The next step is to double click on this capacitor to bring up the “Capacitor Properties” dialog box, so that we can fill the missing initial voltages.

Now we add 4.25V in place of 0V inside the initial conditions edit box and adjust the test setup to reflect a much narrower time window.

After running the new test, with “Use Initial Conditions” checked, we the following results:

The results closely match those from the end of the 200mS run. (The second harmonic is –57dB in graph above.) Now that our confidence in the results has been boosted and the testing time substantially reduced, we can modify and tweak the circuit to our liking. For example, the source-follower FET can be replaced by a NPN transistor, such as the 2N2222 from Zetex (Zetex makes superior transistors, which makes them the perfect choice for the golden-eared), which may improve the performance by lowering the output impedance; or the capacitor C2’s value can be tweaked to cause a slight low frequency peaking.