MST MIDI to CV Converter - sYNTHROTEK - part 2

This is part two of my build of the Midi/CV converter from Synthrotek.

Part 1 is here:

MST MIDI to CV Converter - sYNTHROTEK - part 1

 

 

The MST MiDI to CV converter has been an easy job so far.

The components are all very nicely packaged and labelled.

Documentation is great.

 

 Finishing off the resistors on the logic board.

 

 

 

 

 

 

 

 

 

 

Just watch for shorts, esp the transistor voltage regulators.

 

My mobile phone (Samsung Galaxy 9 Note) has an amazing camera. 

The resolution is superb .

I have a microscope that I used to use to look for shorts, but I just use my phone these days. 

 

 

 

 

 

 

 

 

Time for the control board

ATTENTION: The zener diode for the MST Midi to CV Converter MUST be the Fairchild 4.7v Zener diode. The mouser part number is 512‐1N5230B. Other 4.7v zener diodes will NOT work.

Not sure how to tell the difference between the two diodes

Luckly my phone has good magnification.

You should be able to see 41 48 printed on one of the diodes.

Resistors next

Then the Trimmer pot

USB socket & jacks first.

Once I have the panel secured to the jacks , I solder .

 

Switches next

Two of these : the push button & the toggle.

 

 Install the DIN sockets

LED last

It's bi-coloured and has 3 leads.

 

For more info about LEDs:

https://djjondent.blogspot.com/2019/09/led-wiring.html

I usually install any ICs last.

These all go on the logic board>

tHIS first one is the PIC micro-controller (MCU).

Mine came pre-programmed. 

It's a pic18f2553. It's 8-bit.

The LT 074 is a op-amp of course.

The 6N138 is an optocoupler

+ Vactrols - Optocoupliers

 

The MCP4922 is a DAC ... a digital to analogue converter.

Nearly there...

Nice.

Links

+ Microcontroller Index Page

 

MST MIDI to CV Converter - sYNTHROTEK - part 1

 Building my first kit in a long time.

 

Finding a MIDI to CV converter is pretty easy in Eurorack format, but CV to MIDI clock converters

are rarer.

I'm looking for a module that will convert analog clock to MIDI clock.

Hopefully this will do the job.

according to the manual it does:

1. Clock input to DIN MIDI & USB MIDI CLOCK out

2. MIDI CLOCK to CLOCK OUT

Build notes (official)

+ https://www.synthrotek.com/products/mst-eurorack-modules/mst-midi-to-cv-converter/

+ Assembly instructions

The official build notes are great.

My notes are just to help me trouble shoot should I encounter any probs.

 

The supplied kit makes everything easy.

Sourcing parts is often more that half the work.

There are 2 boards: Logic & control.

Diodes first

all are 1n4148s

The 20Mhz crystal.

This is the clock source.

Caps next.

there are six 100nF caps - do these first.

c1, c4,c5,c9,c15,c16.

Four 51pF caps

c2,c3,c6,c8

Two 15pF ceramics

c7,c11

These go either side of the crystal

Electrolytic caps

c10, c13,c14

IC sockets

Spacers - standoffs -- headers

Once you screw in the standoffs, soldering the headers is easy.

Power (10 pin).

Switch & i2c header

 

   

 

The red switch sets the midi channel.

It's kind of a reverse binary number system

 

offoffoffoff = binary 0 = Midi 1

ONoffoffoff = binary 1 = Midi 2

offONoffoff = Midi 3

 .......

offONONON = binary 14 = Midi 15

ONONONON = midi 16 

etc

thAT  square shaped black socket is the header for a i2c connector.

It connects to the expander module.

Time for c12 

The 220 nF capacitor  is pretty big so needs to be twisted a bit to fit in nicely.

transistor voltage regulators

VR1 - 78L05

supplies 5V

 

TL431

U3

This is a shunt regulator or to use its long description, its a

programmable precision voltage reference IC.

 

It's a regulator diode whose output voltage can be programmed by changing the value of resistors connected to it. It's probably being used here to provide a voltage reference.

Data sheet

 

To be continued ......

Part two is here

MST MIDI to CV Converter - sYNTHROTEK - part 2

 

Links

+ Crystal Oscillators

+ Diodes - Basic Info 

+ Distribution  - power bus 

+ i2c protocol 

+ Microcontroller Index Page

+ Midi/DIN  to TRS 3.5mm

+ Integrated circuits - packaging  

 

Synthrotek Power supply - 5A build notes

 These are some personal notes for the synthrotek 5A PSU.

It's for eurorack systems.

It comes in 3 flavours

Red, Green & blue

This is a RED PSU.

 

Its ideal for small 1 row systems

I'm building a green PSU today

 

Its good for two rows of 104HP.

The Blue is suited for 3-4 rows of 104 HP

These are the voltage regulators'

-12V & +5V

I decided to install the switch and the power jack 1st since these hold the panel to the PSB

This is the USB connector

Orientate the LEDs so they sit nicely into the panel.

Don't forget the jumper

Caps-

square hole is positive

The orientation of the diodes and caps is slightly different from the RED PSU

Links

+https://store.synthrotek.com/Five-Amp-Power-Module_p_955.html

+ BOM

For the Blue PSU:

+ https://www.synthrotek.com/kit-assembly-instructions/modular-circuit-assembly-instructions/five-amp-assembly-instructions/