mikeyb wrote:Hi Joe, would you implement the filter like in my above jpeg?
If Rload fixed or variable? What value is it if fixed?
Rf need to be low enough that the opamp output doesn't move to may volts offset as it will limit headroom and make loud bangs as HPF is bypassed.
e.g If Rf = 100k then Cf = 18nF = 88Hz or 22nF = 75Hz
If Rload is fixed it is best moved to the Rf position as it will be a lot lower in resistance so opamp offset will be a lot less.
Let me know the actual transformer and opamp and Rload values etc and I will be able to better advice what to do