Thank you for purchasing the MST Noise / Sample & Hold / Track & Hold Eurorack module kit!  This is an intermediate build.  If you feel like you can handle it please proceed!  If not, get some help from a friend with experience or purchase a fully completed unit.  This kit also requires the builder to use an oscilloscope and a spectrum analyzer to properly calibrate the unit once complete.

Please follow the BOM and these instructions and don’t populate from the PCB alone. Also sometimes we cannot get the exact pictured components, so please look over your parts and check the codes first.

Please note: this build MUST BE DONE WITH LEAD SOLDER.

Lets begin!

DIODES

Start with the  diodes as shown below, then turn over on a firm surface to solder, then clip your leads.  Diodes are polarized components so you must match the black stripe on your diodes with the white stripe on the PCB silkscreen.  Please note that D4 is an SD103C diode.  The S&H portion of the circuit will not work unless you use this exact diode. This diode should have a voltage drop of ~.3 volts. 

RESISTORS

 Populate first, then turn over on a firm surface to solder and clip leads.  Using a flat rigid card or another PCB can help hold the resistors in place as you turn the board over.

SOCKETS

Place the IC Sockets by aligning the notch with the notch graphic on the PCB Silk Screen.  Turn over on a flat surface and solder into place.

CAPACITORS, TRANSISTOR & TRIM POTS

Add the non-polarized capacitors as shown below.  Turn over to solder and clip leads.

Add the transistor by matching the flat side of the transistor with the flat side on the silk screen, turn over to solder and clip leads. Next, make sure you orient the electrolytic capacitors in correctly.  The longer lead needs to be inserted into the hole that has the “+” marking near it.

Next, insert the trim pots into their appropriate spots, taking care to orient them as in the picture below. Now you can turn your project over onto a flat surface, solder and clip leads.

 INTEGRATED CIRCUITS & 16-PIN POWER HEADER

Place the ICs in place by aligning the notch with the notch graphic on the PCB Silk Screen and notch on the sockets. Next add the 16-Pin Eurorack Power Connector in place by matching the key notch with the key indicator on the PCB silk screen.  Turn over on a firm flat surface and carefully solder all of the pins.

 JACKS,  SWITCH & PANEL

Place the the jacks in and on a flat surface solder (for now) ONLY THE CENTER PIN of each jack to the PCB. Make sure the Jacks are tight to the PCB.

Now place the panel on the jacks as shown below and tighten down all of the jack nuts.

Once you have lined up the panel to the board, and made sure that everything is nice and flat, go ahead and solder the remaining pins on the jacks.

Now take your SPDT switch and remove all nuts except for the last nut as shown below and unscrew that nut just as the photo shows.

Place the switch behind the panel and tighten down the other nut firmly to the panel.

Make sure the switch is aligned perpendicular to the PCB, just as shown below.

Take 3 of your leftover resistor leads and make some hooks as shown below.

Place the hooked leads on the switch solder lugs, one at a time, and solder

When you have finished soldering all of the hooked leads, the switch should look as it does below.

Congrats!  You are now ready to test and calibrate your module.  Thank you for choosing Synthrotek!

 

Noise Calibration

Roughly Center all four trim pots.

Place the scope probe on the White Noise output prior to the 1K output resistor R3.

 

Set the spectrum analyzer frequency range to cover roughly 20Khz.

Trim the Noise Adjust RT1 until the noise spectrum is of roughly equal amplitude across the whole spectrum.

Trim the White Noise Gain Trim RT2 until the scope trace indicates peaks slightly past +/-5V output.

 

Now place the scope probe on the Pink noise output prior to the 1K output resistor R8.

Trim Pink gain RT4 until the scope trace indicates peaks slightly past +/-5V output.

Now place the scope probe on the Slow noise output prior to the 1k output resistor R8

Trim the Slow random Gain RT3 until the scope trace indicates peaks slightly past +/-5V output.