Hi. I just picked up an Eastern Electric Tube DAC Plus (aka Minimax DAC Plus, the no volume control version) on Audiogon and tried some 12au7 tube rolling. It came with a PSVane which was OK but I knew I could do better. Mullard NOS was disappointing, fuzzy with no low or high end extension. JAN Philips Blue NOS was very nice with solid bass and extended treble and very good tube dimensionality also. Best so far is NOS Toshiba short plate halo getter. All frequencies are there with lots of tube presence and great dimensionality.