Overall, the Mini-T's performance is perfectly acceptable in light of its $69 street price, and its 10 watts were capable of more volume than I needed in my small office (although the music started to take on a harsh edge when the amp was pushed to higher volume levels). If you don't listen too loudly, the Mini-T can also perform capably in a larger room, matching or exceeding the volume level of most inexpensive smartphone speaker docks.
After swapping cables to accommodate different speaker wire and input connectors, I fired up the DTA--100a, and I found a notable increase in performance. Bass tightened up and increased in volume, treble frequencies came into focus and lost some harshness, and midrange frequencies increased in detail and texture. The music's pacing also seemed to improve, likely due to better resolution of transients. Like the Orb, the Dayton did strain at higher volumes, with the music becoming increasingly harsh, but with the DTA--100a, such volumes were excessively loud in my desktop setup.
I did encounter a couple of issues with the Dayton's volume control. At lower levels, the volume didn't change as smoothly as it did with the Orb, sometimes dropping off suddenly--achieving a quiet level of playback took some finesse. And at these low levels, the stereo balance shifted noticeably to the left side, suggesting that the right side's output level was attenuated more quickly than the left side's. I didn't notice this at higher volumes, however, and this sort of issue is common in inexpensive amplifiers. But if you have particularly efficient/sensitive speakers (in other words, speakers that can produce your desired listening levels without much power), or if you like to listen at very low volumes, it could be annoying.
Finally, I hooked up the Audioengine N22, and I heard the Pioneer speakers sound their best. Through the N22, bass was strong and tight, and high frequencies natural, without artificial harshness. When I pushed the N22 to louder volumes, it continued to perform well. In fact, when testing the N22 at loud volumes, I encountered the limitations of my listening setup--audible resonance from my desk--before I heard problems with the amplifier itself. Unless you're using substantially bigger speakers in a large room, or need extremely loud volumes, the N22 will likely provide plenty of power. One minor complaint is that the volume knob feels a little loose; it could benefit from more friction.
The three models here are similar in size and capability to several of the DAC-endowed models I previously reviewed. To put the performance of these DAC-less models into perspective, I compared the DTA--100a to the $180 Topping TP30, and the N22 to the the $229 NuForce Dia (4 of 5 rating) and its discontinued $349 sibling, the Icon--2 (3.5 of 5 rating).
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