What do I need to set up my record player?

Ultimately, you need to convert the audio output from your pre-amp or receiver to a mono microphone input (or line-in) to your iOS lightning adaptor. Generally, you'll need the following (though some products are available which can combine some of these steps.)

• From your pre-amp, you will need to combine the left and right channels to a mono channel. Do NOT use a Y-cable, they do not properly combine the channels and you'll be very sad.
  • If your preamp output is RCA, you can likely use:
    • Channel combiner: https://www.amazon.com/Galaxy-Audio-JIBR-RCA-Combiner
    • RCA to 3.5mm plug: https://www.sweetwater.com/store/detail/CMR206--hosa-cmr-206-6-foot-3.5mm-trs-to-dual-rca-cable
  • If your preamp output is a 3.5mm stereo plug (standard headphone plug), you can use this:
    • Channel combiner: https://www.sweetwater.com/store/detail/MiniSumBox--switchcraft-318-mini-audiostix-1-channel-passive-laptop-direct-box
    • XLR to 3.5mm: https://www.sweetwater.com/store/detail/XVM101F--hosa-xlr-female-to-right-angle-1-8-inch-trs-cable-1-foot
  • It's possible that if your receiver output has HDMI, you can go directly from that to lightning, but I haven't tested this and it might not recognize the audio as a line-in device. If you try it and it works, mention it in a comment!
• What you now have is a mono signal, you need to convert this to a microphone input. There are a billion of these on the internet, here's one: https://www.amazon.com/ENVEL-Convertors-Smartphone-Microphone-Simultaneously/dp/B01M0T6PSF
• You'll then need your iOS 3.5mm to lightning dongle. That's this: https://www.apple.com/shop/product/MMX62AM/A/lightning-to-35-mm-headphone-jack-adapter