{"product_id":"voltage-controlled-amplifier-vca","title":"Voltage Controlled Amplifier – VCA","description":"\u003cp\u003eThis  is a\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eVoltage Controlled Amplifier\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e(VCA). A VCA board helps users control the Audio Level from a remote potentiometer. It requires a single-ended audio signal in the input. Gain control voltage can be adjusted through an on-board potentiometer or use an external potentiometer connected to CN4. The project works with a dual\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e±15V\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003epower supply. Screw terminal connectors are provided for signal input and signal output. The project is built using\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eTHAT2181LA\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003echip, a VCA that is designed for high-performance audio-frequency applications requiring exponential gain control, low distortion, wide dynamic range, and low control-voltage feedthrough. These parts control gain by converting an input current signal to a bipolar logged voltage, adding a DC control voltage, and re-converting the summed voltage back to a current through a bipolar antilog circuit. Stereo control of\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eVCA\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003ewith a single potentiometer is possible.\u003c\/p\u003e\n\u003cp\u003eTHAT 2181-series trimmable Blackmer voltage-controlled amplifier (VCAs) ICs are very high-performance current-in\/current-out devices with two opposing-polarity, voltage-sensitive control ports. They offer wide-range exponential control of gain and attenuation with low signal distortion.\u003c\/p\u003e\n\u003ch3\u003eTrimming\u003c\/h3\u003e\n\u003cp\u003eThe trim should be adjusted for minimum harmonic distortion using PR1. This is usually done by applying a middle-level, middle-frequency signal (e.g. 1 kHz at 1 V) to the audio input, setting the VCA to 0 dB gain, and adjusting the SYM trim while observing THD at the output. In\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eTHAT2181LA\u003c\/strong\u003e, this adjustment coincides closely with the setting which produces minimum control-voltage feedthrough, though the two settings are not always identical.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003ePower Supply +\/-15V DC @ 40mA\u003c\/li\u003e\n\u003cli\u003eGain Range -100dB Min-+20dB Maximum\u003c\/li\u003e\n\u003cli\u003eTotal Harmonic Distortion 1V 0dB Gain 0.0025%\u003c\/li\u003e\n\u003cli\u003eScrew Terminal for Single-Ended Audio Input\u003c\/li\u003e\n\u003cli\u003eInput Impedance, Audio 20K Ohms\u003c\/li\u003e\n\u003cli\u003eScrew Terminal for Audio Output\u003c\/li\u003e\n\u003cli\u003eOn Board Power LED\u003c\/li\u003e\n\u003cli\u003e5mm Mounting Holes\u003c\/li\u003e\n\u003cli\u003ePCB Dimensions 60.96 x 23.50 mm\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eConnection\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eCN1: Pin 1 = Audio Signal Input, Pin 2 = GND\u003c\/li\u003e\n\u003cli\u003eCN2: Pin 1 = Audio Output, Pin 2 = GND\u003c\/li\u003e\n\u003cli\u003eCN1: Pin 1 = +15V DC, Pin 2 = GND, Pin 3 = -15V DC\u003c\/li\u003e\n\u003cli\u003eR9: Gain Adjust Potentiometer\u003c\/li\u003e\n\u003cli\u003eCN4: Optional External Gain Adjust Potentiometer\u003c\/li\u003e\n\u003cli\u003eD1: Power LED\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"dotfry","offers":[{"title":"Default Title","offer_id":47197196058796,"sku":"A130","price":35.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0757\/6436\/7532\/files\/A130A.jpg?v=1789304168","url":"https:\/\/dotfry.com\/products\/voltage-controlled-amplifier-vca","provider":"dotfry","version":"1.0","type":"link"}