Hi,
Is this phono stage part of a preamp or integrated amp? 23.5dB doesn't make any sense for a separate phono stage. "Normal" MM gain is 40dB and 60dB for MC.
Sometimes a preamp or integrated will have less gain in phono if there is a lot of gain in the line stage, but 23.5dB seems too low even for that.
What specifically do you have? It's probably designed for a ceramic cartridge. They put out mucho voltage and will usually overload a MM stage.
neo