hello Sir

I am new in this web site. i have confusion about my ckt which phase shift osc. i want to Generate 50Hz Freq using Phase Shift osc. for this vaule of resistor and capcitor is R=13kΩ and C= 0.1uf respectvely.now as per the Theory Gain is at least 29. so in Practically we can adjust this gain with any how? means Rf=30kΩ and Rin=1kΩ..etc but my circuit is not working in that type of gain adjustment. after R&D i select Rf= 2MΩ and Rin= 50kΩ. then after i can gererate a Freq but not 50hz. Gerenated freq is 329 Hz. i do not understand. why is this happen?
Can you Plz tell me what can i DO?
Thank you​

 

plz help me as soon as possible

 

Why don't you post your schematic?