We find that wiring a MFOS PCB to the front panel controls is both time consuming and often detracts from the overall finish. We are not able to alter the MFOS PCBs to make panel wiring easier so we approached the problem from a different angle. We chose to mount the front panel controls on a mini PCBs (breakout boards) that take the panel controls to a JST type XH socket into which is plugged a lead (not included with set but available separately). This lead is then dressed to the main MFOS PCB (or sometimes to other panel controls) and soldered into the respective pads. Many breakout boards have solderable jumpers for making common connections as well as thin tracks to cut where panel mounted resistors need to be connected inline with say a pot wiper. MFOS projects may require multiple breakout boards so we bundle these altogether and offer them in one ST Synth Panel Breakout PCB Set. The pack description will further describe the wiring colour code and what if any links need to be made or cut.
This method does have other advantages other than just time saving and appearance:
- Time saving
- Neater more professional appearance - improves resale value
- Takes care of common connections between panel components
- Has space to accommodate panel mounted resistors and capacitors
- Can improve reliability - have you tried soldering a diode, LED and a wire to one pin on a toggle switch on the 16-step sequencer?
- Makes fault finding easier
If you have any reservations about using connectors, then simply solder wires direct to the breakout boards. Takes longer but you still get all of the other advantages.
The boards are designed to fit our front panel component spacing so you will see references to pitch and whether it is in the 'x' or 'y' or both direction. At the time of writing, there was 30+ breakout boards developed for pots (using pot brackets), sockets (jack and banana), switches and LEDs. Whilst these will not take care of every panel component on over 40 MFOS projects, it will go a long way to achieving it. As we work through making up each MFOS project with these breakout boards, we will see where improvements can be made or even create more breakout boards to provide the best possible solution.
The panel PCBs can also be used with our YuSynth range. YuSynth PCBs are better laid out as regards panel wiring but can still take advantage of these breakout PCBs.
This pack contains the following breakout PCBs:
- 7210-704 x 1
- 7210-722 x 1
Whilst you can solder wires between the breakout PCBs and the main PCB, we do recommend using our JST cable assemblies. For the VC Reverb, you will need the following:
- 7210-105 x 1
- 7210-112 x 2
See the Build Guide tab for wiring information on how to use these breakout PCBs with this module.
Whilst our breakout PCBs make the task of building a module easier, it still should only be undertaken if you have a reasonable understanding of assembling electronics and soldering. We have taken all reasonable effort to document this build below but should you find any errors, please let us know by posting on the FAQ tab, thank you.
- Assembled MFOS PCB #7210-065
- Front Panel #7210-565
- Back Panel #7210-865
- PCB Holder #7210-965
- 4-Way Pot PCB #7210-704 (1 reqd.)
- 4-Way Jack Socket PCB #7210-722 (1 reqd)
- 5-way Cable Assemble #7210-105 (1 reqd)
- 12-way Cable Assemble #7210-112 (1 reqd)
- Bracket Kit #7210-181
- PCB Mounting Fixing Kit #7210-182
- Pot mounting brackets #7300-000 (3 reqd)
- Additionally you will need our Switchcraft Jack Sockets #7212-200
4-Way Pot PCB Preparation
Firstly, make sure the solder bridges D, H & G are soldered.
Solder in JST header noting that the slots in the socket housing point towards the top of the board.
- Remove any anti-rotation lugs on the pots
- Insert pot into bracket and temporarily do up lock nut
- Insert pot with bracket into PCB and solder in position ensuring the pot bracket sits flat on PCB. Only solder the bracket lugs on the bottom of the board. Note three pots are used, do not put a pot in the position below R4, R5, R6 resistor legends.
- Repeat for remaining pots
- Remove pot nut
4-Way Jack Socket PCB
Solder in JST header noting that the slots in the socket housing point towards the top of the board
Fit the sockets to the panel noting that the mitre corner is positioned bottom left. Place the PCB over the socket pins and solder in place.
The offical MFOS PCB differs slightly from the instructions / PCB layout on the MFOS website. The VC Reverb was the last product from Ray Wilson before his passing. We have identified what we believe is the only difference which is a few components to form a high pass filter. The components involved are R9, R39, R40 & C27.
R40 (100k) is solder on the rear of U1 between pins 3 & 4.
R9 (10k) is soldered to C27 (22nF) before soldering into the R9 position. It is important the resistor and capacitor are soldered exactly as per the photo below. R39 (1k) isoldered from the casing of the phono socket to the junction of R9 and C27.
Assemble the panel PCBs and the MFPS PCB and PCB holder as in the photos below.
Next solder wires to the LED and connect to the pot PCB. The LED cathode is soldered to the R4 pad and the anode to R5.
Plug in the JST lead into the pot PCB and solder the wires as per this table:
|1||Black||0V (pad below X8)|
|3||White||Cut, not needed|
|4||Yellow||Cut, not needed|
|6||Green||Cut, not needed|
|10||Brown||Cut, not needed|
|12||Red||Cut, not needed|
|4||Yellow||Wire to pad R3 on the pot PCB|
|5||Orange||0V (pad to the side of X8|
Photo below shows the module under test with the spring reverb unit
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