I use the Wyred 4 Sound DAC-2 into an STI-500. Since the STI-500 has its own volume control, I run the DAC-2 in its fixed-volume mode with great results.
I can recommend the My Audio Cables (MAC) HC Soundpipes power cord. It's inexpensive and it works great for an expansive soundstage and great dynamics.
I'm also using the MAC CUQ speaker cables which seem to sound even better when using the aforementioned MAC HC power cord.
MAC also makes some great sounding interconnects, but I'm using a combination of MAC and SignalCable interconnects.
BTW, I had the EE Minimax DAC in my system and directly compared it to the DAC-2. The EE sounded dismal via the solid-state outputs but much better through the tube outputs. Even then it was not even close to the performance of the W4S DAC-2. The DAC-2 was much more coherent octave to octave, plus it is way more detailed, much less noisy, and more dynamic to boot.
The less expensive W4S DAC-1 should perform pretty close to the DAC-2... and you won't need to worry about which NOS tube sounds best.