I have made references in the past on this forum to the Pre-Amp suggested in a earlier post in this thread.
The basic model will cost not much more than what might be what the OP expects to spend a their minimum outlay.
The follow is a copy/paste from another thread. It will show one reason why I have made the suggestion about this model.
"One of the above KB1 owners had a Loan of a Bespoke Built KB1 at the time they were having demo's of Pre Amp's to be used with EAR Power Amp's, approx' £20000 of Pre-Amp's were home demo'd of which one was a EAR 868 and retailing at £5000. The Pre-Amp options were not limited to a Budget, the KB1 won the system owners favour, and a Bespoke Built KB1 is used in the system.
Note: The KB1 does not do full bodied/lush as a presentation."