I have the tone controls off (there's a defeat button on my amp).
Going back to the bit about using USB - is your laptop a Windows machine?
There can be readily noticeable gains to be had with Windows machines using WASAPI or ASIO drivers for the connected audio device (in your case the DAC).
It's all to do with prioritising Windows resources to audio playback.
Does Media Monkey have such drivers to plug into your existing installation?