@almarg has presented some very relevant facts. The OP has aging components that should be addressed first. Plus, I doubt that his amp and preamp are revealing enough to warrant adding tweaks such as aftermarket outlets and power.
Building the foundation of the system should come first. As stated earlier, an integrated amp would be a good way to go.
Building the foundation of the system should come first. As stated earlier, an integrated amp would be a good way to go.