off), the Tone Controls are
completely removed from the signal path, regardless of Bass and Treble knob position.
Control of Bass and Treble is not available via the Remote Control, although preset tone settings may
be enabled via the Remote Control Tone In/Out button.
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.
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