The answer is simple. If you're plugging your preamplifier into a quality studio console like an API or Neve, you want 600 ohms. If you are plugging into a Tascam or other consumer piece of crap, you want 10,000 ohms. If it has a 600 ohm output, you are going to want to terminate that output with a 600 ohm resistor (in all actuality, 620 is more common) or into a 600 ohm input transformer. No amateur beginner crap will have that. They will all be at least 10,000 to 50,000 ohm inputs. The professional output will also be + 4 DBM. The consumer items will be somewhere around -10 DBu and really cannot handle professional studio line level stuff without overloading.

Living in the professional world
Ms. Remy Ann David

What would you consider a Lucid ad9624? That's what its running into.

Lucid indicates that your unit has a XLR analog input connector and so it accepts higher line level balanced signals. If you are using that input connector I would suggest you switch your unit into 600 ohms. Your unit is designed to accept balanced studio line level inputs.

If you are using a 1/4 inch analog input (if that unit even has one), switch your unit to 10,000 ohms. It's that simple.

Simpleton
Ms. Remy Ann David

Thanks for the info!