Hi Robert and welcome to Beoworld!
You need to add an RIAA Pre-Amplifier between the Beogram and the BC2300. The BM3000 would have had a built in RIAA pre-amp.
Sounds Heavenly advertise this one and will supply the correct cable adaptors: https://soundsheavenly.com/products/pre-amp-bundle-for-b-o-beogram-and-all-turntables
Or this one from OneRemote would ‘future proof’ your system because if you buy a non-RIAA remote-controllable B&O turntable in the future it would allow remote control: https://shop.oneremote.dk/shop/69068-riaa-forstaerker/121270-riaa-iii-forforstaerker/
Location: Warwickshire, UK
My B&O Icons:
