These experts have found that the original PS1, model number SCPH-1001 actually sounds the best. I'm guessing that's because it came with RCA output jacks for the audio (and video too but we're discussing the device's audio qualities). That means you can use any RCA audio cable you like. Later models came with different innards as well as a proprietary output wire system that some believe is second rate.
I've tested a SCPH-1001 and a later SCPH-9001 and can honestly say they both sound really, really terrific. My new 1001 is currently having problems (more about that in a minute) so a direct comparison is not possible at the moment.
But I can say that both models sound better than they probably have any right to sound -- terrific midrange, good bass and slightly rolled-off highs. Don't just take my word for it. My friend, audiophile Art Dudley, writes in the latest Stereophile that he and his wife preferred the sound from his test PS1 to his expensive Sony component CD player. Stereophile's editor, John Atkinson, added that the PS1 didn't test very well but sounded pretty good when he heard it playing as part of an affordable hi-fi system.
Since word started to get out about the PS1's amazing audio qualities, prices have started to skyrocket. These game devices used to sell, on eBay (EBAY - Get Report), for anywhere from $10-$25 depending on the console's condition plus how many controllers and game CD discs were included in the deal.