how to connect Audio-Technica AT-LP70X RCA to get MP3 output. Can someone inform me please
If you have a desktop/tower speaker with a regular sound, plug it into the line input (normally blue). Of course you will need the appropriate adapter cable.
If you have a laptop with only mic-in and headphone-out you’ll need a USB audio interface with line inputs. The Behringer UCA202 or UCA222 is popular and relatively inexpensive.
Those Behringer’s don’t have a recording level control which means you an potentially clip (distort) the analog-to-digital converter inside the interface. (It doesn’t seem to be a common problem.)
I have an ART USB Phono Plus, which does have a recording level control. It’s more expensive at about $100 USD. Or there are lots of higher-end audio interfaces with switchable pro-microphone and line inputs.
Don’t get a regular “USB soundcard”. They are like laptops with only mic-in and headphone-out.
When you record with Audacity you get uncompressed audio. After recording you can export as WAV or MP3, etc. You can also save as an Audacity Project AUP3 file (which only works in Audacity) but that shouldn’t necessary with what you’re doing. (I rarely make a project.)