Yes, it could be a super noticeable difference. It may depend on the quality of your phono stage to begin with as well. I think sound quality could be improved in two ways:

1. Generally, you will get much better bass definition just because the new power supply has that much more juice available on demand.
2. By switching to a linear power supply, this will result in much cleaner power delivery and much cleaner highs as a result.

Rule of thumb: Spend as much as you can until you get an anxiety attack.

Us audiophiles are DESPERATELY need of help! We need help with making our systems look good and desirable. Solve this problem and you will have it made - with wannabe audiophiles! HaHaHa. But that market is probably for your taking.