You've got me thinking. I'm willing to bet the built in pre of the 1500c is no better than the cheap options like the Schitt or even this one (I have 78's as well---and will be getting a dedicated mono/78 cartridge)
https://www.needledoctor.com/Esoteric-Sound-Rek-O-Kut-Ultra-Phono-Preamp
https://www.needledoctor.com/Esoteric-Sound-Rek-O-Kut-Ultra-Phono-Preamp

