Passive Preamp Problem

I am looking to find a passive preamp to replace my nakamichi ca-7a. But I read somewhere that you need to match your components' correctly for a passive preamp to have good results. But I don't know how to do that. My DAC is a Cal Audio Sigma with 2vrms output with 2ohm output impedance. And my amp is an Aragon 8002 with 120mB for 1watt output input sensitivity and 22k ohms input impedance. I am not sure what all these figures mean. I hope someone here can help me figure it out whether a passive will sound good with my gear. I am contemplating on getting the Creek obh-12.