Re: Simple Op Amp RIAA preamp 1st lash up
Apart from resistor and capacitor ratios, the third time constant of 318us is the parallel combination of resistors times the sum of capacitors.
Which for resistors of 560k and 47k, and capacitors of 5.6n and 1.5n equals 308us (error of 3.8%).
Which validates a simple change of R6 from 680k to 560k.
All this supposes that there are no errors in capacitor values of course!
Craig
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