Question about the Sigma Project

[makinrose]

Hi makinrose

Sigma nominally has a low-z output due to the feedback around the mixing stage. You should build it as is and try it with a long cable and a short cable to hear if there's a difference. If there, the best solution is to add a BJT buffer directly to the mix stage plate. Surprisingly, this provides a better frequency response than a mosfet would.

Have fun

Excellent! Thanks for the help.  If necessary the BJT will be easy to add.