Hello
I think that the DD9 has a 20-20,000 Hz frequency response, but does anyone have a user manual to confrim this from the specifications listing?
Thank you

Under DC2 specs search this :
The DC2's S/N ratio is 58dB for a type IV tape, falling to 54dB for a type I, while the DD9 measures 48dB (no tape type specified).

W/F: DC2, 0.07% WRMS (NAB), DD9 0.13% WRMS (NAB).

The DD9 manual talks about a total harmonic distortion of 1% (which I think is for 5mW x 2 into 16ohm headphones, although the manual could be clearer on this point), whereas the DC2 manual specifies 10% at a power of 20mW x 2 into 32ohm headphones. I did have the datasheets for the two different headphone amp chips used in these two walkmans, and I seem to remember that the DD9's looked better in terms of distortion, but I can't remember what the relative power outputs were.

Frequency response: DC2, 40Hz-15kHz, +/-3dB. For the DD9, it's 20Hz-20kHz, although without specifying any tolerance, this might not be as good as it looks (it might be +/-6dB rather than 3dB). Having said that, the DD9 does sound to my ears as if it has more extended treble, although Sony might just have over-EQ'd the high-frequency response, which might explain why the DD9's S/N ratio is as bad as it is.

The plus or minus db rating can significantly alter actual performance specs.

Cool. Thank you, John.