The nice folks at Parts Express sent over an amazing-sounding little amplifier, the $129 Topping TP30. It's a tiny desktop Class T amp design, with one analog RCA stereo input and one USB connection (the TP30 has a built-in digital-to-analog converter). The amp delivers 15 watts per channel to 4 ohm-rated speakers (10 watts into 8 ohms), and has a 3.5 mm headphone jack on the front panel.
With its extruded aluminum chassis, 8mm thick, CNC-machined front panel, and solid-metal volume control knob the TP30 wouldn't look out of place in a high-end system. It even feels expensive, but I have just one nitpick: the illuminated blue LED ring surrounding the volume control knob is too bright. I wish there was a way to dim it or turn it off. The amp measures a tidy 4.13 inches by 1.77 inches by 8.07 inches.
The USB interface utilizes standard Windows audio class 1 drivers (it worked fine with my Mac mini). Internal parts quality is superb; the TP30 boasts Elna capacitors, Dale resistors, and an ALPS volume control. The Burr-Brown USB digital-to analog converter chip accepts up to 48 kHz sampling rates with 16-bit resolution.
I compared the sound of the TP30 with my Audioengine N22 amp ($199), and they're both pretty good. The N22 has a fuller, warmer tonal balance, but the TP30 has a more immediate, detailed sound with more tightly controlled bass. I used my Audioengine P4 speakers for all of my speaker-based listening tests. It's interesting, the TP30 is a digital amp and takes digital signals "straight-in" via its USB port; the N22 is analog-only and is a more traditional Class A/B amplifier design. It sounded softer, and a wee bit less defined than the TP30.… Read more