SGEYR RCA Switch 2 in 1 Out RCA switcher Selector 3.5mm Aux + RCA L/R Bi-Directional Stereo Audio Switcher A/B Analog Audio Switcher Black Metal Case

I assume that you are using the turntable with the output switched to the "LINE" position, so the signal is going through the turntable's internal RIAA preamp. Is that correct? If so, then you just need a simple passive switch like this one: https://www.amazon.com/SGEYR-switcher-Selector-Bi-Directional-Switcher/dp/B0GDTR6SVY/ref=sr_1_1_sspa Connect the turntable's output to IN/OUT-1. Connect the CD player's line level output to IN/OUT-2. Then connect the common IN/OUT jacks (located beside the switch) to the input of your speakers.

Best Buy Insignia turntable is on sale for $90 right now. https://www.bestbuy.com/product/insignia-bluetooth-stereo-turntable-black/J2FPJKYL84 Dayton powered bookshelf $130 - https://a.co/d/03OnkY0w Grab a RCA splitter - https://a.co/d/03ksc4JE And grab a working older DVD or CD Player from a thrift store to play CDs on. (Any DVD or Bluray player will play CDs also) And buy some decent RCA cables to connect all of it together. This gets you in for under $300 as a good enough starter system to enjoy music with.

Does that turntable have an internal RIAA phono preamp, and a "line level" audio output? If not, you will need to add a separate phono preamp. I looked at the specs for that turntable, it does NOT mention a preamp. If it doesn't have one, you need to add one. (But if it doesn't have one, I would think the level would be very low when connecting the turntable directly to the PA amp ... are you sure it sounds OK???) Once you have a line level signal from the turntable preamp, a simple selector switch like this one will be fine: https://www.amazon.com/SGEYR-switcher-Selector-Bi-Directional-Switcher/dp/B0GDTR6SVY/ref=sr_1_1_sspa Be sure to get one WITHOUT a volume control ... just a passive switch. That WILL work if it's connected correctly. Be sure your turntable output is set to "line level" and not the "phono" position. A "Y cable" which you call a splitter will NOT work, because you are not "splitting" anything ... you are combining. And you can NOT combine two outputs into one input, unless you use a selector switch or a mixer with an internal preamp. For your purposes the selector switch will be fine.