Measuring SAA7220 / TDA1541 O.S. vs N.O.S. modification

All These Measurements were at the output of a cd-player with and without the typical NOS modification.

Source Digital in 16 bits dithered frequentie. sweep 20Hz to 20kHz , -110 dB Philips low pass filter

output level in Non Over Sampling is 1 dB or 2 dB more depending on SAA7220p/A of SAA7220p/B and has a rolloff -3dB at 20 kHz

• Black NOS
• Red SAA7220 p/A
• Blue SAA7220 p/B

Level NOS and OS are  both 0 dBfs is 0 dBref – Source Digital in 16 bits undithered frequentie. sweep 20Hz to 20kHz , AES 17 filter

White noise , 16 bits undithered , sample at 192kHz , FFT 1m 10x average

Edit : 2026-05-11 :I hear and read that there is some unrest regarding the NOS measurement. 😉

I have doen some new OS vs NOS measurements with a -110dB Philips Low Passfilter. : Philips Low Pass Filter Measurement