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
- 7210-751 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 Phase Shifter, you will need the following:
- 7210-105 x 1
- 7210-106 x 1
- 7210-112 x 1
See the Build Guide tab for wiring information on how to use these breakout PCBs with this module.
Guidelines when building the 8-stage phase shifter module using our panel PCBs, front and back panels, PCB holder and the MFOS main PCB.
- Assembled MFOS PCB #7210-060
- Front Panel #7210-560
- Back Panel #7210-860
- PCB Holder #7210-960
- 4-Way Pot PCB #7210-704, 1 off
- 4-Way Jack Socket PCB #7210-722
- 2-Way Toggle Switch PCB #7210-751
- Pot brackets #7300-000, 4 off
- 3x3 Jack Socket PCB #7210-733
- 5-Way Cable Assembly #7210-105
- 6-Way Cable Assembly #7210-106
- 12-Way Cable Assembly #7210-112
- PCB Holder Brackets Fixing Kit #7210-181
- PCB Mounting Fixing Kit #7210-182
- Additionally you will need our Switchcraft Jack Sockets #7212-204 (Pack of 4)
Panel PCB Preparation
There are 3 panel PCBs for the pots, jack sockets and the toggle switches.
Refer to the photo below of the assembled pot PCBs when following these steps.
So, starting with the pot PCB
- Solder link F
- Solder a wire link between R1 and R2 (not actually shown in the photos below simply because it was missed!)
- Cut the track behind R10 (see photo below)
- Solder a 100R resistor in position R10
- Solder in JST header noting that the slots in the socket housing point towards the top of the board on the pot
- Remove any anti-rotation lugs on the pots
- Not all of the pots are the same value so it is important to get them right. The PCB has 4 groups of resistor positions labelled R1 to R12. The 100k linear pots go in positions under R7 to R12. The 100k log for the input level below R4-R6 and the 10k in the remaining position.
- 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
- Repeat for remaining pots, note
- Remove pot nut
The toggle switch and jack socket PCBs only need their JST connectors soldering in.
Assemble the front panel components as per the photo below noting the orientation of the pot PCB and PCB holder and its associated fixing brackets.
Now comes the wiring of the JST connectors.
Dress and solder the wires to the main PCB and breakout PCBs. We tend to route the wire first to get a final length before cutting. The cut end is then stripped and tinned and placed into the respective pin on the MFOS PCB. With a fine tipped soldering iron (<1mm), we then solder the wire in position from the top of the PCB. We each have our own preferred method but this works well for us.
4-way Pot PCB
|6||Green||Cut, not needed|
|4||Yellow||Cut, not needed|
|2||Red||Cut, not needed|
|1||Black||Cut, not needed|
Toggle Switch PCB
|2||Red||R2 pad on pot PCB|
|6||Green||Cut, not needed|
* Note the red wire above is soldered into the remaining R2 pad on the pot PCB
Jack Socket PCB
|4||Yellow||R6 pad on pot PCB|
* Note the yellow wire above is soldered into either of the R6 pads on the pot PCB
Note where the brown and blue wires from the pot PCB connected to the ground pads. The orange ground wire from the jack socket PCB can be soldered into one of the ground via pads below U4.
Wiring is now complete except for the +/-12V supply whcih depends on your own system. We solder in a 3-core cable with a plug on the end (see photo above) which we use for power distribution in our racks. Next is a visual inspection and we also apply power before inserting chips to check for correct polarity across one of the IC sockets.
No FAQ found
No posts found