Send the spinstage back to the manufacture to check.
Transimpedance has too much gain?
I’m running an AT33PTG/II through an Andover Spinstage. Overall it sounds amazing but there definitely an emphasis on the 1khz region that makes some records hard to listen to. Its louder than the 20/20 and I have been swapping out parts to find the cause.
could the phonostage be adding too much gain?