The Tiny SA is only specified for frequencies >100 kHz.
I notice the sweep is from 3 kHz to 103 kHz.
I'm surprised you have been able to obtain a trace that looks anything as good as the ones you have, when used at that low a frequency.
The differences in traces is probably due to minor hardware variations and internal noise generation, as it is being used well outside of its specified range.
I think you just got lucky with one device performing better than the other, due to a variation in manufacturing tolerances.
Regards,
Martin
