Korg POLY-61 - EG Checks

(2) I n crease oscilloscope range and observe enlarged
ringing section. Adjust VR103~603 (VR101~601
(fc ADJ)) to obtain cycle of 2.0msec, as shown in
FIG-11.
Fig-11
(3) S et to PROGRAM 41; play C6 and confirm Fig-12
waveform.
Fig-12
(4) Change oscilloscope range to enlarge ringing and
confirm ringing cycle of 20~4Ctytsec. Variation
between 6 voices should be within 10/zsec.
(5) Set to PROGRAM 42, play Cl, and gradually
reduce PARAMETER 31 (CUTOFF). Confirm that
the waveform's ringing cycle gradually becomes
longer and that it virtually becomes a sine wave
at about CUTOFF=14. Also confirm that maximum
level is reached at a CUTOFF VALUE of 10~18
and that it is 6Vp-p or less. (Deviation between 6
voices should be within three CUTOFF VALUE
steps and no more than IV.)
3) KBD TRACK.
(1) Set to PROGRAM 43 and play Cl, C3 and C6.
Confirm that amount of ringing for any key (not
just Cl, C3, C6) is 2.5~4 (average of 3) for all
6 voices. (C6 is a bit less and Cl is a bit more.)
(2) Find key that produces least change in fc (change in
ringing cycle) when PARAMETER 33 (KBD
TRACK) is switched between 1 (ON) and 2 (OFF).
Confirm that key is between B2 and F3 for all
6 voices.
4) EG INTENSITY.
(1) Set to PROGRAM 44 and play C6. Confirm rectan¬
gle waveform with ordinary ringing for 6 voices,
then change oscilloscope TIME/DIV and measure
ringing cycle.
(2) Change program from 44 to 45, 46, 47, 48, 51, 52,
in order, and confirm that ringing cycle is within
20'~40Atsec. Deviation between 6 voices should be
no more than 15/tsec. It is still acceptable if the
above specifications can be achieved by changing
PARAMETER 31 (CUTOFF) VALUE by ±1.
5. EG.
1) EG MODE.
(1) Set to PROGRAM 53, play any key and confirm
that there is no abnormality in ADSR for all 6
voices.
(2) Confirm that changing PARAMETER 51 (EG
MODE) from 1 to 0 gives an organ tone for all
6 voices.
2) ATTACK.
(1) Set to PROGRAM 54 and play C6.
(2) Confirm that ATTACK TIME is.350msec (±20msec)
for 6 voices. Adjust VR102~602 (VR104~604) if
necessary.
*NOTE: Adjust oscilloscope (TRIG MODE at
NORMAL; adjust TRIG LEVEL) to obtain sharpest
envelope attack.
(3) Set to PROGRAM 55. Confirm ATTACK TIME
(maximum value) of 8~12sec and deviation be¬
tween voices of within 2sec.
3) DECAY.
Set to PROGRAM 56. Confirm DECAY TIME
of 15'“30sec and within 7sec deviation between 6
voices.
*NOTE: Here DECAY TIME is the time from when
you play a single key to when you can no longer
hear the sound from the amp. At the same time
confirm that sustain level does not remain.
4) SUSTAIN.
Change PROGRAM from 57 to 58, 61, 62 and
confirm that SUSTAIN LEVEL gradually rises for
all 6 voices.
* NOTE: At PROGRAM 57 (SUSTAIN = 1), the
sound is barely audible when amp volume is turned
up, although it may not be heard at all. A short
"pop" sound is not abnormal since ATTACK and
DECAY are both at 0.
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