IntroductionThe Ultimate Pre-amplifier features a soft clipping feature which when enabled, clips in much the same way a push-pull tube amplifier does but does so more accurately and consistently since it is implemented in the digital domain.
Measurements
- Soft Clipping of 1kHz sinewave at 0dBFS. (https://analog-precision.com/forum/performance-and-measurements/soft-clipping-test/msg55/#msg55)
- Soft Clipping of 1kHz sinewave at -10dBFS. (https://analog-precision.com/forum/performance-and-measurements/soft-clipping-test/msg56/#msg56)
- Soft Clipping of 1kHz sinewave at -20dBFS. (https://analog-precision.com/forum/performance-and-measurements/soft-clipping-test/msg57/#msg57)
- Soft Clipping of 1kHz sinewave at -30dBFS. (https://analog-precision.com/forum/performance-and-measurements/soft-clipping-test/msg58/#msg58)
- Soft Clipping Sweep of THD + N vs Amplitude of 1kHz sinewave. (https://analog-precision.com/forum/performance-and-measurements/soft-clipping-test/msg60/#msg60)
ConclusionThe soft clipping works extremely well and in textbook fashion according to the measurements below. In fact it works so well there are no more distortion artifacts above 3rd order so even the most ardent of tube aficionados would welcome its tube like characteristics which can be turned on or off at will.
Soft Clipping (Scope).png
Symmetrical clipping means the absence of 2nd harmonic distortion and dominating 3rd harmonic distortion but no higher frequency distortion artifacts which should be music to the ears of tube aficionados.
Soft Clipping (THD+N).png
Soft Clipping (-10dBFs)(THD+N).png
Soft Clipping (-20dBFs)(THD+N).png
Soft Clipping (-30dBFs)(THD+N).png
Below -35dBFS the measurements are dominated by noise !
Soft Clipping (THD+N vs A).png