Testing & Development Log July 2015

Testing in standalone doepfer mini case.

Seq output looks cleaner than Pressure Points

Noise Generator

R32 is 1k Minimum trimmer setting: Attenuates to zero

Maximum: Absolute peaks after a couple of minutes
+9.84v
-9.52v
Average: 1mv

Calibrate:
Clock at 1khz, 16 steps
Main knob positions:
Extreme CW and CCW = no audible changes for 1m
3pm and 1pm = 10-30 changes in 1 minute
Noon = white noise
NB: Smooth transition between solid tone and white noise
Noise output after calibration:
Absolute peaks after 1 minute:
+10.1v
-9.52v
Average + 5.12
Average - 5.02
Overall average 22.5mv

IDEA: It's operating close to limits of op amps. Reduce voltages at comparator, to make it all more stable.
ie: Reduce R6 to reduce the overall CV input levels
Simulation: Reduce R6 to 50k, voltage from knob swings between -4 to +4
Test circuit simulation

R6 changed to 47K
Recalibrate as above
Noise output after calibration:
Absolute peaks after 1 minute: +3.4v
-2.92v
Average 2.17
Average -2.06
Overall average 6.57mv
= Approved

IDEA: R32 should go back up a little, to enhance range of trimmer use.
FOR: Makes trimmer/calibration easier
AGAINST: What if a weak noise transistor can't be boosted enough? = Rejected

IDEA: Move R16 and C4 from
between IC2A pin 2 and the switch
to between IC5B 10 / IC5A 2 and R17 Q: Is R17 Necessary? Q: If R17 is removed, can R18 become 10k? Test:

• Remove C4
• Short Circuit R16
• Now IC2A pin 2 is connected to STEP_16
• Replace R17 with 10k (You've now removed R17 from it's original role)
• Add 1n capacitor BETWEEN R18 leg closest to Trimmer AND ground - the closest pad on the switch. = Tested and working.

IDEA: In PCB layout, isolate power supply to Noise Generator

IDEA: Replace 2 x transistors by using spare 4016 switches as inverters Test 1:

• Remove T2 (left hand side / lower) DONE
• Connect right hand side of R24 to Pin 8 of 4016 done
• Connect pin 9 to GND
• Lift Pin 6 from socket and connect to right hand side of R25
• TEST - WORKS
• If it works, Short R25 - may be unnecessary
• TEST - WORKS

Test 2:

• Remove T3 (upper)
• don't need to physically Remove R4
• Lift pin 5
• Connect 4016 pin 1 to pin 5
• Connect pin 3 to GND
• Connect pin 4 to pin 11

IDEA: Add current limiting resistors to end of clock comparator and control comparators to reduce overall current use & heat generation??
heat is around ic6 and 4016
lifting pin 7 on IC6 = heat goes away
hard to measure current on my multimeter
TEST: 100k between pin 7 and pin 6 on 4016
RESULT: Heat is gone, needs full functional testing. Module power consumption falls to 56mA +12v

Other two op amps still warm

---

Panel building

Shift to bottom connector

start of loop
end of loop back
loop ctrl back
step_12_back
step 16 back
+create NOISE_BACK

• move CV combining IC to back

Radio Music
PCB height = 107 mm
LED position 4140 mils
bottom row sockets = 250 mils
second row sockets = 825 mils

Power header 1300 975 1 bottom right
Bus 1 3750 975 1 bottom right
Bus 2 1300 1775 1 bottom left
mounting hole top 950 1800
mounting hole bottom 3750 150

Radio Music PANEL Height 128.5 width 20 Bottom Screw holes: 3 12.5 = 7.5 from edge Bottom Sockets: 17.1 up Top LEDs 115.906 top screw holes 125.5

Turing Panel Should be 128.5 x 50.50

Positions before shifting into place: width 49.5 = move everything up 0.5mm to centre horizontally = MOVE (>0 0) (0 .5);

Bottom sockets 6.35 up - should be 17.1 = move 10.75 up Top LEDs 105.156 up - should be 115.906 = move 10.75 up = MOVE (>0 0) (10.75 0);

= MOVE (>0 0) (10.75 0.5);

Slots: 2.54 between centres

Should be

Bottom left: Slotted hole Holes 3 43 3 7.5 125.5 43 125.5 7.5