Connecting turntable to new iMac doesn't work, but old iMac did
For the past few years, I had my Rega RP1 turntable connected to a TC-750LC phono preamp (TCC Audio & Video) and then connected to my 2011 iMac, which was running macOS Sierra. My old iMac had a dedicated line-in port. The software that I used (and still use) is VinylStudio. It all worked great.
A few days ago, I upgraded to a new iMac, which is running macOS Catalina. I still have my Rega and my TC-750LC phono preamp. I did change the wire between the preamp and the computer to be two male RCAs (preamp) to a USB-C (computer). I can see this connection in the "Input" tab of my Sound preferences. However, I can't get any sound (other than white noise) from the turntable to be heard from my iMac. I'm not getting any sound level.
I did connect a U-Turn Audio turntable with built-in preamp directly to my iMac. With the preamp off, I heard nothing except white noise. When I turned on the built-in preamp, I got interference sound, and when I turned on a record, I got some vinyl noise, so at least it seems like my RCA/USB-C wire works in theory.
I'm not sure what to try next, although I haven't tried an RCA/USB-A wire. Any other suggestions to try first before spending more money?
iMac 27″, macOS 10.15