Building the CV Scale Offset


BOM:

Qty
Value
Device
Package
Description
Source 1
Source 2
4100nCapacitor0603! 0603 Package !
610kResistor0805
11MResistor0805
21kResistor0805
21uCapacitor0805
120kResistor0805
12kResistor0805
2B10kPotentiometer9MM SNAP-IN9mm vertical snap-in pot, Alpha / Panasonic style with 6mm built-in knob.http://www.taydaelectronics.com/potentiometer-variable-resistors/rotary-potentiometer/linear/10k-ohm-linear-taper-potentiometer-round-knurled-plastic-shaft-pcb-9mm.htmlhttps://shop.erthenvar.com/collections/9mm-potentiometers/products/9mm-vertical-panel-trimmer
1LED5MMBicolour two-pin LED (red green)https://www.digikey.ca/product-detail/en/everlight-electronics-co-ltd/MV5491A/1080-1116-ND/2675607
2 M7 (1n4007)DiodeDO214Polarity protection diode.
33.5mm audio socketTHONKICONN3.5mm socket for Eurorack modular synths "Thonkiconn" style.http://shop.erthenvar.com/collections/accessories/products/3-5mm-inline-jackshttps://www.thonk.co.uk/shop/3-5mm-jacks/
1Tile power tail"Futaba J" type power lead.http://pulplogic.com/product/tile-tail/EBay
2TL072OpampSO08Almost any dual Opamp can be used.

Schematic:


Build Instructions:

Clean PCB with isopropyl alcohol to remove any manufacturing residues.

Solder the surface mount devices, then the remaining components.

 


Testing:

Inspect soldered connections for shorts.

Using a multimeter, check that there’s no shorts between the black, red, and white power leads.

Connect the power lead, and jack a bipolar LFO to the input and jack a multimeter or oscilloscope to the output and inverted output. With the knobs in the middle position (pointing up) the output should almost mirror the input, and the inverted output should be inverted.

Check that the knobs work properly. The “SCALE” knob should increase/decrease the amplitude, and the “OFFSET” knob should shift the input voltage positive and negative.

 


Done!