Fostex 250 - Page 10

this instance). The object at this point is to record on only
one track ot the tape at a time. If the PAN pot is set in
some mid position, part of the signal is being assigned to
an unused buss, which serves only to degrade the signal -
to-noise ratio on the track being recorded (part of the
signal is "wasted”). In some cases it is possible one
could hear a signal in the headphones (or monitor
speakers), even though that signal is not actually being
recorded.
8. Set the METER function switch to RECORDER position so
that VU METER # 4 will monitor the signal level from input
channel 1 (as assigned to record buss # 4).
NOTE: In order to adjust the TRIM (LINE-MtC) control, it
will be necessary to provide an average level signal at the
channel input. It is O.K. for you to sing, talk, or play an in¬
strument, although during setup it will be easier to have a
friend do this as you adjust the Model 250 controls. Alter¬
natively, use a radio, phonograph record played over
speakers, a continuous organ note, or any convenient
sound that will stimulate a microphone at approximately
the level of the ultimate sound source. After the setup is
achieved and the actual performance is under way, the
levels can be retrimmed slightly, as may be required.
9. Begin with the TRIM control set fully CCW at LINE posi¬
tion. Then with a typical signal present at the channel in¬
put, adjust the trim control until the METER pointer peaks
at from - 3 VU to 0 VU (The TRK 4 meter in this example).
The peak indicating LED in the meter face should flash
only occasionally, if at all. Do not record at too low a level
(e.g., -20 VU), as this will cause excess noise. If the
peak LED flashes regularly with the VU meter topping at
-3 to 0 VU, the sound source has a very high peak-to-
average signal ratio (e.g., forte piano or plucked guitar).
To avoid distortion, readjust the trim to reduce LED
flashing, and accept the somewhat lower average VU
level. (It may be desirable to use a compressor.)
NOTE: The system is now adjusted for proper signal
levels from the channel input, through the record elec¬
tronics, and onto the tape. It is now appropriate to set up
the monitor section; adjustments of HEADPHONE level
do not affect the recording or VU levels.
10. The MONMIX knob is set at #7. This knob is located at
the top of channel 4; the other MONMIX knobs are set full
CCW.
NOTE: Observe that the MONMIX controls associated
with channel 4 are used, not channel 1. This is because
the recording is occuring on track 4. Any one or more in¬
put channels can be assigned to track 4 (channel 1 was
used here), but the playback from track 4 is accessible
only by means of the MONMIX control of the channel
numbered to correspond to the track (e.g., #4).
11. Initially set the HEADPHONE control at center (OFF), and
plug a pair of 8-ohm or'higher impedance stereo head¬
phones into either HEADPHONE jack on the Model 250
front panel; then advance the knob CCW to obtain a com¬
fortable listening level.
NOTE: Assuming that the AUX INPUT jacks are not being
used during this operation, it is a good idea to set RCV1 -2
at minimum (HO) to eliminate any hiss from the unused
inputs.
12. There is another method to HEADPHONE monitoring for
obtaining the most pleasing sound by passing the
playback signal through the equalizer.
The INPUT selector of channel 4 is set to TAPE position.
The INPUT fader is set at nominal position, PAN pot at
center, the 4 CHAN BUSS at 3-4 position (not at 1 -2 posi¬
tion as it will oscillate), the MASTER 1 -2 fader at nominal
position, and the HEADPHONE control is gradually ad¬
vanced CW from its OFF position until the 4 CHAN BUSS
signal is heard at a comfortable level.
13. Press the RESET button to zero the index counter so that
after the recording, the ZERO RETURN button can be
used to automatically rewind to this point on the tape.
14. Check the PITCH CONTROL to make sure it is centered
so that tape records at normal 3-3/4 ips speed (9.5 cm/s).
NOTE: Recording can be done at faster or slower speeds
for certain special effects, but for “normal" recording
PITCH should be centered.
15. When ready to begin recording, simultaneously depress
the RECORD and PLAY buttons. Confirm that tape is win¬
ding at constant speed onto the right hub. The LED above
the # 4 RECORD TRACK button now should stay on in¬
stead of blinking, and the record mode LED adjacent to
the RECORD button should also turn on.
NOTE: Check the VU METER and peak LED occasionally
to ensure they are in the proper range. If level ad¬
justments are necessary while recording, USE THE IN¬
PUT FADER, NOT THE TRIM control.
16. When the recording is completed, press the STOP button
(which cancels recording and stops the tape).
PLAYING BACK THE INITIAL TRACK JUST RECORDED
Figure 3. Steps for playback of the initial track.
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