First cycle distortion - Graham, what is that?

All this is just.... old, dated and surpassed many times in performance.

It depends on what you mean by performance.

If you understand the output power, load capacity, THD on a sinusoidal signal in steady state, then yes, these parameters are much better for modern amplifiers.

However, let's try to figure out what Graham put into the concept of FCD.

Here are tests of two amplifiers at the same output power on the same resistive load. On a reactive load, what the acoustic system actually is, the contrast would be even greater!

According to my understanding, the difference is related to the group delay, which, unfortunately, the developers still do not pay due attention to.

For example, John Curl pays special attention to the 7th harmonic and above.

Judge for yourself.

Unfortunately, the FCD test cannot be run on MicroCap versions higher than 9.


  • JLH-69_36V_20kHz-FCD.png
    24.1 KB · Views: 72
  • JLH-69_36V_20kHz-spectr_2-period.png
    24.4 KB · Views: 70
  • BC-1_20kHz-FCD.png
    28.7 KB · Views: 77
  • BC-1_20kHz-spectr_2-period.png
    29 KB · Views: 78