Since I at some point used to prefer the analog inputs of the FusionAmp, I wanted to find out why. Are there measurable differences, or was in all in my head? My findings support the latter I'm afraid, although the digital input seems to have slightly more distortion than the analog. Not that I think it could ever be audible...
I measured this using REW. The source was a WAV-file measurement sweep played back from my Logitech Transporter streamer. I used a Focusrite Scarlett 2i2 Gen3 USB interface to capture the speaker output signal from an FA252 FusionAmp, which was connected to a 4 ohm dummy load. The output level from the FusionAmp was set at -18 dB, or somewhere around 4W @ 4ohms. The Scarlett is not exactly on the level of an AP analyser, but for this purpose good enough. The graphs below show the analog out from the Logitech Transporter as well for reference, which is way below the FusionAmp.
The rise in distortion at high frequencies is a bit alarming to me. It's certainly not due to the NC252 amp modules, so it must come from the DSP board.
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