Save your money. You have one source. By the time you have found the right cables and a preamp you will wish you never started.
Every preamp I have tried, gave with one hand and took away with the other.
If you have leading edge information and clarity to spare then maybe you will find a preamp that will work for you.
However you may be better off finding a DAC with switchable voltage on the output and volume control. There are a few out there, and I am sure over the coming months many more.