Added the T20 to my main rig, which includes a Musician R2R DAC, Purifi-based VTV power amp, and Magneplanar 1.7i speakers. Noticed immediate improvement in instrument layering/separation, and a tad more bass extension. Was expecting to hear a slight drop in detail, but can't say for sure if that's the case. Very pleased with the impact of the T20, even with the stock tubes. It's a modest but handsome unit, with a simple and responsive remote. All I needed was an inexpensive way to add 12AX7 type tubes to the signal chain with a quality circuit design using those quiet and low-distortion Texas Instrument op amps. Will be fun to roll other tubes to see what happens.