Crosstalk Between Channeis - Teac TASCAM 388 STUDIO 8 Operation & Maintenance Manual

5) Compare the output leveis obtained ¡n the
steps 2 and 4; the level difference should be
higher than 70 dB for each channel.
6) If not:
* Olean the tape transport path.
*Check the tape transport mechanism.
OSOLUOSCOPE
OSCILLATOR
AMP SPKR
AC VOLTMETER
FlUTER
ATTENUATOR
UNIT
under TEST
Fig. 1-5-5. Erase Ratio Test Set-Up
1-5-10. Crosstalk Between Channeis
1)Set and adjust the test equipment as men-
tioned under "1-5-6. Overa!! Frequency
Response".
2) Record the reference signa! of 1 kHz, -10 dB
(0.3 V) on the channe! 1. Rewind the tape
just recordad and reproduce it. Measure the
leakage output leveis to the adjacent channeis
through a 1 kHz füter, and measure ratio(s)
against the reference leve!.
3) The ratio should be higher than 55dB for
each channe!.
OSOLUOSCOPE
AMP SPKR
AC VOLTMETER
CH?
ATTENUATOR CH? FILTER
UNIT
under TEST
Fig. 1-5-6. Crosstalk Measurement Set-Up
1-5-11. Syno Crosstalk
This refers to the crosstalk between adjacent
tracks when a SYNC recording is made. !n other
words, it refers to the degree of leakage into an
adjacent track of a bias signa! from a recording
track.
Measurement setting is made in the same manner
as mentioned under "1-5-6. Overa!! Frequency
Response".
The foüowing procedure should be repeated for
al! pairs of tracks listad in tables.
Crosstalk between Track #1 and #2
1) Place the TRK#1 REO FUNCTION switch
in the "ON" position.
2)App!y 15 kHz, -10 dB (0.3 V) reference
signa! to PGM BUSS IN jacks. Set the deck
to RECORD mode.
3) Check how much of the signa! applied to the
track #1 leaks into the track #2, and read
the leve! difference against the reference
leve!.
4) Adjust R507 for minimum reading.
5) Repeat adjustment for al! other combinations
of tracks by referring to the table below.
RECORD
Track
REPRO. Track
(TAPE GUTCh.)
Adj. Pot
(REC/PLAY PCB)
1 2
R507 (Ch 1,3 PCB)
2
3
R507 (Ch 2, 4 PCB)
3 4
R607 (Ch 1,3 PCB)
4 5
R607 (Ch 2, 4 PCB)
5 6
R507 (Ch 5, 7 PCB)
6
7
R507 (Ch 6, 8 PCB)
7 8
R607 (Ch 5, 7 PCB)
8 7
R608 (Ch 6, 8 PCB)
7 6
R608 (Ch 5, 7 PCB)
6 5
R508 (Ch 6, 8 PCB)
5 4
R508 (Ch 5, 7 PCB)
4 3
R608 (Ch 2, 4 PCB)
3
2
R608 (Ch 1,3 PCB)
2
1
R508 (Ch 2, 4 PCB)
*R508 (Ch. 1, 3 PCB) and R607 (Oh. 6, 8 PCB)
are not used.
Crosstalk between Track #1 and #3
Put track #1 into record mode and, while
watching the leve! at TAPE OUT #3, adjust
R101 so that leakage into track #3 becomes
minimum. Repeat adjustment for al! other com
binations of tracks by referring to the table
below.
RECORD Track
REPRO. Track
(TAPE OUT Ch.)
Adj. Pot
1
3 R101
2 4
R102
3 5 R203
4
6 R204
5
7 R205
6 8 R206
8 6 R208
7 5 R207
6 4 R106
5 3 R105
4 2 R104
3 1
R103
1 25