I think you need something more rad but easier.
1. If funds are an issue, get an Ortofon 2M Blue and a Music Hall Mini phono amp ($80 online). If funds are less of an issue, Ortofon Black and a decent tube phono amp or preamp with phono and lose that old preamp.
2. To test and compare, use the same interconnect from phono amp output to amp as for CD to compare.
1. If funds are an issue, get an Ortofon 2M Blue and a Music Hall Mini phono amp ($80 online). If funds are less of an issue, Ortofon Black and a decent tube phono amp or preamp with phono and lose that old preamp.
2. To test and compare, use the same interconnect from phono amp output to amp as for CD to compare.