Is it possible to connect a graphic equalizer to a stereo or AV receiver that doesn’t have tape monitor jacks? Yes you can, as long as your receiver or integrated amplifier has In/Out jacks, like Tape In/Out, CDR In/Out or VCR In/Out. You might need an older receiver for this purpose.
Plug one end of the RCA jack to In on the Equalizer and the other end to (Tape/CDR/VCR) Out on the receiver. As long as the input source is analog, you will get the spectrum analyzer on the equalizer to light up. Digital sources will not work for this purpose.
When you upgrade to the latest and greatest receivers, equalization is really unnecessary as they are sophisticated enough to have its own equalization settings. Almost all come with automated equalization based on your room and speaker setup. You can also manually tweak the equalization in audio settings. However, some of us miss the visual spectrum analyzer display of a classic EQ system and that alone is worth setting it up to listen to you CDs or cassettes.
Using an older receiver, equalizer and tape deck, here is a setup example that only uses the equalizer as a spectrum analyzer display, adding old school sound visualization that you don’t get anymore with a modern digital setup.