DAS-703ES Passive LPF works

Meauring my passive LPF with 10mH inductor, to check if it matches to the LTspice simulation.

I turned off the DAC, input sine wave (from 20Hz to 1MHz) to just after IV stage, check the wave form both at the input point and LPF output point, just before the Line level output buffer FET.

The sine wave level is 2Vp-p, slightly below 16bit 0dB (full scale) level here. 40MHz analog oscilloscope with 10:1 probe. Higher level signal is at LPF input, lower at LPF output.

20Hz

100Hz

1kHz

10kHz

20kHz

40kHz

60kHz

100kHz

200kHz

400kHz

1MHz

It seems working as similar as the spice simulation, including the phase shift.

This is the wave form of 20kHz 0dB reference signal of the Audio Test CD. With DAC power on, and the coaxial SPDIF from CDP-553ESD.

You can see 2x oversampling digital filter of DAS-703ES is actually working as expected ;-)