Good comments by the others, with which I am in general agreement.
But fwiw I'll mention that for various reasons, on several occasions with several different pieces of equipment, I have used a preamplifier connected into a line-level input of an integrated amplifier, and I have also used two preamplifiers connected in series, ahead of a power amplifier. In no case did I have a problem with overload or excess gain.
Typically I found that setting the volume control on the integrated amplifier, or the second preamp in the chain, to around 11 or 12 o'clock would result in the volume control on the first preamp being used in a reasonable part of its range.
The specs on the CAP101
don't indicate input overload voltage, and its overall (line stage + power stage) gain of 60.5 db (at maximum volume control setting) is probably a bit higher than average, but I still think you would be ok doing that.
Also, like some of the others my experience has been that a tube power amp is the most significant factor in achieving the benefits of "tube sound," but in fairness there are a significant number of others who have expressed the opposite viewpoint in previous threads here, claiming that using a tube preamp with a solid state power amp better preserves tube-like character than the opposite combination.