The input sensitivity of the crest is listed as 1V. This means 1V input will drive the amplifiers output to max. The Tascam is capable of 2V. You are good to go.
Problems exist when the output prepro cannot deliver the rated input sensitivity of the power amplifier. Ie. 2V output when input sensitivity is 4V. This means the prepro cannot drive the amplifier to max output.
The article Socket linked gave me the quick and dirty too.
Helpful, and a good wood finisher.