is a 555:1 impedance ratio ok?

Yes, you need to match the preamp to the EQ box. I don't think you'll have any problem - the input impedance will likely be at least 75K, and as others have mentioned, that is high enough.

Good luck.

i'm not sure if this posted correctly before, so forgive me if this is a double.

does the output impedance of the EQ box change if i switch between two different preamps with different output impedances?

i think i need clarification on the relationships between input/output impedances when components are connected in chains.

The answer to your question is no. The output impedance of the EQ box is independent of the pre-amp feeding it. Or it should be.

Drubin is right. The active circuitry in the EQ isolates the input impedance from the output impedance.