Typically you should be able to connect your preamp to the tape in of the integrated amp which should at least bypass its tone controls and maybe the first stage of the integrated amp. You can then use the preamp for all the input connections for your stereo. You can also cut off the preamp and maintain all the inputs for your HT into the integrated amp( except for its tape input).
If however your goal is just to add phono, I agree with Nrchy & Paul G.
If however your goal is just to add phono, I agree with Nrchy & Paul G.