Using Victor's Oscillator as reference (1kHz, ultra-low distortion analogue sine generator). A quick peek at the APx555B Analogue & DAC Signal Generators @1kHz. And on playing music "for fun"!

Note the 2-pin power connector on the lower left.As you've seen on the blog over the last year, I've been using the E1DA Cosmos ADC from Ivan Khlyupin for a number of measurements recently (early report discussed here). I remain quite impressed by the performance of this little device with some caveats (lower input impedance, individual unit idiosyncrasies including what "grade" device one has).