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Comment: complete review on 2024 builds and QA

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ISSUES

Nr.DescriptionPriority
Solution
1Switches - use other pcbs footprint size and/or change panel to toggle switch1

2BOM : LOG for Volume LFO and VP out gain3
fixed
3missing mounting holes for pcbs2
open
4LED driver needed for gate led2
fixed
5leds polarity on pcb3
fixed ?
6LFO speed inverted pot, left is fast on the prototype1Or use reveresed Potifixed
7panel holes too big for potis1
open
8powersupply design not allowed -2
open - use a own PSU - Yamaha PA30 and resctifier, capactitors
9markers for voltage test points missing3
open
10more clearly infos about matched trannys and resistors3

11envelope change too CEM3310 or digital1
open
12capacitors are too close next to the power supply section on mainboard1
fixed
13use bigger traces1


open
14Gate signal bleed in LFO1Blockerfixed
15V/oct unstable - waveforms wobbling -1Blockerfixed
16Lfo led not working3
fixed
17Holes in vcf board and VCO board to mount on metal spacers - for better mounting2
open
18Case doesn't fit with the panel1
workaround possible
19ua7261
use normal matched pair trannys
20ssm20401
use the new SSI 2040 !!
21



22knobs ask Patrick_H



BOM: 11-2020

rsf-kobol.xlsx

changes:  

 in crazy.p clone R135 ---> 68pF

 in Crazy.p clone R207 ---> 22nF

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Panel Wiring 11-2020

Project schematics RSF Kobol Expander I Clone.pdf


please note the 3Pin Connectors are wrong in the Wiring guide !! 

Ground is the middle pin on the 3Pole connectors.

for all jacks:

S is to be connected on TIP Pin (hot)

SW is the Tip Switch Pin (for grounding when no plug is in the jack inserted)




Switches

needed:  1x 2 rows with 3 pins (ON/OFF) power (DPST)

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mouserordered (tick)
power

MHS222K not avail.

06-MHS22204
https://www.kynix.com/Detail/176774/MHS222K.html
4x normal
MHS122K

apem

home stock






5cooler
Nr




Pots

50€ thonk T18 shaft or round shaft- you need 2 center pots and 1-2 Log

100KB

2xx 100kA

100KB center detent for tune and vco2 beat optional for Freq. its up to you.


look at crazy patroches pic and in the BOM


jacks

35€45€

resistors

30

capacitors2,2MFreichelt30€5euro

ICs: 3080, lm324, lmxxx

estimated 100€

trannys, Power reg.

5

diodes

12

switches mouser

10-20

cable and headers

20

SSM20502x
480€ or ask me for a replacement VCA/ADSR PCB to use CEM3310/AS3310

heatsinks2x
5

external Yamaha PA30

50€

SSM2040

Ebay 50 or use new SSI2140 with adapter 10€

case

Buchla boat from SAMODULAR - cut the frame to make it fit 100€

ic sockets

10-15€


Yamaha PA-20 powersupply

40€



knobs tme

GWB19BK

LEDS 3x 
red 






Calibration

  1. VCO: linearity = High Freq. compensation. = there's a 1Mega Resistor which is connect to the Trimmer - adjust the Trimmer as close to 0V  (which is a OFFSET and affect the V/Oct calibration)

Image Added


2. VCO 1V/Oct as normal with Guitar tuner method or Freq. Counter/DMM



Schematics:

ob_345da9_schemas-carte-kobol-expander-1.pdf

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