The Toft AFC-2 would be a good idea for your synths and MPC without breaking the bank. It has a highly musical 4-band EQ that might be very useful for dialing in the tone of your synth and fattening up the kick's and snares for your MPC.
I know my MPC sounds rather lifeless without some corrective EQ. You not only get great sounding mic pre's, you get the line input, as well as an Instrument input for GTR's and Bass.
The overall tone of the AFC-2 is very smooth and clear. It won't mess with your tone from the synth's at all!! Unless you throw in the EQ and carve away.
check it out. Toft Audio Designs