How cheap? Discontinued AT-LP120 or new X version AT-LP120X? Does it need a new stylus?
What’s the difference between a TS cable and TRS cable?
The JBL or Nobsound should work.
More options:
Low cost Level Controller.
Monitor controllers with pro audio connections:
Or a Stereo Preamp with RCA inputs and output.
Or use a mixer.
Looks like the Subzero is a phono preamp, not a stereo preamp.
Looks like the Lenco has an inexpensive low sound quailty ceramic cartrdige with line output so you don't connect it to an RIAA phono preamp. You would only connect an RIAA phono preamp to a turntable with a better MM moving magnet cartrdige that does not have a built in phono preamp or has a switch to bypass the built in phono preamp.
For studio monitors you would use a level controller, a monitor controller, a mixer or a stereo preamp, not a phono preamp.
You already had the Adam monitors or did you buy them for the turntable you just purchased?
Instead of digitizing the analog turntable audio signal try bypassing the digital interface and computer and connecting the turntable to the studio monitors with a level controller, a monitor controller, mixer or stereo preamp.
Monitor controllers to connect both the turntable and the interface so you can switch between them:
Stereo Preamp with RCA inputs and output.
Don't expect vinyl to sound as good as digital, it's just different with it's own sound and quirks.
Wet clean new and used records.
You don't need an audio interface unless you also plan to record instruments to your computer in addition to recording the turntable to your computer.
All you may need is the simple level controller, or a mixer or monitor controller or a stereo preamp. Mixer or monitor controllers will also often have RCA inputs and XLR or TRS outputs to connect to the studio monitors if they don't have RCA input.
What have you had the Kali connected to?
Turntable > phono preamp > level controller, monitor controller, mixer or stereo preamp > studio monitors.
Phono preamps:
Volume control, 2 input switch and phono preamp:
RCA volume control:
Volume control and switching with multiple connection formats:
Level Controller if you won't be using anything else besides the turntable with the studio monitors.
Schiit Sys has 2 RCA inputs switch with RCA output and volume control.
Nobsound MC2 has both RCA and XLR input and outputs if in addition to the turntable you want to also connect to an XLR audio source.
You really don't want to use the wrong bass knob, that can short-circuit an amp and fry it. Here's the kind of aftermarket knob that's safe to use: https://www.amazon.com/PAC-LC-1-Remote-Amplifier-Controller/dp/B0002J226O/
Otherwise, you gotta email whoever made the amp and ask how much for a new knob. Accept no substitutes if you're plugging into the RJ11 bass knob port.
Level Controller or Stereo Preamp or a mixer or monitor controller.
Picked up the RT81 for sale on Black Friday?