Re: Pat's Mic (Fetzer Valve Mic)
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Why do you need RD1 and RD2, wouldn't be one RD enough? Same for RS.Resistor?values for RD and RS need to be very specific, depending on IDSS, VP JFET values, and input voltage. Two resistors are used to make it easy to match the required values. Look at the ?page a the bottom, for the calculator.
Would we need a HexInverter or something else for the polarisation Voltage?
Yes, if you want to use a LDC capsule.
With the OPA and the Fet and T1 could there be a problem with the current from the Phantompower?
Yes, if the JFET IDSS value is to high. OPA1642 uses about 3.6mA. So, it is recommended to use a JFET with a low IDSS. The one I used has a 2.1mA IDSS value.
Regards!
HL
El jue, 14 abr 2022 a la(s) 02:16, Mic Scharf ( micscharf@...) escribi¨®: Why do you need RD1 and RD2, wouldn't be one RD enough? Same for RS.
Would we need a HexInverter or something else for the polarisation Voltage?
With the OPA and the Fet and T1 could there be a problem with the current from the Phantompower?
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