If your phono stage doesn't have a volume control and you go directly from that into an amp then the amp will be playing at max output because you don't have anything attenuating the signal coming from your phono.
If you are talking about going from your minimax into an integrated input and then line level out to an amp (hooked to speakers) then you are effectively using the integrated as the pre-amp while not using the integrated amp's drive unit. This can be done but I would not take out the drive tubes unless I confirmed with the manufacturer that it would do no harm. What you need is a pre-amp.
If you are talking about going from your minimax into an integrated input and then line level out to an amp (hooked to speakers) then you are effectively using the integrated as the pre-amp while not using the integrated amp's drive unit. This can be done but I would not take out the drive tubes unless I confirmed with the manufacturer that it would do no harm. What you need is a pre-amp.