Here's a GREAT idea! BECAUSE this is such a nice but older Sony... "I" would use a Blu-Tooth SPEAKER with a AUX speaker input! LOTS of AUDIO and VERY inexpensive too!
I recently bought a BlueTooth TRANSMITTER/RECEIVER that has a 3.5mm" Jack right from it's body! Depending on the 'mode'
it's in ~ it will TRANSMIT audio (like from your Sony) to a Bluetooth Speaker! (In it's second mode it acts like a BT RECEIVER.)
Here's a official title of another:
Mini Bluetooth 3.5mm Music Audio AUX Wireless Transmitter
and it's about $7!
This puppy is a Bluetooth TRANSMITTER only.
"This device can transmit music from your media devices(smart phone, iPad, mp3, CD/DVD player , TVs and more) to your Bluetooth-enabled equipment (bluetooth speakers/Bluetooth headphone, etc) simultaneously"
THEN there are THESE "3 Watt" BLUETOOTH RECEIVERS for UNDER $2 ! I KNOW! Hey man ~ just pick your color!
eBay: 112673621308 DANG ~ I'm going to order some now!
MMMmmm try earphones? How is the volume then? Plenty?
ALSO earphone jacks become dirty
and the contacts that SWITCH THE SPEAKER OFF become poor conductors that starve the speaker for volume... anything more than this MAY constitute a MAJOR repair cost...
SO KEEP your SONY and consider the options!