OPERATION
Turn on:
Because of the delayed warm up characteristics of vacuum tube equipment,
a time delay muting circuit is incorporated in this preamplifier. Output 1 and Output
2 are grounded via a relay for approximately 45 seconds after the unit is turned on in
order to suppress warm up transient noises. The relay grounds the outputs again
immediately at turn off or in the event of any power line interruption.
Selector:
Use the selector switch to.choose an input from Phono, Tuner, Tape l, Tape
2 or Auxiliary inputs. The selected source will be available at the source (out)
position of the tape monitor switch and at both Record Outputs. Note that dubbing
between tape decks is possible in both directions. Also, since the selected decks'
output is fed back to its own record input, care must be taken not to select a tape deck
which is in the record mode. Similarly, if one of the tape loops is used for an external
signal processor, that tape loop should never be selected (and, of course, there is no
reason to select it since the external processor is not itself a program source). Failure
to observe these precautions will create an unstable feedback system and may
generate a "howling" sound.
Monitor:
This switch permits you to compare source and tape while recording on
either or both tape decks from the selected input. You may wish to use Tape 2 and
Record 2 to install an external signal processor such as graphic tone controls. Then,
the Tape 2 position will choose the processed signal while Source will choose the
pure signal.
Balance:
Permits continous control of location of stereo image from left to right. In
the full counterclockwise position only the left channel will be heard. Similarly, the
full clockwise position will reproduce only the right channel. In normal use this
control will be centered.
Volume:
The PV7 volume control Is an extremely precise control, maintaining
channel to channel tracking within t 1/2 db throughout its rotation.
